Conditions

Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit that produces comedones and inflammatory lesions; treatment is selected by severity, scarring and psychological impact, with strict antimicrobial stewardship and pregnancy safeguards for retinoids and tetracyclines.

Acromegaly is adult growth-hormone excess, usually from a pituitary somatotroph adenoma, producing progressive acral and facial change and important cardiovascular, metabolic, respiratory and musculoskeletal complications.

Acute bronchitis is a usually viral, self-limiting acute cough syndrome caused by temporary inflammation of the conducting airways; the high-yield task is to exclude pneumonia, serious illness and an exacerbation of underlying airways disease before avoiding unnecessary antibiotics.

Acute coronary syndrome (ACS) is acute myocardial ischaemia, usually from thrombosis on a disrupted coronary plaque, triaged by the first ECG into a reperfusion pathway or a troponin pathway.

Acute kidney injury is a measurable fall in kidney filtration or urine output caused by reduced perfusion, intrinsic renal disease or obstruction; identify the cause early, protect the kidneys, monitor complications and escalate for refractory life-threatening physiology.

Massive hepatocyte necrosis in a liver with no pre-existing disease strips out clotting-factor synthesis and ammonia clearance, so coagulopathy and encephalopathy appear together within days to weeks.

A maturation arrest in the lymphoid lineage lets lymphoblasts proliferate and fill the marrow, causing rapid marrow failure plus a distinctive tendency to infiltrate the central nervous system and testes; it is the commonest childhood cancer.

A maturation arrest in the myeloid lineage lets myeloblasts proliferate and fill the marrow, so normal blood production collapses over days to weeks into the anaemia, infection and bleeding of marrow failure, most often in an older adult.

Acute pancreatitis is pancreatic inflammation with local and systemic inflammatory consequences; diagnose it clinically and biochemically, treat early with monitored supportive care and enteral nutrition, and prevent recurrence by addressing the cause.

Acute pericarditis is inflammation of the pericardium causing sharp pleuritic and positional chest pain, with or without an effusion; diagnose it while excluding acute coronary and other life-threatening chest-pain causes, then risk-stratify for secondary disease, tamponade and myopericarditis.

Acute pyelonephritis is an upper urinary tract infection involving the renal pelvis and parenchyma; fever, loin pain and systemic upset are the key clues, while sepsis or an obstructed infected system makes it an emergency.

ARDS is acute diffuse inflammatory injury of the alveolar-capillary barrier causing bilateral pulmonary opacities and severe hypoxaemic respiratory failure not fully explained by cardiac failure or fluid overload; treat the trigger while delivering lung-protective critical care and escalating early when oxygenation remains refractory.

Primary adrenal insufficiency: the cortex fails, so cortisol and usually aldosterone are lost together, and any physiological stress can tip a stable patient into adrenal crisis.

Alcohol-related liver disease ranges from reversible steatosis through alcohol-related hepatitis to cirrhosis; assess both the liver stage and alcohol-use disorder because abstinence, nutrition and specialist care change prognosis at every stage.

A rapidly developing systemic hypersensitivity reaction in which mast-cell mediator release obstructs the airway, closes the small airways and empties the circulation, reversed by intramuscular adrenaline given within minutes.

Radiographic axial spondyloarthritis causing inflammatory back pain, sacroiliitis and progressive structural new bone formation in susceptible people.

Anogenital warts are usually benign HPV-related epithelial lesions, most often associated with low-risk types 6 and 11; diagnose them clinically, biopsy atypical or treatment-resistant lesions, and choose observation, topical treatment or ablation by site, morphology, pregnancy status and patient preference.

Choose anticoagulation by indication, thrombotic risk, bleeding risk, renal function and patient preference; warfarin and direct oral anticoagulants have different monitoring, interactions and reversal pathways.

A tear in the aortic intima drives blood into the media, splitting it into a true and a false lumen that can rupture or occlude branch arteries.

Aortic regurgitation allows blood to leak back into the LV during diastole, causing volume overload and progressive ventricular dilatation.

Progressive narrowing of the aortic valve creates left-ventricular pressure overload; symptomatic severe disease needs specialist valve-team assessment for intervention.

Chronic airway inflammation leaves bronchial smooth muscle hyper-responsive, so airway calibre and expiratory airflow vary over time, with triggers, and with treatment.

Atopic eczema is a chronic, relapsing, intensely itchy inflammatory skin disorder in which epidermal barrier dysfunction and immune dysregulation reinforce each other; management combines daily skin care, prompt anti-inflammatory treatment, infection recognition and escalation according to severity and life impact.

Disorganised atrial electrical activity abolishes coordinated atrial contraction, so the atrioventricular node is bombarded irregularly and blood stagnates in the left atrial appendage.

Atrial flutter is a single organised re-entry circuit, usually running around the tricuspid valve, and the ventricular rate is whatever fraction of it the atrioventricular node lets through.

B12 or folate deficiency impairs DNA synthesis and can cause megaloblastic cytopenias; B12 deficiency additionally threatens the nervous system, so it must be recognised and replaced promptly, especially before or alongside folic acid.

Bell's palsy is an acute idiopathic unilateral peripheral facial-nerve palsy; forehead involvement and isolated lower-motor-neurone weakness support the diagnosis, but eye protection and exclusion of stroke, Ramsay Hunt syndrome and other causes are essential.

Benign prostatic enlargement can narrow the bladder outlet and produce mixed lower urinary tract symptoms, but symptom severity, bladder function and complications—not prostate size alone—determine management.

Benign skin lesions are common non-malignant growths such as seborrhoeic keratoses, epidermoid cysts, dermatofibromas, skin tags, lipomas and naevi; the high-yield skill is recognising reassuring patterns while identifying the changing, symptomatic or atypical lesion that needs specialist assessment or biopsy.

Bladder cancer most often presents with painless haematuria; cystoscopy and TURBT establish the diagnosis and depth of invasion, separating non-muscle-invasive disease from muscle-invasive disease that needs specialist radical-treatment planning.

Bone tumours include benign lesions, rare primary bone sarcomas, myeloma and secondary deposits; the high-yield task is to recognise persistent or unexplained bone pain, swelling, a pathological fracture or an aggressive radiograph, investigate promptly and ensure that suspected primary bone tumour is referred before biopsy to an expert sarcoma centre.

Disease of the conducting tissue delays or blocks atrial impulses reaching the ventricles, leaving a slow escape rhythm whose site of origin decides how dangerous the block is.

A brain abscess is a focal intracranial collection of infected material that combines a deep infection with an expanding mass, requiring urgent neurosurgical, infectious-disease and source-control management.

Brain tumours are primary or metastatic intracranial neoplasms that can present through seizures, progressive focal dysfunction or raised intracranial pressure; diagnosis and treatment depend on imaging, tissue, molecular profile, site and performance status.

Bronchiectasis is permanent bronchial dilatation with impaired mucus clearance, recurrent infection and inflammation; high-quality care combines CT confirmation, aetiology work-up, physiotherapist-led airway clearance, culture-directed antibiotics and specialist prevention of exacerbations.

Bursitis is inflammation or infection of a fluid-filled bursa, usually causing a localised swelling over a pressure point; the safety-critical task is to distinguish non-septic bursitis from septic bursitis, septic arthritis, crystal disease and a mass.

Candidiasis is infection by Candida yeasts, usually a superficial mucocutaneous infection but occasionally invasive candidaemia; the key clinical task is to distinguish symptomatic disease from colonisation and match treatment to site, host, species, susceptibility and pregnancy status.

Carbon monoxide binds haemoglobin far more avidly than oxygen, so oxygen carriage collapses while the arterial oxygen tension and the pulse oximeter both stay deceptively normal.

Fluid, blood, pus or gas in the pericardial sac raises the pressure around the heart until the ventricles cannot fill, so cardiac output falls despite normal contractility.

Cardiomyopathy is a primary myocardial disorder classified by its structural and functional phenotype; it may present with heart failure, arrhythmia, syncope or a family history and requires specialist phenotyping, aetiological assessment, sudden-death risk review and family screening.

Blood enters the wall of a cervical carotid artery and forms an intramural haematoma whose raw surface embolises to the retina or brain, hours to days after the pain starts.

An acute bacterial infection of the dermis and subcutaneous tissue causing spreading inflammation; the essential clinical task is to distinguish uncomplicated cellulitis from sepsis, orbital disease, abscess and necrotising fasciitis.

Cerebral venous sinus thrombosis is thrombosis of a dural venous sinus or cerebral vein that obstructs venous drainage, causing raised intracranial pressure, venous infarction, haemorrhage, seizures and focal or diffuse neurological dysfunction.

Chlamydia trachomatis is an often-silent sexually transmitted infection of columnar epithelium. The high-yield priorities are site-appropriate NAAT, prompt treatment, partner notification, pregnancy-aware prescribing and recognition of ascending or extragenital complications.

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a disabling long-term illness diagnosed from a characteristic symptom pattern, especially post-exertional malaise, after assessment for alternative and coexisting conditions; management is person-led energy management and symptom support, not fixed graded exercise.

Heart failure is a clinical syndrome in which a structural or functional cardiac abnormality raises filling pressures, lowers cardiac output, or both. Ejection fraction then chooses the treatment; it does not make the diagnosis.

Diagnose CKD by persistent reduced GFR or a marker of kidney damage, stage it with eGFR and ACR, then reduce cardiovascular and kidney-failure risk through blood-pressure control, renoprotective treatment, monitoring and timely renal referral.

A clonal accumulation of mature but functionally incompetent B lymphocytes that pile up slowly in blood, marrow and nodes rather than dividing rapidly, so most patients are asymptomatic for years and the disease is found incidentally on a routine blood count.

A single acquired fusion gene, BCR-ABL1 from the Philadelphia chromosome, creates a constitutively active tyrosine kinase that drives myeloid overproduction with preserved maturation, so the blood fills with maturing granulocytes and the spleen enlarges, usually indolently until it is controlled by a targeted inhibitor.

Persistent airflow obstruction caused by small-airway inflammation and emphysematous loss of elastic recoil, so the lungs cannot empty fully and gas is trapped with every breath.

Antibiotic-associated, toxin-mediated colitis in which loss of gut colonisation resistance permits C. difficile to proliferate, causing diarrhoea that may progress to ileus, toxic megacolon and perforation.

A trigeminal autonomic cephalalgia causing recurrent, very severe strictly unilateral orbital or temporal attacks with ipsilateral cranial autonomic features, restlessness and a cluster pattern.

An immune-mediated response to dietary gluten that injures the small-bowel mucosa and causes gastrointestinal or extraintestinal disease; confirm it while gluten is being eaten before starting a lifelong gluten-free diet.

An acute infection of the lung parenchyma acquired outside hospital that fills alveoli with inflammatory exudate and impairs gas exchange. Confirm the syndrome, assess severity and sepsis risk, and start appropriate antibiotics promptly.

Congenital heart disease comprises structural heart or great-vessel abnormalities present from birth; classify the physiology as shunt, obstruction, abnormal mixing or single-ventricle circulation, then recognise duct-dependent neonatal collapse, cyanotic spells, heart failure and the need for lifelong specialist follow-up.

