Gastroenterology & Nutrition

Premature activation of the pancreas's own digestive enzymes causes it to digest itself, so the pain, the systemic inflammatory response and the organ failure it can trigger are all consequences of autodigestion, not infection.

A dose- and time-dependent spectrum from reversible fatty change through inflammation to irreversible scarring, so the stage a patient is at determines whether stopping alcohol can still reverse the damage.

An immune reaction to dietary gluten that flattens the small-bowel villi, so the clinical picture is the predictable consequence of losing absorptive surface, and the treatment is simply removing the trigger.

A transmural, skip-lesion inflammation that can strike anywhere from mouth to anus, so fistulae, strictures and patchy malabsorption are the predictable consequences of depth and distribution rather than separate diseases.

A failure of the lower oesophageal sphincter barrier lets acid reflux into an oesophagus not built to tolerate it, so the symptom pattern follows directly from where and how often that acid tracks backwards.

A disorder of gut-brain signalling and visceral hypersensitivity with no structural lesion at all, so the diagnosis is made positively from a symptom pattern rather than by exclusion, once red flags are absent.

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.

An ulcer forms wherever acid and pepsin overwhelm the mucosa's protective defences, so the site, the trigger and the danger of bleeding all fall out of that single imbalance.

A continuous, mucosa-limited inflammation that always starts at the rectum and spreads proximally, so bloody diarrhoea, colonic-only disease and the risk of toxic megacolon all follow from that single anatomical rule.

Blood loss from a lesion proximal to the ligament of Treitz is a time-critical circulatory emergency before it is a diagnostic puzzle, so resuscitation and risk-stratification always precede finding the source.