Constipation is unsatisfactory defaecation because stools are infrequent, hard, difficult or incomplete; most is functional or medication-related and responds to a stepwise laxative plan, but obstruction, impaction and colorectal-cancer symptoms must be recognised before routine treatment.

Contact dermatitis is eczema caused by an external contactant: irritant disease is dose-dependent barrier injury, whereas allergic disease is a delayed T-cell-mediated reaction in a sensitised person.

Contraceptive care is a person-centred process of assessing pregnancy risk, medical eligibility, interactions and preferences, then providing the acceptable method that best meets the person's priorities.

COVID-19 is illness caused by SARS-CoV-2, ranging from a self-limiting respiratory infection to hypoxic pneumonia and multi-organ complications; management depends on severity, oxygen requirement, risk of progression, timing, comorbidity and current UK treatment pathways.

Patchy inflammation of any part of the gut from mouth to anus that extends through the full thickness of the bowel wall, producing strictures, fistulae and abscesses.

An acute hot-joint syndrome caused by crystal-triggered inflammation; aspirate when uncertain to distinguish monosodium urate, calcium pyrophosphate and septic arthritis, then tailor acute and long-term care to the result.

Chronic glucocorticoid excess, usually caused by prescribed steroids, produces a recognisable catabolic and metabolic phenotype; endogenous disease needs specialist biochemical confirmation and source localisation.

Cystic fibrosis is an autosomal-recessive CFTR disorder in which abnormal epithelial salt and water transport produces dehydrated secretions, chronic suppurative lung disease, pancreatic insufficiency and multisystem complications; modern UK care combines specialist prevention, infection control, nutrition and genotype-directed CFTR modulation.

A DVT is a venous clot, usually in a leg vein, that can extend or embolise to cause PE; diagnose it with a validated pathway and treat confirmed proximal disease with anticoagulation.

A syndrome of acquired cognitive and functional decline whose cause must be established through longitudinal history, collateral information, examination and targeted investigation, with delirium and treatable contributors addressed first.

Diabetes insipidus is the passage of excessive dilute urine because arginine vasopressin is deficient (AVP-D, formerly cranial DI) or the kidney is resistant to it (AVP-R, formerly nephrogenic DI); the immediate danger is hypernatraemic dehydration when thirst, water access or desmopressin fails.

Insulin deficiency lets the liver overproduce glucose and acidic ketone bodies at once, giving hyperglycaemia, ketonaemia and a high-anion-gap metabolic acidosis on top of profound osmotic dehydration.

Digoxin inhibits the myocardial sodium-potassium pump, so in excess it both blocks conduction and provokes ectopic firing, giving bradycardia, heart block and ventricular arrhythmia.

Disseminated intravascular coagulation is a dynamic, acquired syndrome of systemic coagulation activation driven by another serious illness, causing microvascular thrombosis while consuming platelets and clotting factors; treat the trigger first and support bleeding selectively.

Down syndrome is a chromosomal condition caused by an extra copy of chromosome 21, with variable learning disability, hypotonia and characteristic features plus a higher chance of treatable cardiac, gastrointestinal, endocrine, hearing, visual, sleep, haematological and neurological problems.

A group of heritable connective-tissue disorders with variable joint, skin and tissue fragility; hypermobile EDS and hypermobility spectrum disorder are usually clinical diagnoses, while vascular EDS is rare and can cause arterial, bowel or uterine rupture.

Empyema is infected pleural fluid, usually arising from pneumonia and progressing from a simple parapneumonic effusion to loculated pus; antibiotics are essential but source control requires image-guided drainage, with intrapleural therapy or surgery when drainage is incomplete.

Encephalitis is inflammation of the brain parenchyma causing altered mental state, seizures or focal neurological dysfunction, usually from infection or autoimmunity; suspected herpes-simplex encephalitis needs immediate empirical intravenous aciclovir while investigations are arranged.

Kidney failure is stage 5 chronic kidney disease with insufficient renal function to maintain homeostasis; care is planned around symptoms, biochemical complications, patient goals and the choice between dialysis, transplantation and supported conservative management.

Axial or peripheral spondyloarthritis associated with Crohn’s disease or ulcerative colitis, requiring coordinated gastroenterology and rheumatology care.

An epididymal cyst is a benign, usually painless extratesticular cyst; the key task is to confirm that the testis itself is normal and to escalate any uncertain or intratesticular mass.

Epididymo-orchitis is acute inflammation of the epididymis with or without testicular involvement, usually from ascending sexually transmitted or urinary pathogens; the first decision is whether the acute scrotum could be testicular torsion, because imaging and antibiotics must never delay urgent exploration.

A disorder of enduring susceptibility to recurrent seizures caused by abnormal, hypersynchronous electrical activity in brain networks; diagnosis is clinical, seizure type determines treatment, and prolonged or repeated seizures are emergencies.

Erythema nodosum is a tender septal panniculitis and reaction pattern, usually presenting with bilateral shin nodules that fade like bruises; the key task is identifying an infectious, inflammatory, drug-related, pregnancy-related or other trigger.

A myeloproliferative neoplasm in which clonal megakaryocyte proliferation, usually driven by JAK2, CALR or MPL, sustains a high platelet count; the raised, functionally abnormal platelets cause both thrombosis and, paradoxically at very high counts, bleeding, so it is a diagnosis of exclusion once reactive thrombocytosis is ruled out.

Essential tremor is an isolated, usually bilateral upper-limb action tremor lasting at least 3 years, diagnosed clinically after characterising the tremor and excluding parkinsonism, dystonia, ataxia, drugs and systemic causes.

Trauma tears the middle meningeal artery against the thin temporal bone, and arterial pressure strips the dura off the skull, so the collection grows in hours rather than days.

Fibromyalgia is a chronic primary pain condition characterised by widespread pain with fatigue, unrefreshing sleep and cognitive difficulty; it is diagnosed clinically while assessing mimics and coexisting disease, and managed with person-centred exercise, psychological approaches, symptom care and selective medicine review rather than routine analgesics.

A reproducible immune-mediated reaction to a specific food, ranging from immediate IgE-mediated urticaria or anaphylaxis to delayed non-IgE-mediated skin and gastrointestinal disease; it is distinct from non-immune food intolerance.

Dermatophyte fungi digest keratin in the stratum corneum and spread outward as they consume it, producing a scaly lesion with an actively advancing, inflamed edge and a clearing centre, the ring that gives ringworm its name.

Reflux of gastric contents across an ineffective gastro-oesophageal barrier causes troublesome symptoms or mucosal injury; the clinical priority is to recognise alarm features, treat typical disease safely, and investigate persistent or unexplained symptoms objectively.

Genital herpes is a lifelong HSV infection with latent virus in sensory ganglia, causing painful first episodes and usually milder recurrences; diagnosis, partner counselling, antiviral treatment and pregnancy planning are the core UK pathway.

A large- and medium-vessel vasculitis in people over 50 that can cause irreversible visual loss, requiring immediate glucocorticoid treatment when strongly suspected and urgent specialist confirmation.

Glomerulonephritis is a pattern of glomerular injury that may present with haematuria, proteinuria, oedema, hypertension or acute kidney injury; active urine sediment with rapidly worsening renal function needs urgent nephrology assessment.

Neisseria gonorrhoeae is a sexually transmitted infection whose treatment is governed by antimicrobial resistance. The safe pathway is site-complete NAAT plus culture and susceptibility testing, ceftriaxone-led treatment, resistance-aware test of cure and urgent escalation for disseminated or ocular disease.

An inflammatory arthritis caused by monosodium urate crystals; treat the flare promptly, exclude septic arthritis when the diagnosis is uncertain, and prevent recurrence with treat-to-target urate-lowering therapy.

An acute immune-mediated polyradiculoneuropathy causing progressive symmetrical weakness, areflexia and potentially rapid respiratory or autonomic failure.

Haemophilia is an inherited deficiency of factor VIII (haemophilia A) or factor IX (haemophilia B), causing impaired fibrin formation and a characteristic tendency to bleed into joints, muscles and deep tissues; urgent specialist treatment is needed for significant bleeding or procedures.

Hepatocellular carcinoma (HCC) is a primary hepatocyte cancer usually arising in cirrhosis or chronic hepatitis B; early detection and treatment must account for both tumour burden and the reserve of the underlying liver.

Hereditary haemochromatosis is inherited dysregulation of iron absorption, usually from HFE C282Y homozygosity, causing progressive parenchymal iron overload; early recognition and specialist venesection can prevent irreversible liver, endocrine, cardiac and joint damage.

Herpes simplex virus causes recurrent painful mucocutaneous lesions and can also cause sight-threatening keratitis, encephalitis, eczema herpeticum, neonatal disease and disseminated infection; management depends on site, severity, host, pregnancy and timing.

A chronic retroviral infection that progressively impairs CD4-mediated immunity, but is now usually controllable with antiretroviral therapy that protects health and prevents sexual transmission when viral suppression is sustained.

An autosomal-dominant neurodegenerative disorder caused by a CAG-repeat expansion in HTT, producing progressive motor, cognitive and psychiatric change; diagnosis and predictive testing require specialist genetics support and treatment is symptomatic and multidisciplinary.

A hydrocoele is a fluid collection around the testis; uncomplicated infantile hydrocoeles often resolve, while new, atypical or adult swellings require confident testicular assessment and surgery only when symptoms or cause justify it.

Hydronephrosis is dilatation of the renal collecting system, usually caused by impaired urine drainage; localise the cause, protect renal function, and treat an infected obstructed kidney as a urological emergency.

Hypercalcaemia is a raised albumin-adjusted serum calcium, most often caused by primary hyperparathyroidism or malignancy; PTH is the pivotal fork, while severe or rapidly symptomatic hypercalcaemia is an emergency requiring careful rehydration and specialist treatment.

Raised extracellular potassium partially depolarises cardiac myocytes and slows conduction, so the lethal risk is arrhythmia and cardiac arrest rather than the number on the result.

Hyperlipidaemia is raised atherogenic lipoprotein cholesterol or triglycerides; it is usually silent, so treatment is based on overall cardiovascular risk, established disease, familial lipid disorders and pancreatitis risk rather than on a cholesterol number in isolation.

Hypernatraemia is usually a deficit of water relative to sodium; assess volume status and urine concentration, restore circulation first if shocked, then replace water in a controlled specialist-led plan.

In hyperosmolar hyperglycaemic state (HHS), residual insulin suppresses ketone production but not hyperglycaemia, so days of osmotic diuresis produce extreme dehydration and hyperosmolality rather than acidosis.

Hyperparathyroidism is excessive parathyroid hormone secretion: primary disease causes hypercalcaemia through autonomous gland activity, while secondary disease is an appropriate response to chronic kidney disease or vitamin-D deficiency and tertiary disease becomes autonomous after prolonged stimulation.

Hyperprolactinaemia is a raised prolactin concentration caused by physiology, medicines, systemic disease, stalk interruption or a prolactinoma; confirm the result and find the cause before treating the number.

Hypertension is persistently raised arterial blood pressure, usually without symptoms, diagnosed by correctly measured clinic pressure plus ambulatory or home confirmation unless severe pressure and acute target-organ injury require immediate specialist assessment.

In hyperthermia the hypothalamic set-point is normal and heat load simply outstrips heat loss, so antipyretics have nothing to act on and physical cooling is the only disease-modifying treatment.

A state of thyroid hormone excess that accelerates metabolic rate across almost every tissue, so the clinical picture (weight loss despite hunger, heat intolerance, tachycardia and tremor) can be derived directly from asking what a sped-up metabolism looks like.

Hypocalcaemia is low biologically available serum calcium, usually from hypoparathyroidism, vitamin-D deficiency, chronic kidney disease or hypomagnesaemia; rapid or symptomatic hypocalcaemia causes tetany, seizures, laryngospasm and QT prolongation and requires urgent treatment.

The brain can neither make nor store glucose, so when circulating insulin outlasts the available carbohydrate the counter-regulatory response cannot keep up and neuroglycopenia follows within minutes.

Hypokalaemia is a serum potassium below 3.5 mmol/L, usually from gastrointestinal or renal loss or a transcellular shift; assess the ECG and symptoms urgently, replace potassium safely, correct magnesium and treat the cause.

Hyponatraemia is a low serum sodium, usually reflecting excess water relative to sodium; assess symptoms and osmolality urgently, treat severe neurological symptoms immediately, then classify the cause and control the rate of correction.

Hypoparathyroidism is deficient parathyroid hormone secretion or action, most often after neck surgery, causing hypocalcaemia with hyperphosphataemia; acute symptoms need emergency calcium treatment, while chronic care balances active vitamin D and calcium against hypercalciuria and renal injury.

Hypopituitarism is deficiency of one or more pituitary hormones, producing secondary adrenal, thyroid, gonadal or growth-hormone failure; glucocorticoid deficiency is the immediate life threat, so cortisol replacement and stress cover come before thyroid replacement.

Hyposplenism is reduced splenic function and asplenia is absent splenic function; both impair clearance of blood-borne organisms and make rapidly progressive infection, particularly with encapsulated bacteria, a lifelong emergency risk.

Accidental hypothermia is a core temperature below 35°C: cooling leaves an irritable myocardium that handling alone can tip into arrest, while protecting the brain enough that prolonged resuscitation still works.

A state of thyroid hormone deficiency that slows metabolic rate in virtually every tissue, so the whole clinical picture (from bradycardia to cold intolerance to slowed cognition) can be predicted simply by asking what happens when metabolism runs too slowly.

Immune thrombocytopenia is an acquired immune-mediated platelet disorder causing isolated thrombocytopenia and a mucocutaneous bleeding phenotype; diagnosis is one of exclusion, and treatment is guided by bleeding risk, platelet count, comorbidity and treatment burden rather than the count alone.

Impetigo is a contagious superficial bacterial skin infection, usually caused by Staphylococcus aureus or Streptococcus pyogenes, presenting as non-bullous crusted erosions or bullous flaccid blisters.

Acute infectious diarrhoea with or without vomiting, managed by prioritising hydration and sepsis assessment, testing selectively, avoiding harmful antibiotics in STEC, and controlling transmission and public-health risk.

Infectious mononucleosis is usually primary Epstein–Barr virus infection causing fever, exudative pharyngitis, lymphadenopathy and marked fatigue; the high-yield safety issues are avoiding unnecessary aminopenicillins, protecting an enlarged spleen and recognising airway, abdominal, hepatic, neurological and haematological complications.

Infective endocarditis is infection of the endocardium, usually a valve or intracardiac device; obtain adequate blood cultures, image early and involve the endocarditis team urgently.

An acute respiratory viral infection whose rapid antigenic change allows it to repeatedly evade population immunity, producing seasonal epidemics and occasional pandemics.

Interstitial lung disease (ILD) is a heterogeneous group of disorders causing inflammation and/or fibrosis of the lung parenchyma; diagnosis depends on exposure and connective-tissue assessment, HRCT, physiology and specialist multidisciplinary review, while treatment is cause-specific and progression-focused.

Bleeding within the fixed skull can rapidly raise intracranial pressure, reduce cerebral perfusion and cause herniation; the location and mechanism classify extradural, subdural, subarachnoid or intracerebral haemorrhage, but every type needs urgent CT, physiological stabilisation and specialist escalation.

Iron-deficiency anaemia reflects depleted iron available for haemoglobin production; replace the iron, but always investigate the pattern of loss, demand or malabsorption that caused it.

A chronic disorder of gut-brain interaction diagnosed positively from abdominal pain related to defaecation or altered stool pattern, once relevant red flags and targeted tests have been addressed.

Juvenile idiopathic arthritis (JIA) is persistent inflammatory arthritis beginning before the 16th birthday and lasting at least 6 weeks after other causes have been considered. It is a group of diseases in which silent anterior uveitis, joint damage, growth disturbance and systemic inflammation make early specialist assessment essential.

A sex-chromosome condition, usually 47,XXY, causing variable testicular dysfunction and androgen deficiency; it may present with small firm testes, tall stature, gynaecomastia, learning or psychosocial needs, delayed puberty or infertility and is often diagnosed late.

A leg ulcer is a wound below the knee that fails to heal, and its cause must be established before treatment: venous, arterial, diabetic/neuropathic, pressure, inflammatory, traumatic and malignant ulcers need different pathways.

A group of malignant clonal disorders of blood-forming cells, classified along two axes that decide everything else: cell lineage (myeloid or lymphoid) and tempo (acute, a maturation arrest that fills the marrow with blasts over weeks, or chronic, a slow expansion of maturing cells over years).

Lichen planus is an inflammatory interface dermatosis causing pruritic violaceous papules with Wickham striae and potentially persistent disease of the mouth, genitals, scalp or nails.

Lithium is cleared by the kidney alongside sodium, so volume depletion, renal impairment or a drug that blocks its elimination turns an unchanged dose into rising concentrations and neurotoxicity.

Irreversible replacement of normal liver architecture by fibrous septa and regenerative nodules causes both failing synthetic function and obstructed blood flow, so every complication is one of these two mechanisms playing out.

Most low back pain is non-specific and improves with activity and self-management, but every assessment must identify cauda equina syndrome, fracture, infection, malignancy and inflammatory disease that require a different pathway.

A lung abscess is a localised collection of pus within necrotic lung parenchyma, commonly following aspiration of oral flora; it presents subacutely with fever and purulent or foul sputum, and requires prolonged specialist antimicrobial treatment while excluding empyema, obstruction, malignancy, tuberculosis and septic emboli.

A malignant lung tumour can obstruct airways, invade local structures or spread distantly; the high-yield pathway is rapid recognition, tissue and molecular diagnosis, stage and fitness assessment, multidisciplinary treatment and early supportive care.

Lyme disease is a multisystem infection caused by Borrelia species and transmitted by Ixodes ticks; diagnose erythema migrans clinically, use accredited serology for presentations without the rash, and escalate focal neurological, cardiac, ocular, joint, pregnancy and paediatric disease through the current NICE pathway.

A heterogeneous group of clonal lymphoid malignancies that may present with persistent lymphadenopathy, splenomegaly, extranodal disease or systemic symptoms; tissue classification and subtype-specific staging determine urgency and treatment.

A mosquito-borne Plasmodium infection in which travel history, species and severity determine how quickly treatment must begin.

Mallory-Weiss syndrome is an upper-GI bleed from a longitudinal mucosal tear at the gastro-oesophageal junction, classically causing haematemesis after forceful vomiting or retching; most tears stop spontaneously, but the patient still needs acute upper-GI-bleed risk assessment.

Malnutrition (undernutrition) is inadequate intake, absorption or use of energy, protein or micronutrients that impairs function and clinical outcomes; identify it with validated screening, find the cause and provide safe, individualised nutrition support.

An autosomal-dominant FBN1-related connective-tissue disorder affecting the aorta, eyes and skeleton; tall stature and ectopia lentis are recognisable clues, but progressive aortic-root disease and dissection are the life-threatening priorities.

Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD) is hepatic steatosis with cardiometabolic risk; most people are asymptomatic, so the clinical priority is identifying advanced fibrosis and reducing liver and cardiovascular risk.

Melanoma is malignant melanocytic disease requiring rapid specialist assessment, histological staging and stage-directed treatment; a changing pigmented lesion should not be reassured by a single visual rule.

Bacteria reaching the subarachnoid space provoke an inflammatory response that raises intracranial pressure and injures cranial nerves, while meningococcal bloodstream invasion adds purpura, coagulopathy and shock.

Metabolic syndrome is a high-risk clustering of central adiposity, dysglycaemia, raised blood pressure and atherogenic lipids; it is a risk marker rather than a separate disease, so management is formal cardiovascular-risk assessment plus targeted treatment of weight, glucose, lipids and blood pressure.

Metastatic spinal cord compression is compression of the spinal cord or cauda equina by malignant disease and an oncological emergency; progressive spinal pain, gait change, weakness, sensory loss or bladder/bowel symptoms in someone with current or previous cancer need immediate MSCC-pathway escalation.

A recurrent primary headache disorder causing stereotyped moderate-to-severe attacks, often with nausea and light or sound sensitivity, sometimes preceded by a gradually evolving reversible aura.

Mitral regurgitation is systolic leakage from the LV into the LA; chronic disease causes volume overload, while acute severe disease can cause pulmonary oedema.

Mitral stenosis obstructs LA emptying, causing raised LA pressure, pulmonary hypertension and AF; rheumatic disease remains the classic cause.

Motor neurone disease (MND) is a progressive neurodegenerative syndrome affecting upper and lower motor neurones, usually with preserved sensation and eye movements but possible cognitive, behavioural, bulbar and respiratory involvement; suspected MND needs prompt specialist assessment and coordinated multidisciplinary care.

A chronic immune-mediated disease of the central nervous system causing neurological lesions and symptoms that are disseminated in space and time; diagnosis is specialist-led, relapses and progression must be distinguished, and disease-modifying therapy is selected according to disease activity.

An autoimmune neuromuscular-junction disorder causing fluctuating, fatigable weakness with particular risk to ocular, bulbar and respiratory muscles.

A myeloproliferative neoplasm in which a clonal marrow drives fibroblasts to lay down reticulin and collagen, so the marrow is progressively replaced by fibrosis; blood production shifts to the spleen and liver (extramedullary haematopoiesis), producing massive splenomegaly, a leukoerythroblastic film with tear-drop red cells, and constitutional symptoms.

A clonal plasma-cell malignancy produces monoclonal immunoglobulin or light chains and damages bone, kidneys, marrow and immunity; diagnosis and treatment depend on a myeloma-defining event, disease biology, fitness and patient priorities.

A family of clonal stem-cell disorders in which a driver mutation (most often JAK2 V617F) constitutively activates JAK-STAT signalling, so one or more mature myeloid lineages are overproduced; the classic Philadelphia-negative trio is polycythaemia vera, essential thrombocythaemia and myelofibrosis, which share a mechanism but differ in which cell line dominates.

Myocarditis is inflammation of the heart muscle that can present as an acute coronary syndrome mimic, new heart failure, ventricular arrhythmia or conduction disease; the immediate priorities are to assess instability, exclude time-critical alternatives, confirm myocardial inflammation and arrange cardiology follow-up.

Bacteria spreading along fascial planes thrombose the vessels supplying the overlying tissue, so fat and fascia die while the skin above can still look nearly normal.

Nephrotic syndrome is a glomerular protein-leak state causing heavy proteinuria, hypoalbuminaemia and oedema, with important risks of thrombosis, infection, acute kidney injury and progressive kidney disease.

Central dopamine blockade, or abrupt loss of dopaminergic therapy, disables thermoregulation and motor control together, so rigid muscle generates heat faster than the body can shed it.

Anticancer treatment removes the neutrophils that both contain infection and generate its localising signs, so bacteraemia can progress to shock in a patient who still looks well.

Non-melanoma skin cancer mainly comprises basal cell carcinoma and cutaneous squamous cell carcinoma; distinguish their behaviour, refer appropriately and treat histologically confirmed disease according to site and risk.

Plaque rupture or erosion infarcts myocardium without producing persistent ST elevation, so the ECG cannot time treatment and a mortality risk score does it instead.

Obesity is chronic excess adiposity that impairs health, shaped by biological, environmental, social and genetic factors; assess risk beyond BMI, treat complications and offer sustained behavioural support, escalating to NICE-approved medicines or bariatric services when eligible.

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is recurrent upper-airway narrowing or closure during sleep, causing sleep fragmentation and intermittent hypoxaemia; diagnosis uses sleep history and objective sleep testing, while treatment is tailored to symptoms, severity, comorbidity, safety risk and treatment adherence.

Occupational lung disease is respiratory disease caused or worsened by workplace exposure, spanning occupational asthma, hypersensitivity pneumonitis, pneumoconioses and asbestos-related pleural or malignant disease; the diagnosis changes care because exposure control, specialist referral, workplace protection and compensation pathways become part of treatment.

Oesophageal varices are portosystemic collaterals, usually caused by cirrhosis, that can rupture and cause life-threatening upper gastrointestinal haemorrhage; suspected variceal bleeding needs simultaneous resuscitation, vasoactive treatment, antibiotics and urgent endoscopic control.

Excess mu-opioid activation blunts the brainstem response to carbon dioxide, so ventilation fails first; naloxone displaces the opioid, but for less time than the opioid lasts.

A clinical syndrome of joint pain, stiffness and functional limitation in which tissue remodelling, load, prior injury and low-grade inflammation interact; treatment is guided by symptoms and function, with exercise and weight management as the core interventions.

Osteomalacia is defective mineralisation of newly formed adult bone, most often from vitamin D deficiency or phosphate depletion. It causes diffuse bone pain, proximal weakness and fragility or pseudofractures, with a pattern of abnormal mineral metabolism rather than the normal biochemistry of osteoporosis.

Osteomyelitis is infection of bone acquired through the bloodstream, from adjacent tissue or by direct inoculation. It can progress to abscess, dead bone, sinus formation, vertebral neurological compromise or limb-threatening diabetic foot disease, so early cultures, imaging, specialist antibiotics and source control are central.

A systemic loss of bone strength that is usually silent until a fragility fracture, assessed with clinical fracture risk and bone density and managed with falls prevention, risk-appropriate bone protection and planned treatment follow-up.

Pancreatic cancer is most often an exocrine ductal adenocarcinoma; it may present with obstructive jaundice, weight loss, upper-abdominal or back pain, new diabetes or malabsorption, and treatment depends on specialist staging and whether the tumour is resectable.

Paracetamol overdose saturates conjugation and depletes hepatic glutathione, letting the reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI) kill hepatocytes over 24 to 72 hours while the patient still feels well.

A progressive neurodegenerative disorder causing bradykinesia with rigidity or tremor, usually asymmetrically at onset, with treatment focused on individualised motor control, non-motor symptoms, rehabilitation, safe medicines and future planning.

Pelvic inflammatory disease is an ascending upper-genital-tract syndrome, often polymicrobial; early empirical treatment limits tubal inflammation and the later risks of chronic pelvic pain, infertility, ectopic pregnancy and tubo-ovarian abscess.

Penile cancer is a rare malignancy, usually squamous cell carcinoma, presenting as a persistent penile lesion or unexplained foreskin or glans symptoms; suspected cases need prompt cancer-pathway referral and confirmed disease is managed through a specialist supra-urology MDT.

A gastric or duodenal mucosal breach occurs when H. pylori, NSAIDs or another insult overwhelms mucosal defence; the high-yield priorities are cause-directed treatment and early recognition of bleeding, perforation, obstruction and gastric malignancy.

Pericardial disease ranges from inflammation and effusion to tamponade and chronic constriction; the clinical priority is to identify the dominant syndrome, assess haemodynamic danger and cause, and match anti-inflammatory, drainage or surgical treatment to that syndrome.

Peripheral neuropathy is dysfunction of one or more peripheral nerves; the common chronic form is a length-dependent distal polyneuropathy, but focal, multifocal, autonomic, demyelinating and acute patterns require different investigation and urgency.

A catecholamine-secreting tumour of adrenal chromaffin tissue causing episodic or sustained catecholamine excess, with headache, palpitations, sweating and potentially life-threatening cardiovascular instability.

Phimosis is a foreskin that cannot be retracted over the glans; paraphimosis is a retracted foreskin trapped behind the glans and is a urological emergency because its constricting ring can cause progressive oedema and ischaemia.

A pituitary adenoma causes illness through hormone excess, local mass effect, or loss of normal pituitary function; urgent recognition of visual compromise, adrenal insufficiency and pituitary apoplexy matters more than the scan label alone.

Fluid in the pleural space can reflect systemic pressure changes, infection, malignancy, pulmonary embolism or other disease; the safe pathway is clinical assessment, ultrasound-guided classification and cause-directed treatment with urgent drainage when pleural infection is high risk.

Air in the pleural space abolishes the negative pressure holding the lung expanded, so the lung recoils inwards, and a one-way leak raises that pressure until venous return fails.

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited cystic kidney disorder causing enlarged kidneys, hypertension and progressive CKD, with important renal, hepatic, vascular, reproductive and family implications.

A clonal myeloproliferative disorder, usually driven by a JAK2 mutation that makes marrow precursors hypersensitive to growth signals, so red cells (and often white cells and platelets) are overproduced independent of erythropoietin, raising blood viscosity and thrombosis risk while erythropoietin itself is suppressed.

An inflammatory syndrome in adults over 50 causing new bilateral shoulder or pelvic-girdle pain and prolonged stiffness, diagnosed by clinical pattern and exclusion of mimics, with urgent screening for associated giant cell arteritis.

Polymyositis and dermatomyositis sit within the idiopathic inflammatory myopathies, a group of multisystem autoimmune diseases causing objective muscle weakness and sometimes characteristic skin, lung, swallowing and cardiac disease. In adults, dermatomyositis and selected antibody phenotypes also signal increased malignancy risk.

Postural hypotension is a clinically important fall in blood pressure after standing, caused by inadequate compensation for gravitational blood pooling; it presents with postural dizziness, falls or syncope and should trigger medication, volume, cardiovascular, neurological and endocrine assessment.

Non-diabetic hyperglycaemia, often called prediabetes, is glucose above the usual range but below the diagnostic threshold for diabetes; it identifies increased type 2 diabetes and cardiovascular risk and is an opportunity for intensive prevention.

Localised damage to skin and underlying tissue, usually over a bony prominence, caused by sustained pressure or pressure combined with shear; early recognition and pressure relief are the core interventions.

A framework for diagnosing migraine, tension-type headache and cluster headache clinically after screening for secondary-headache red flags and medication overuse.

Autonomous aldosterone secretion with suppressed renin, causing sodium retention, hypertension and sometimes hypokalaemia; it is a treatable cause of secondary hypertension that may be unilateral or bilateral.

Prostate cancer is often silent while confined to the peripheral zone; PSA and DRE trigger assessment, mpMRI precedes biopsy, and PSA, grade group and stage determine whether surveillance, radical treatment or systemic therapy is appropriate.

Prostatitis ranges from acute bacterial infection with systemic illness and urinary symptoms to chronic bacterial prostatitis and chronic pelvic pain syndrome; the first priorities are to recognise sepsis or retention, obtain cultures without delaying treatment, and avoid confusing non-bacterial pain with an infection that needs antibiotics.

Acute calcium pyrophosphate crystal arthritis, usually affecting an older person's knee or wrist; confirm the crystal when needed, exclude septic arthritis, and treat the flare without confusing it with urate-driven gout.

Psoriasis is a chronic immune-mediated inflammatory disease with several skin and nail phenotypes and important joint, psychological and cardiometabolic associations; severity depends on site, extent, symptoms and life impact, not redness alone.

A heterogeneous inflammatory arthritis associated with psoriasis, characterised by combinations of peripheral arthritis, axial disease, enthesitis, dactylitis and nail involvement.

A venous clot, usually from a deep leg or pelvic vein, lodges in the pulmonary arterial tree, obstructing perfusion and abruptly loading the right ventricle.

Pulmonary hypertension is a haemodynamic disorder in which the pulmonary circulation places an abnormal load on the right ventricle; diagnosis requires specialist classification because treatment differs between pulmonary arterial, left-heart, lung-disease, chronic-thromboembolic and multifactorial disease.

Radiculopathy is dysfunction of a spinal nerve root causing radiating pain, sensory change, weakness or reflex loss in a root distribution; most lumbar sciatica improves with conservative care, but cauda equina, cord compression, progressive deficit, infection and malignancy require urgent escalation.

Raised intracranial pressure is a dangerous final pathway in which increased volume within the fixed skull reduces cerebral perfusion and may cause herniation; the cause, visual risk and speed of neurological deterioration determine the emergency pathway.

Raynaud's phenomenon is episodic digital vasospasm triggered by cold or stress, causing sharply demarcated colour change, numbness and pain. Primary disease is usually benign, but later-onset, asymmetric or tissue-damaging disease may be secondary to systemic sclerosis, another connective-tissue disorder, large-vessel disease, vibration or medicines.

A sterile inflammatory arthritis that develops after a gastrointestinal or genitourinary infection and commonly follows an asymmetric spondyloarthritis pattern.

Rectal prolapse is descent of rectal tissue through or within the anal canal, ranging from internal intussusception to external full-thickness prolapse; it causes a proluding mass, mucus, bleeding, obstructed defaecation or faecal incontinence and needs urgent review if it is irreducible, dusky or heavily bleeding.

Refeeding syndrome is a potentially fatal metabolic and fluid complication of restarting nutrition in a severely malnourished or starved person; insulin shifts phosphate, potassium and magnesium into cells, while carbohydrate use can expose thiamine deficiency and sodium-water retention can cause fluid overload.

Renal cancer is usually renal cell carcinoma arising in the renal parenchyma; it is often found incidentally, while visible haematuria, venous invasion or paraneoplastic features should trigger urgent staging and uro-oncology assessment.

A ureteric stone causes severe colicky loin-to-groin pain by obstructing urine flow and triggering ureteric spasm; fever, anuria, renal impairment or a solitary kidney changes this into an urgent urological pathway.

Gas exchange fails in one of two ways: the lung cannot load oxygen into blood (type 1), or the ventilatory pump cannot clear carbon dioxide (type 2).

Skeletal muscle necrosis floods the circulation with creatine kinase, myoglobin, potassium and phosphate: myoglobin obstructs and poisons the renal tubules, while potassium can stop the heart within hours.

A systemic inflammatory synovitis that can irreversibly damage joints and organs; refer persistent synovitis urgently and start specialist-led treat-to-target DMARD therapy early.

A chronic inflammatory facial dermatosis with flushing, persistent erythema, telangiectasia, papules or pustules, phymatous change and/or ocular disease; identify the dominant feature because treatment is feature-directed.

Sarcoidosis is a multisystem inflammatory disease characterised by non-necrotising granulomas, usually involving the lungs and intrathoracic lymph nodes; management balances spontaneous remission against progressive, organ-threatening or quality-of-life-limiting disease after infection and malignancy have been excluded.

Sarcopenia is muscle failure characterised by low strength, while frailty is reduced reserve across several systems that makes a person vulnerable to disproportionate decline after a minor stressor; they commonly coexist but require different assessments.

A contagious infestation by Sarcoptes scabiei causing intense nocturnal itch, burrows and a papular rash; cure requires correct whole-body treatment and simultaneous treatment of relevant close contacts.

Assess every scrotal lump by urgency, relation to the testis, fluid versus solid character and positional behaviour; first exclude torsion and malignancy, then manage the common benign lesions according to symptoms.

Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection, in which inflammatory signalling and microvascular failure injure organs remote from the infected site.

Bacteria in the joint space trigger a neutrophil response whose enzymes digest articular cartilage within days, so the inflammation destroys the joint faster than the organism does.

Excess central serotonergic activity produces neuromuscular excitation, autonomic instability and altered mental state within hours, and the muscle activity itself generates the hyperthermia that kills.

Shingles is reactivation of latent varicella-zoster virus in a sensory ganglion, usually causing a painful unilateral dermatomal rash; treat eligible patients promptly, recognise ophthalmic, neurological and disseminated disease, manage post-herpetic neuralgia, and offer current Shingrix vaccination to eligible cohorts.

SIADH is inappropriate antidiuresis causing water retention and euvolaemic hypotonic hyponatraemia with inappropriately concentrated urine; it is a diagnosis of exclusion and management depends first on symptoms, then on the cause and risk of over-correction.

An inherited haemoglobinopathy in which deoxygenated haemoglobin S polymerises, making red cells rigid and adhesive; vaso-occlusion causes ischaemic pain while haemolysis causes chronic anaemia and progressive organ damage.

Sjogren disease is a chronic autoimmune condition causing ocular, oral and other mucosal dryness, with possible joint, skin, lung, renal, neurological and haematological involvement; persistent gland swelling or systemic features need specialist assessment because lymphoma risk is increased.

Spinal cord injury disrupts motor, sensory and autonomic pathways below a lesion; early priorities are spinal protection, oxygenation, perfusion and specialist trauma care, with neurogenic shock and autonomic dysreflexia as key emergencies.

A family of inflammatory arthritides with axial or peripheral patterns, enthesitis, dactylitis and characteristic extra-articular disease involving the eye, skin and gut.

Spontaneous bacterial peritonitis (SBP) is infection of ascitic fluid without a surgically treatable intra-abdominal source, usually in advanced cirrhosis; diagnose it promptly with ascitic neutrophil counting and treat immediately with context-appropriate antibiotics, renal-protective albumin when indicated and specialist follow-up.

ST-elevation myocardial infarction (STEMI) is acute coronary occlusion, usually thrombus on a disrupted plaque, whose injury current appears as persistent regional ST elevation in a compatible ischaemic presentation.

Stable angina is predictable myocardial ischaemic pain from supply-demand mismatch, usually due to atherosclerotic coronary disease; new, worsening or rest pain is an ACS emergency until assessed.

Convulsive status epilepticus is a self-sustaining seizure state in which gamma-aminobutyric acid (GABA) inhibition fails, so seizures no longer stop spontaneously and grow harder to treat every minute.

A life-threatening severe cutaneous adverse reaction with painful epidermal necrosis or detachment and prominent mucosal disease; treat it as a skin-failure emergency until specialist assessment excludes it.

Sudden focal neurological loss from arterial occlusion or vessel rupture: occlusion leaves a dying core around which viable brain can still be rescued, rupture makes any antithrombotic dangerous.

Arterial blood bursts into the cerebrospinal fluid around the brain, usually from a ruptured intracranial aneurysm, raising intracranial pressure and irritating the meninges within seconds. Abbreviated SAH.

Bridging veins shear between the mobile cortex and the fixed dural sinuses, bleeding beneath the dura to form a crescentic collection that crosses sutures but not the falx.

Compression, invasion or thrombosis of the superior vena cava blocks venous drainage from the head, neck and arms, raising upstream pressure until collaterals open or the airway is threatened.

A re-entry circuit running through the atrioventricular (AV) node, either within it or looping via an accessory pathway, fires at a fixed rate and gives abrupt regular narrow-complex tachycardia.

Syphilis is a sexually and vertically transmissible Treponema pallidum infection with primary, secondary, latent and late multisystem manifestations; stage accurately, recognise neurological/ocular/pregnancy complications, treat through a specialist sexual-health pathway and document serological response.

A lifelong multisystem autoimmune disease in which loss of tolerance produces autoantibodies and inflammation across skin, joints, kidneys, blood, serosa and the nervous system.

Systemic sclerosis is a multisystem autoimmune disease combining small-vessel vasculopathy, immune activation and fibrosis; it can threaten the digits, lungs, pulmonary circulation, heart, kidneys and gut, so early specialist risk stratification and structured surveillance are essential.

For an abnormal-origin tachyarrhythmia, first decide whether there is a pulse, then whether life-threatening adverse signs make the patient unstable; only a stable patient proceeds to classification by QRS width and regularity, while sinus tachycardia is treated by correcting its cause.

Pericranial myofascial nociception, with central sensitisation in chronic disease, produces a bilateral pressing headache that is mild to moderate and not worsened by routine physical activity.

Testicular cancer is usually a germ-cell tumour presenting as a persistent intratesticular mass in a young adult; urgent ultrasound, tumour markers and radical inguinal orchidectomy establish the diagnosis, while stage-directed specialist treatment achieves very high cure rates.

Rotation of the spermatic cord obstructs venous outflow and then arterial inflow, so the testis infarcts within hours unless it is surgically untwisted.

Tetanus is a rare but life-threatening neurological disease caused by tetanospasmin from Clostridium tetani in a wound; recognise it clinically, give urgent hospital treatment and post-exposure prophylaxis according to the current UKHSA wound algorithm, and prevent it with the five-dose vaccine schedule.

Thalassaemia is an inherited disorder of reduced alpha- or beta-globin synthesis causing ineffective erythropoiesis, haemolysis and microcytic anaemia; severity ranges from an asymptomatic carrier state to transfusion-dependent disease with lifelong risk from iron overload.

Thrombophilia is an inherited or acquired tendency to thrombosis. Testing is selective because most heritable results do not change anticoagulation decisions, whereas antiphospholipid syndrome can alter the choice of anticoagulant, pregnancy management and long-term follow-up.

Toxic megacolon is acute non-obstructive colonic dilatation accompanied by systemic toxicity, usually complicating acute severe ulcerative colitis or severe infection such as C. difficile; it is a time-critical colorectal emergency because the inflamed colon can perforate.

Toxic shock syndrome is a rapidly progressive toxin-mediated illness caused by Staphylococcus aureus or group A Streptococcus, with fever, diffuse rash, hypotension and multi-organ dysfunction; treat it as an emergency with sepsis resuscitation, immediate source control and specialist antimicrobial therapy.

Toxoplasma gondii infection is usually asymptomatic or mild in immunocompetent people, but needs specialist management when it affects the eye, brain, pregnancy or fetus; keep these pathways separate.

Blood components injure recipients four separate ways, immune destruction of red cells, plasma-protein allergy, bacterial contamination and sheer transfused volume, and at onset they look alike.

A transient focal neurological syndrome caused by cerebral, spinal or retinal ischaemia without acute infarction; symptoms may resolve quickly, but the event is a medical warning that requires immediate aspirin and specialist assessment within 24 hours.

Trichomoniasis is a sexually transmitted infection caused by Trichomonas vaginalis; it is often asymptomatic, but may cause vaginitis or urethritis, and diagnosis requires appropriate laboratory testing followed by systemic treatment and partner management.

Trigeminal neuralgia causes recurrent, brief, severe electric-shock-like facial pain triggered by innocuous stimuli; diagnose the phenotype clinically, investigate atypical or secondary features, offer carbamazepine first-line and refer early when treatment fails or procedures may be needed.

A chronic Mycobacterium tuberculosis complex infection that may remain latent or reactivate as active pulmonary or extrapulmonary disease, requiring microbiological diagnosis, multi-drug treatment and public-health contact tracing.

A sex-chromosome condition caused by complete or partial loss of one X chromosome, usually 45,X or mosaic, with variable short stature, ovarian insufficiency and characteristic cardiac, renal, hearing, metabolic and learning needs; aortic disease makes lifelong cardiovascular care essential.

An autoimmune disease that destroys pancreatic beta cells until insulin secretion fails almost completely, so glucose rises unchecked and unopposed lipolysis drives ketone production: the mechanism behind both the presentation and the risk of diabetic ketoacidosis.

Progressive hyperglycaemia caused by insulin resistance with relative beta-cell failure; safe care treats acute metabolic decompensation, cardiorenal risk and complications as well as glucose.

A chronic inflammatory colitis that usually begins in the rectum and extends continuously proximally, producing bloody diarrhoea and urgency; severity determines whether the pathway is outpatient induction, specialist escalation or acute severe colitis admission.

Unstable angina is acute coronary ischaemia that causes rest or crescendo pain but stops short of killing myocytes, so troponin never rises and falls diagnostically.

Bleeding above the ligament of Treitz, where the lesion (an acid-eroded artery or a ruptured portal-hypertensive varix) decides which of two entirely different drug pathways the patient needs.

Urinary incontinence is involuntary urine leakage; the pattern—effort-related, urgency-related, mixed, continuous or dribbling from retention—identifies the mechanism and determines whether pelvic-floor training, bladder training, medicines, catheterisation or specialist treatment is appropriate.

Urinary retention is failure to empty the bladder: acute retention is usually painful and needs prompt drainage, while chronic retention may be painless but can cause overflow, hydronephrosis and acute kidney injury, so the cause, residual volume and upper-tract risk determine urgency.

Diagnose UTI from the clinical syndrome and appropriate urine testing, distinguish lower infection from pyelonephritis and sepsis, and tailor antibiotics to age, pregnancy, renal function, culture and local resistance.

Mast-cell mediator release causes short-lived, itchy, blanching weals; histaminergic angioedema and anaphylaxis can accompany urticaria, while isolated angioedema may instead be bradykinin-mediated and needs a different pathway.

Valvular heart disease presents through murmurs, symptoms or imaging; identify severity, urgency, mechanism and the need for specialist valve-team review.

A varicocoele is dilated pampiniform venous plexus, usually left-sided and benign; treatment is not automatic and is considered mainly for selected fertility, pain or adolescent testicular-development indications.

Vasculitis is a group of disorders in which vessel-wall inflammation causes ischaemia, aneurysm or haemorrhage; vessel size and the organ pattern guide diagnosis, urgency and treatment.

Ventricular fibrillation is chaotic, disorganised ventricular electrical activity that produces no coordinated contraction, so the circulation stops and the patient is in cardiac arrest.

Ventricular tachycardia (VT) arises in ventricular myocardium below the His bundle, so activation spreads slowly cell to cell, widening the QRS complex and desynchronising ventricular contraction.

Infection and inflammation of the liver caused by hepatitis A, B, C, D or E, ranging from self-limiting acute illness to chronic infection with cirrhosis, liver failure and hepatocellular carcinoma.

Volvulus is twisting of bowel around its mesentery, causing a closed-loop obstruction and threatening the blood supply; sigmoid volvulus may be detorted endoscopically when uncomplicated, whereas caecal and paediatric midgut volvulus generally require urgent surgical management.

Von Willebrand disease is an inherited quantitative or qualitative defect of von Willebrand factor, impairing platelet adhesion and factor VIII stability and causing predominantly mucocutaneous bleeding; treatment depends on the subtype, bleeding phenotype, procedure and a documented response plan.

Wernicke-Korsakoff syndrome is a spectrum of thiamine deficiency: acute Wernicke's encephalopathy is a treatable medical emergency, while Korsakoff's syndrome is a chronic amnesic disorder requiring abstinence support, rehabilitation and tailored long-term care.

An abdominal aortic aneurysm (AAA) is a focal abdominal-aortic dilatation that is often silent until it becomes symptomatic or ruptures; management is determined by symptoms, diameter, growth, anatomy, operative risk and patient preference.

A sudden obstruction of aqueous outflow causes a rapidly painful rise in intraocular pressure, producing a red eye with visual symptoms and vomiting that needs same-day ophthalmology treatment.

Acute inflammation of the appendix usually causes migrating abdominal pain and right iliac fossa peritonism, but atypical presentations and complications require early senior assessment, targeted imaging and timely source control.

Persistent cystic-duct obstruction inflames the gallbladder rather than causing transient biliary colic: assess for sepsis and common-bile-duct disease, give supportive and antimicrobial treatment when indicated, and arrange early source control.

Sudden arterial occlusion cuts limb perfusion faster than collaterals can compensate, so nerve and then muscle fail within hours and the limb is lost unless flow is restored.

Sudden loss of blood supply to the small bowel, most often an embolus from the heart lodging in the superior mesenteric artery, causes rapidly progressive transmural infarction; the hallmark is severe pain out of proportion to a soft abdomen, and survival depends on revascularising the gut before it dies.

A usually self-limiting middle-ear infection in children, diagnosed by the clinical picture and otoscopy; analgesia and safety-netting come first, with antibiotics reserved for children more likely to benefit or at higher risk.

Inflammation of the nasal mucosa and paranasal sinuses that follows blockage of their narrow drainage pathways, almost always viral and self-limiting, with antibiotics reserved for the minority who develop true bacterial superinfection or complications.

Age-related macular degeneration damages the macula and therefore central vision; suspected late wet active AMD needs urgent macular-service referral, OCT and prompt anti-VEGF treatment, while dry AMD needs risk-factor advice, self-monitoring, low-vision support and clear safety-netting.

An anal fissure is a painful anoderm tear, usually posterior midline; relieve constipation and sphincter spasm, and investigate atypical or refractory disease for secondary causes.

Ankle-fracture management is driven by skin and neurovascular status, mortise stability and patient factors: urgent reduction for deformity, appropriate radiographs and CT for complex patterns, weight-bearing treatment for stable injuries, and timely fixation or specialist non-operative care for unstable injuries.

Inflammation of the iris and ciliary body causing a painful photophobic red eye; it needs urgent ophthalmic assessment because early treatment prevents synechiae and sight-threatening complications.

Bacteria multiply in bile trapped behind an obstructed common bile duct, and rising pressure in the duct drives them into the bloodstream.

Brief, position-triggered vertigo caused by displaced otoconia in a semicircular canal; diagnose with positional testing and treat posterior-canal disease with a canalith-repositioning manoeuvre.

Blepharitis is chronic inflammation of the eyelid margins: anterior disease affects the lash line, while posterior disease is usually meibomian gland dysfunction. It causes sore, gritty, crusted lids and evaporative dry-eye symptoms; long-term lid hygiene is the foundation, while pain, visual change or a very red eye needs urgent assessment for another ocular diagnosis.

Bowel obstruction stops intestinal contents passing, so gas and fluid pile up above the block. The distended bowel leaks litres into its own lumen and can strangle its own blood supply.

A full-thickness breach of the gut wall spills gas and enteric contents into a sterile cavity, so chemical irritation is followed by bacterial peritonitis and sepsis.

A malignant tumour of breast epithelium whose diagnosis, prognosis and treatment depend on whether it is in situ or invasive, its stage, grade and ER, PR and HER2 profile.

Heat, chemicals or electricity destroy skin and drive an inflammatory capillary leak, so a burn threatens the airway, the circulating volume and, when circumferential, ventilation and limb perfusion.

Atherosclerotic carotid stenosis can embolise to the retina or ipsilateral cerebral circulation; recent carotid-territory TIA or non-disabling stroke makes the lesion time-critical, with urgent imaging, best medical treatment and selected carotid endarterectomy.

Progressive opacification of the crystalline lens scatters and blocks incoming light, causing gradual, painless blurring of vision that only surgery (replacing the lens) can reverse, because the damaged protein structure cannot be cleared or treated medically.

Acute or rapidly progressive compression of the lumbosacral nerve roots below the spinal cord, threatening permanent loss of bladder, bowel, sexual and lower-limb function unless decompressed urgently.

Central retinal artery occlusion is an ocular stroke causing sudden, painless monocular visual loss; it needs immediate stroke and ophthalmology assessment, with urgent exclusion and treatment of giant cell arteritis when clinically suspected.

Central retinal vein occlusion causes sudden or subacute painless unilateral visual loss with widespread retinal haemorrhages and macular oedema; distinguish non-ischaemic from ischaemic disease because ischaemia carries a high risk of iris/angle neovascularisation and neovascular glaucoma.

Cholesteatoma is a self-renewing collection of keratinising squamous epithelium in the middle-ear cleft or mastoid that can erode bone, damage hearing and spread infection; it is not a tumour and needs specialist ENT assessment.

Chronic open-angle glaucoma is progressive optic-nerve damage with an open drainage angle and corresponding visual-field loss; it is usually painless and peripheral vision is lost first, so diagnosis depends on structured testing and treatment aims to prevent further irreversible loss.

Colorectal cancer is usually an adenocarcinoma of the colon or rectum whose presentation, local treatment and chance of cure depend on site, TNM stage and tumour biology; FIT helps select symptomatic patients for referral but cannot safely rule cancer out when clinical concern persists.

Rising pressure inside a closed fascial compartment collapses the capillary perfusion gradient, so muscle and nerve die while the major artery stays patent and the distal pulse stays palpable.

Fracture complications range from immediate haemorrhage, neurovascular injury and compartment syndrome to later infection, venous thromboembolism and failure of union; serial assessment and rapid specialist escalation are the safety-critical skills.

A superficial red, gritty, itchy or discharging eye caused by infection, allergy or irritation; preserved vision and a comfortable cornea support the diagnosis, while pain, photophobia, reduced vision, contact-lens use or neonatal disease needs urgent escalation.

A corneal abrasion is a traumatic defect of the corneal epithelium causing severe pain, watering and photophobia; confirm it with fluorescein, exclude a foreign body or open-globe injury, and treat contact-lens-associated abrasions as higher-risk for microbial keratitis.

Diabetes damages retinal microvasculature, progressing from non-proliferative disease to ischaemia-driven neovascularisation, while diabetic macular oedema is a separate sight-threatening pathway; screening and stage-specific ophthalmic treatment prevent avoidable visual loss.

Diverticulosis means asymptomatic colonic diverticula, diverticular disease means symptoms without systemic inflammation, and acute diverticulitis is sudden inflammation or infection that may be uncomplicated or complicated by abscess, perforation, fistula, stricture, obstruction or sepsis; diverticular bleeding is often a separate painless presentation.

Epiglottitis or supraglottitis is acute swelling around the laryngeal inlet that can obstruct the airway rapidly; keep the person calm and upright, avoid throat manipulation, call senior anaesthetic and ENT help and secure the airway before tests or routine treatment.

Episcleritis is usually self-limiting inflammation of the superficial episclera, causing a sectoral or diffuse red eye with mild aching and preserved vision; its key clinical task is to exclude the painful, potentially sight-threatening deep inflammation of scleritis.

Nasal bleeding is usually anterior and responds to correct pressure, but heavy, posterior or recurrent bleeding needs structured assessment, packing and ENT escalation.

Abdominal contents push through the narrow, rigid femoral canal below and lateral to the pubic tubercle, and because that canal is tighter and less compliant than the inguinal canal, femoral hernias carry a much higher risk of strangulation and are treated as surgical emergencies until proven otherwise.

A benign fibroepithelial breast lesion, usually presenting in adolescents or young adults as a smooth, firm, mobile lump; diagnosis depends on concordant clinical and imaging assessment, with biopsy or excision when the pattern is atypical.

Gallstones are often silent; when a stone transiently obstructs the cystic duct, it causes biliary colic, while persistent or downstream obstruction produces cholecystitis, jaundice, cholangitis or pancreatitis.

Gastric cancer is usually adenocarcinoma: early disease can be subtle, while alarm symptoms should trigger a current NICE suspected-cancer pathway, biopsy-based diagnosis, whole-body CT and specialist MDT staging before treatment is selected by resectability and tumour biology.

Haemorrhoids are symptomatic anal cushions causing bleeding, prolapse, itching or pain; do not assume rectal bleeding is haemorrhoidal without appropriate examination and cancer-pathway judgement.

Head and neck cancer is usually a squamous cell carcinoma of the upper aerodigestive tract; persistent hoarseness, oral ulceration, dysphagia, unilateral otalgia or an unexplained neck lump needs prompt specialist assessment, with urgent escalation for airway compromise or major bleeding.

A hiatus hernia is upward displacement of stomach through the oesophageal hiatus; sliding hernia can impair the reflux barrier, while para-oesophageal or mixed hernia can cause early satiety, bleeding, obstruction or volvulus, so treatment is driven by symptoms, complications, anatomy and operative risk.

Infective keratitis is a sight-threatening corneal infection causing a painful red photophobic eye with an infiltrate or ulcer; contact-lens-associated disease and Acanthamoeba require emergency ophthalmology, microbiological assessment and specialist antimicrobial treatment.

A groin-wall defect allows fat or bowel to protrude through the inguinal canal; the key clinical decisions are whether it is reducible, whether it is symptomatic, and whether obstruction or strangulation makes it an emergency.

Inadequate blood supply to the gut, spanning three entities that differ in vessel, tempo and danger: acute mesenteric ischaemia (a small-bowel emergency), chronic mesenteric ischaemia (intestinal angina from symptomatic mesenteric arterial disease), and ischaemic colitis (usually a low-flow colonic injury); telling them apart drives urgency.

A fall in colonic perfusion below what the mucosa needs, striking hardest at the watershed zones where two arterial territories barely overlap, so the splenic flexure suffers first and the resulting mucosal injury produces the classic pairing of left-sided pain and bloody diarrhoea.

Mastitis is breast inflammation on a spectrum from lactational inflammation to bacterial infection; a breast abscess is a drainable collection that needs urgent ultrasound assessment and drainage, while persistent or non-lactational inflammation needs a clear malignancy safety-net.

Acute mastoiditis is serious infection extending from the middle ear into the mastoid air cells; a painful red post-auricular swelling with pinna displacement is an ENT emergency because infection can form an abscess or spread to the facial nerve, venous sinuses or intracranial space.

Ménière's disease is a disorder of the inner ear causing recurrent spontaneous vertigo attacks lasting minutes to hours, with fluctuating hearing loss, tinnitus and aural pressure; diagnosis is specialist and other vestibular, neurological and retrocochlear causes must be considered.

Nasal polyps are soft oedematous inflammatory growths that usually occur bilaterally and cause nasal obstruction and reduced smell; a unilateral or bloody/atypical mass is a different problem until ENT assessment excludes tumour or another local lesion.

A hip fracture is an orthogeriatric emergency: image promptly, control pain, correct reversible physiology without avoidable delay, and operate on the day of or day after admission with the operation matched to the fracture pattern and pre-fracture function.

Progressive dysphagia is an urgent cancer symptom: confirm oesophageal cancer with endoscopy and biopsy, stage it with CT and selected PET-CT, EUS or laparoscopy, then use histology, stage, fitness and MDT review to guide curative or palliative treatment.

Optic neuritis is inflammation of the optic nerve causing subacute visual loss, impaired colour vision, a relative afferent pupillary defect and often pain on eye movement; it needs urgent eye assessment and may be the first presentation of multiple sclerosis or antibody-mediated disease.

Inflammation or infection of the external auditory canal, usually managed with ear care, analgesia and topical treatment; severe persistent pain in a person with diabetes or immunosuppression is a necrotising otitis externa emergency.

Papilloedema is optic-disc swelling caused by raised intracranial pressure; it is a sign rather than a diagnosis and needs urgent confirmation, brain imaging with venous imaging and specialist management to prevent irreversible visual loss or neurological deterioration.

A tympanic-membrane perforation is a hole caused most often by acute otitis media, direct trauma or pressure change; most heal spontaneously, so keep the ear dry, avoid instrumentation and unprescribed drops, and refer persistent, infected or complicated perforations.

Blockage of a mucus-secreting anal gland lets bacteria multiply into a walled-off abscess, and if that pus tracks a path to the skin before it is drained, the epithelialised tunnel it leaves behind becomes a persistent fistula-in-ano.

Peripheral arterial disease (PAD) is a manifestation of systemic atherosclerosis in which lower-limb arterial flow cannot meet demand, causing intermittent claudication or, when tissue perfusion is inadequate at rest, chronic limb-threatening ischaemia.

Bacteria or gut contents reach the peritoneal cavity, which cannot clear them, so infection spreads across its huge surface and drives ileus, third-space fluid loss and sepsis.

A collection of pus between the tonsil capsule and the pharyngeal muscles (quinsy), forming when tonsillitis spreads beyond the tonsil into an adjacent tissue plane, producing trismus and a muffled voice that mark it out as a surgical emergency rather than severe tonsillitis.

Retinal detachment separates the neurosensory retina from its support tissues and can cause permanent sight loss; new flashes, floaters, a curtain or sudden visual loss need urgent retinal assessment, especially before the macula detaches.

A scaphoid fracture after a fall onto an outstretched hand can be occult on initial radiographs; immobilise clinical suspicion, obtain definitive imaging promptly, and escalate proximal or displaced injuries because retrograde blood supply makes non-union and avascular necrosis clinically important.

Scleritis is severe inflammation of the sclera causing deep eye pain, a dark red or violaceous tender eye and possible visual loss; it is an ophthalmic emergency because necrotising or posterior disease can destroy the eye and may reveal systemic autoimmune, vasculitic or infectious disease.

A traumatic glenohumeral dislocation is usually anterior after a fall onto an abducted, externally rotated arm; urgent controlled reduction depends on pre- and post-reduction neurovascular assessment and imaging, followed by rehabilitation and recurrence-risk review.

Subconjunctival haemorrhage is a superficial bleed beneath the conjunctiva causing a sharply demarcated bright-red patch with normal vision; it is usually harmless, but pain, visual change or trauma means the diagnosis must be reconsidered urgently.

The acute abdomen is a high-risk presentation rather than a diagnosis: assess physiology, pregnancy and surgical red flags in parallel with analgesia, targeted tests and imaging, then obtain early senior review and source control when needed.

Thyroid nodules are common and usually benign; assess a clinically concerning lump with thyroid function tests, greyscale ultrasound and ultrasound-guided FNAC when the established ultrasound threshold is met, then manage cytology and cancer by risk and subtype.

Acute sore-throat inflammation involving the tonsils, usually viral and self-limiting; clinical scoring targets antibiotics to people more likely to benefit while airway compromise, quinsy and deep-neck infection require urgent escalation.

Varicose veins are superficial veins made tortuous by venous reflux; symptoms, skin change, ulceration, bleeding or thrombosis determine referral, with duplex-guided intervention preferred over routine compression hosiery when treatment is suitable.

Vestibular neuritis causes an acute vestibular syndrome of prolonged vertigo, nausea and imbalance without hearing loss; labyrinthitis adds hearing loss and/or tinnitus, but both diagnoses are made only after urgent assessment for posterior-circulation stroke and other dangerous causes.

Bleeding from or into the genital tract from 24+0 weeks until birth, where the visible loss understates the true loss and two patients are bleeding at once.

Bacterial vaginosis is a vaginal microbiome syndrome causing thin, grey-white, fishy-smelling discharge with little inflammation; diagnosis is clinical or microscopy-supported, and current UK care prioritises symptomatic treatment, pregnancy assessment, STI exclusion and specialist management of recurrence.

Persistent high-risk HPV infection can cause cervical precancer and invasive cancer; England's screening programme uses primary hrHPV testing with cytology triage, while symptoms or a suspicious cervix require direct clinical assessment and specialist staging.

Suspected intra-amniotic infection is usually an ascending infection associated with ruptured membranes; it can cause maternal sepsis, fetal compromise and early-onset neonatal infection, so prompt senior assessment, antibiotics and a birth plan are required.

Ectopic pregnancy is implantation outside the uterine cavity, usually in a fallopian tube, a structure that cannot expand, so trophoblastic invasion ends in rupture and intraperitoneal haemorrhage.

Endometrial cancer usually presents with abnormal uterine bleeding, especially postmenopausal bleeding; prompt referral, histological diagnosis, MMR and molecular assessment, and risk-adapted gynaecological oncology treatment are the key steps.

Endometriosis is endometrium-like tissue outside the uterine cavity that causes inflammation, pain and fibrosis; suspect it from period-related pelvic, bowel, urinary or sexual symptoms, investigate and treat in parallel, and tailor decisions to pain, fertility and disease location.

Gestational diabetes is pregnancy-related hyperglycaemia diagnosed by risk-factor-based OGTT when maternal insulin secretion cannot compensate for placental insulin resistance; treatment aims to reduce fetal overgrowth and neonatal hypoglycaemia while protecting maternal and fetal safety.

Hyperemesis gravidarum is severe nausea and vomiting of early pregnancy that prevents normal eating and drinking and limits daily function; assess clinically for dehydration, weight loss, electrolyte disturbance and alternative diagnoses, then escalate antiemetics and fluids through community, ambulatory or inpatient care.

Intrahepatic cholestasis of pregnancy causes pruritus without a primary rash and raised bile acids, usually late in pregnancy; peak bile acids stratify stillbirth risk and guide shared decisions about monitoring and planned birth.

A chronic inflammatory dermatosis that usually affects anogenital skin, causing itch, soreness, white fragile plaques and scarring; recognise suspicious change because vulval lichen sclerosus carries a small but important risk of squamous cell carcinoma.

Menopause is the transition caused by declining ovarian follicular activity and fluctuating or low oestrogen; diagnose typical cases clinically, then tailor symptom treatment, HRT risks, contraception, bone health and follow-up to the person's stage and comorbidities.

Miscarriage is the spontaneous loss of a pregnancy before 24 weeks; this chapter focuses on early pregnancy loss, where ultrasound, clinical stability and the amount of tissue passed determine diagnosis, urgency and management.

Twin and triplet pregnancy is higher risk than singleton pregnancy; early determination of chorionicity and amnionicity drives surveillance, fetal-medicine referral, preterm-birth prevention and timing and mode of birth.

Ovarian, fallopian-tube and primary peritoneal cancers are closely related diseases that often spread across the peritoneum before causing obvious local symptoms; persistent or frequent bloating, early satiety, pelvic or abdominal pain and urinary symptoms need the current NICE symptom-triggered testing pathway.

An ovarian cyst is a fluid-filled sac in or on the ovary; most in premenopausal women are functional and resolve spontaneously, so the clinical task is to separate these benign cysts from the minority that are complications (torsion, rupture) or malignant, using menopausal status, ultrasound morphology and CA125.

Twisting of the ovary and tube on their vascular pedicle occludes venous outflow first and then arterial inflow, so the ovary congests and infarcts.

Pelvic organ prolapse is descent of the bladder, uterus, rectum or vaginal vault into or through the vagina because the pelvic floor muscles and fascia that support them have weakened; it is common after childbirth and around the menopause, and management runs from pelvic floor training and pessaries to surgery.

Placental tissue lying over the internal cervical os shears as the lower uterine segment forms, opening maternal vessels and causing painless recurrent bleeding from a segment that then contracts poorly.

Premature separation of a normally sited placenta: decidual bleeding strips the placenta off the uterine wall, so pain, hypertonus, fetal hypoxia and coagulopathy appear with almost no visible blood.

Polycystic ovary syndrome is a heterogeneous endocrine, metabolic and reproductive condition characterised by ovulatory dysfunction and hyperandrogenism, with polycystic ovarian morphology in some people; diagnose by the appropriate criteria, exclude mimics and manage reproductive, metabolic, psychological and endometrial risks together.

Postpartum haemorrhage is bleeding after birth that outruns the myometrial contraction meant to close the placental bed, usually from atony, retained tissue, trauma or failed clotting.

A placental disease of the second half of pregnancy: shallow placentation injures the maternal endothelium, so new hypertension after 20 weeks arrives with kidney, liver, brain, platelet or fetal damage.

Preterm labour is suspected or established labour before 37 weeks; management aims to identify true imminent birth, gain safe time for corticosteroids, magnesium neuroprotection and in-utero transfer, and avoid delaying birth when infection, bleeding or fetal compromise makes delivery safer.

Rhesus disease is haemolytic disease of the fetus and newborn caused by maternal IgG alloantibodies crossing the placenta and destroying fetal red cells carrying the corresponding antigen; anti-D disease is largely preventable, whereas established sensitisation requires specialist fetal and neonatal surveillance.

Shoulder dystocia is impaction of a fetal shoulder against the maternal pelvis after the head has delivered, so the shoulders will not follow routine axial traction.

Umbilical cord prolapse is descent of the cord past or alongside the presenting part after membrane rupture, so the presenting part and contractions compress it and fetal oxygenation fails.

Benign uterine smooth-muscle tumours that may be asymptomatic or cause heavy menstrual bleeding, pain, pressure symptoms and fertility problems; management depends on symptoms, fibroid anatomy and reproductive wishes.

Unprotected fetal vessels run through the membranes over or close to the internal cervical os; if the membranes rupture, the vessels can tear and cause rapid fetal exsanguination.

Pregnancy and the puerperium increase venous thromboembolism risk through hypercoagulability, venous stasis and vascular injury; suspected deep-vein thrombosis or pulmonary embolism needs prompt objective testing and therapeutic low-molecular-weight heparin unless strongly contraindicated.

Malignancy of the vulva, most often a squamous cell carcinoma arising either from HPV-related intraepithelial neoplasia in younger women or from long-standing lichen sclerosus in older women; it presents with a vulval lump, ulcer, persistent itch or bleeding, and delayed presentation is common because women do not report symptoms.

Biliary atresia is progressive obliteration of the extrahepatic bile ducts causing neonatal cholestasis; persistent jaundice with pale stools or dark urine needs prompt split bilirubin testing and urgent specialist referral because early surgery offers the best chance of preserving the native liver.

An acute viral small-airway infection in babies and young children causing coryza, cough, tachypnoea, wheeze or crackles and feeding difficulty; treatment is supportive, with escalation driven by work of breathing, hydration, apnoea and oxygenation.

Cerebral palsy is a permanent disorder of movement and posture attributed to a non-progressive disturbance in the developing brain; the neurological lesion is static, but tone-related musculoskeletal problems and associated impairments require proactive, lifelong multidisciplinary care.

Primary varicella-zoster infection causes successive crops of itchy vesicles that crust, then establishes lifelong latency in sensory ganglia and can later reactivate as shingles.

Childhood cancer is uncommon but can present through subtle, non-specific symptoms; a palpable abdominal mass, unexplained enlarged abdominal organ, visible haematuria or an absent fundal red reflex should trigger the appropriate urgent UK referral pathway.

A febrile child with a widespread rash needs pattern recognition, a rapid safety screen, infection-control action and targeted public-health management rather than rash-description alone.

Childhood hip disorders present through age-specific mechanisms: developmental dysplasia in infancy, Perthes disease in the school-age child and slipped upper femoral epiphysis in adolescence; all can present as a limp or referred knee pain.

Cow's milk protein allergy is an immune-mediated reaction to milk proteins in infancy, either immediate and IgE-mediated or delayed and non-IgE-mediated; diagnosis depends on an allergy-focused history and, for non-IgE disease, a supported elimination and reintroduction plan.

A usually viral upper-airway infection causing subglottic swelling and a barking cough, hoarse voice and inspiratory stridor; keep the child calm, give steroid treatment when indicated, and treat stridor at rest or deterioration as an airway emergency.

Cryptorchidism is failure of one or both testes to lie in the scrotum; persistent extrascrotal testes carry fertility, malignancy and torsion risks, so current NHS screening requires timely examination, referral and specialist orchidopexy planning.

Developmental dysplasia of the hip (DDH) is a spectrum from a shallow acetabulum through instability and subluxation to dislocation; early recognition and a stable, concentric hip position allow the socket and femoral head to develop together.

Developmental milestones are approximate age-linked skills across several domains; the clinically important task is to assess the child's trajectory, pattern and examination, then act promptly on regression, sustained developmental arrest or guideline-defined referral thresholds.

Faltering growth is a concerning change in a child's growth trajectory, usually weight first; the commonest mechanism is inadequate intake, so accurate serial measurements, feeding observation and whole-child assessment come before indiscriminate investigations.

A seizure occurring with fever in a young child without evidence of CNS infection or another acute cause; most are brief and self-limiting, but the priority is seizure safety, assessment of the febrile illness and recognition of meningitis, prolonged, focal or recurrent seizures.

IgA immune-complex small-vessel vasculitis causes palpable purpura with variable joint, gastrointestinal and renal disease; the visible rash usually settles, but renal surveillance determines long-term safety.

A segment of bowel telescopes into the adjacent segment, dragging its mesentery with it and causing intermittent obstruction, venous congestion, ischaemia and potentially perforation; prompt paediatric-surgical assessment is essential.

An acute systemic medium-vessel vasculitis in childhood with persistent fever and mucocutaneous features; it is a time-critical diagnosis because coronary artery inflammation can lead to aneurysm, thrombosis and myocardial ischaemia.

A highly contagious morbillivirus infection causing fever, cough, coryza, conjunctivitis, Koplik spots and a cephalocaudal maculopapular rash, requiring immediate isolation and public-health action.

Mesenteric adenitis is reactive inflammation of mesenteric lymph nodes, often after a viral illness, causing abdominal pain that can mimic appendicitis; it is a diagnosis reached after safe clinical exclusion and observation rather than by enlarged nodes alone.

Mumps is an acute mumps-virus infection classically causing painful parotid swelling; it remains vaccine-preventable and notifiable in England, and complications such as meningitis, orchitis, pancreatitis or hearing loss need active assessment.

Necrotising enterocolitis (NEC) is acquired ischaemic and inflammatory necrosis of the immature neonatal bowel, in which bacterial gas tracks into the bowel wall and portal veins and necrosis perforates.

Jaundice is common in newborns, but its timing, bilirubin fraction, rate of rise and effect on the baby distinguish physiological jaundice from haemolysis, sepsis, cholestatic liver disease and bilirubin neurotoxicity.

Neuroblastoma is an embryonal tumour of sympathetic neural-crest tissue, usually adrenal or paraspinal, with behaviour ranging from spontaneous regression in selected infants to aggressive metastatic disease; a child with an abdominal mass and systemic or neurological features needs urgent specialist assessment.

Suspected inflicted injury is a safeguarding and clinical emergency when the injury, account, timing or developmental stage do not fit; act on serious concern without waiting to prove abuse.

Perthes disease is childhood osteonecrosis of the femoral head caused by interrupted blood supply; the vulnerable head can deform during fragmentation, so preserving hip movement and containment during growth is central to care.

Progressive hypertrophy of the pyloric muscle causes gastric-outlet obstruction in a young infant, producing worsening non-bilious vomiting and dehydration; fluid and electrolyte correction must precede pyloromyotomy.

Retinoblastoma is a malignant retinal tumour of early childhood, usually signalled by leukocoria or strabismus; an absent fundal red reflex needs urgent specialist ophthalmological assessment because early treatment can save life, the eye and vision.

Usually mild rubella causes a fine maculopapular rash and posterior lymphadenopathy, but infection in early pregnancy can cause congenital rubella syndrome, making prevention and urgent pregnancy assessment central.

A toxin-mediated group A streptococcal infection causing fever, sore throat, a fine sandpaper rash and strawberry tongue, treated with antibiotics and public-health exclusion.

Slipped upper femoral epiphysis (SUFE/SCFE) is displacement through the proximal femoral growth plate, usually around adolescence; suspected disease requires non-weight-bearing and urgent paediatric orthopaedic stabilisation.

Fever is a common, non-specific response that ranges from self-limiting viral illness to life-threatening sepsis; structured assessment of airway, breathing, circulation, behaviour, hydration, age and source of infection determines urgency.

Pertussis is a highly contagious Bordetella pertussis infection causing prolonged paroxysmal cough; young infants may present with apnoea or cyanosis rather than a whoop and are at greatest risk of severe disease.

Wilms tumour (nephroblastoma) is an embryonal kidney cancer of childhood, usually presenting with a painless abdominal mass but sometimes haematuria or hypertension; urgent specialist referral and protocol-led treatment aim to cure while preserving renal function.

A chronic alcohol-use disorder in which neuroadaptation, impaired control and continued drinking despite harm create a potentially dangerous withdrawal syndrome when alcohol is reduced or stopped.

An eating disorder in which restriction driven by fear of weight gain and disturbed body image causes significantly low weight, starvation physiology and potentially life-threatening medical instability.

ADHD is a neurodevelopmental disorder characterised by persistent, developmentally excessive inattention and/or hyperactivity-impulsivity that began in childhood, is present across settings and causes functional impairment.

Autism is a lifelong neurodevelopmental difference involving persistent social-communication and interaction differences together with restricted, repetitive patterns of behaviour, interests or activities, present from the early developmental period and associated with support needs or functional impact.

An eating disorder with recurrent binge episodes, loss of control and marked distress, without regular compensatory behaviours; body weight varies and is not a diagnostic shortcut or the primary therapy target.

A recurrent mood disorder defined by episodes of mania or hypomania, often with depression, requiring urgent risk assessment, polarity-specific treatment and long-term relapse prevention.

An eating disorder with recurrent binge episodes, loss of control and regular compensatory behaviour, often at a normal weight but with potentially dangerous electrolyte, cardiac, dental and gastrointestinal complications.

An acute, fluctuating disturbance of attention and awareness caused by an underlying illness, substance effect or withdrawal: treat it as a medical syndrome until the cause is found.

Delusional disorder is a primary psychotic disorder in which one or more thematically related delusions remain the dominant feature, typically for at least 3 months, while prominent schizophrenia symptoms, mood episodes, substances and medical causes have been excluded and functioning outside the delusional system is relatively preserved.

A clinically diagnosed disorder of mood, interest, cognition, energy and function in which severity, suicide risk, bipolar history and patient preference determine the treatment pathway.

A framework for recognising restrictive, bingeing and compensatory eating patterns, identifying medical and psychiatric emergencies, and matching the person to specialist, diagnosis-specific treatment.

Persistent, difficult-to-control worry across multiple areas of life, with physical and cognitive symptoms causing distress or impairment, managed using a NICE stepped-care pathway.

A disorder of intrusive obsessions and repetitive compulsions that briefly reduce distress but maintain the cycle and impair daily life.

Panic disorder is recurrent unexpected panic attacks followed by at least a month of persistent concern or maladaptive behavioural change, with ongoing functional impact and no better physical, substance-related or mental-health explanation.

A trauma-related disorder characterised by re-experiencing, avoidance, threat arousal and negative changes in mood or thinking that impair recovery and daily functioning.

Postpartum psychosis is a rapidly evolving severe mental illness, usually beginning in the first 2 weeks after birth, with psychotic and affective symptoms that require immediate specialist assessment, urgent risk management and usually inpatient treatment.

Schizoaffective disorder is a specialist psychotic disorder in which schizophrenia symptoms and a clinically significant mood episode occur in the same illness; diagnosis depends on the classification system and a reliable time course, so psychosis, mood, risk, medical causes and treatment response must all be assessed longitudinally.

A psychotic disorder diagnosed through longitudinal assessment of persistent psychosis, functional change and exclusion of mood, substance-related and medical causes, requiring urgent risk management and coordinated long-term care.

Intentional self-poisoning or self-injury irrespective of apparent purpose, requiring concurrent physical care, compassionate psychosocial assessment, individualised safety planning and coordinated aftercare.