PassFinals
Renal & Urology

Nephrotic syndrome

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.

In a nutshell

Nephrotic syndrome is heavy urinary protein loss with hypoalbuminaemia and oedema. The same protein leak causes hyperlipidaemia, thrombosis and infection risk. Confirm the pattern, look for AKI or nephritic overlap, involve nephrology, treat oedema cautiously, reduce proteinuria when safe and use cause-specific therapy rather than automatic immunosuppression.

Classic presentation

A child or adult develops periorbital or dependent pitting oedema, frothy urine, weight gain, heavy proteinuria and low serum albumin.

Key points

  • The core pattern is heavy proteinuria, hypoalbuminaemia and oedema; hyperlipidaemia is common but not required for recognition.
  • Oedema can coexist with effective intravascular depletion, so aggressive diuresis can cause AKI.
  • Thrombosis, infection and renal decline are urgent complications; ask about pulmonary embolism, renal-vein thrombosis and serious infection.
  • Marked haematuria, red-cell casts, severe hypertension or rapidly falling renal function suggests nephritic or rapidly progressive overlap.
  • New adult nephrotic syndrome needs nephrology-led cause assessment and often biopsy; typical childhood disease may follow a paediatric steroid pathway without immediate biopsy.
  • ACE inhibitor or ARB therapy may reduce proteinuria when blood pressure, renal function and potassium allow, but is unsafe to start or continue blindly during hypovolaemia or AKI.
  • Thromboprophylaxis is individualised using thrombotic and bleeding risk; it is not automatic for every patient.
  • Treatment of the underlying cause, vaccination and safety-netting are as important as oedema control.

First-line investigation

Urine protein quantification and sediment, serum albumin, creatinine/eGFR, electrolytes, blood pressure and a cause-directed secondary screen, with renal biopsy considered by nephrology.

Management

Assess complications and involve nephrology

  • Arrange renal assessment for new nephrotic syndrome and emergency review for pulmonary oedema, suspected thrombosis, serious infection, shock, oliguria, AKI, rapidly progressive renal decline or severe hypertension.1,2,4

Confirm the pattern and cause

  • Quantify urine protein, examine sediment, check albumin, creatinine/eGFR, electrolytes and blood pressure, and arrange cause-directed screening; involve nephrology about biopsy, especially in adults.1,2

Treat oedema and proteinuria safely

  • Use dietary sodium restriction and cautious loop-diuretic treatment, monitoring perfusion, weight, urine output, renal function and electrolytes; consider ACE inhibitor or ARB for proteinuria only when haemodynamically and biochemically safe.1,3,4,6

Treat the underlying glomerular disease

  • Use a paediatric or adult nephrology pathway for disease-specific treatment; do not assume that every nephrotic presentation needs the same steroid or immunosuppressive regimen.1,2,6

Prevent thrombosis and infection

  • Investigate suspected thromboembolism urgently and individualise prophylactic anticoagulation after balancing thrombotic and bleeding risk; review vaccines and treat suspected infection promptly, especially during immunosuppression.1,5,3,6

Monitor relapse, kidney function and treatment harm

  • Follow oedema, weight, blood pressure, urine protein, albumin, creatinine/eGFR, potassium, infection, thrombosis and medicine toxicity, with explicit safety-netting for breathlessness, fever, pain, swelling or oliguria.2,1,3

Exam traps

  • Do not equate visible oedema with intravascular overload: check perfusion, blood pressure, urine output and renal function.
  • Do not give routine empiric steroids to an undifferentiated adult with nephrotic syndrome without renal advice.
  • Do not anticoagulate automatically: weigh albumin, cause, thrombosis risk, bleeding risk, kidney function and biopsy plans.
  • Heavy proteinuria with prominent haematuria, hypertension or a rapidly rising creatinine is not uncomplicated nephrotic syndrome.
  • A child with a typical steroid-sensitive presentation and an adult with new nephrotic syndrome do not follow the same biopsy pathway.
  • Fever, abdominal pain, chest pain, breathlessness, unilateral swelling or oliguria needs urgent assessment.

Illustrations

The glomerular filtration barrier and podocyte injuryDiagram comparing intact endothelial, basement-membrane and podocyte filtration layers with podocyte foot-process effacement and albumin leakage in nephrotic syndrome.PassFinals · original
Why nephrotic syndrome causes oedemaMechanism diagram linking urinary albumin loss to hypoalbuminaemia, reduced oncotic pressure, interstitial oedema and compensatory sodium and water retention, while warning that effective circulating volume may still be low.CharlesPicavet, Wikimedia Commons · Public domain
Nephrotic complications and renal assessmentClinical pathway linking heavy proteinuria to oedema, thrombosis, infection, AKI and CKD, with investigation and escalation points for renal-vein thrombosis, pulmonary embolism and hypovolaemia.Kristoffer Lindskov Hansen, Michael Bachmann Nielsen and Caroline Ewer, Wikimedia Commons · CC-BY-4.0

Key sources

  1. UK Kidney Association: Commentary on the KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases (UK renal commentary on the disease-specific KDIGO glomerular-disease pathway, used because no dedicated current NICE nephrotic-syndrome guideline was identified; published April 2023 and listed by UKKA when accessed.)
  2. NICE NG203: Chronic kidney disease—assessment and management (Current NICE principles for proteinuria and albuminuria, defining and investigating CKD, renal function monitoring and identifying treatable glomerular disease.)
  3. Kidney Care UK: Nephrotic syndrome in adults, updated June 2025 (Current UK patient and clinician-facing information on oedema, thrombosis, infection, lipid management, vaccination, sodium and fluid measures and specialist treatment.)
  4. NICE NG148: Acute kidney injury—prevention, detection and management (NICE principles for recognising and managing AKI risk during hypovolaemia, diuresis, infection and acute renal decline.)
  5. UK Renal Pharmacy Group/UK Kidney Association: Updated vaccine guidance for kidney patients, autumn 2025 (UK vaccination update covering people with nephrotic syndrome, CKD and immunosuppression in relation to the current national schedule.)
  6. BNF online: current prescribing information for diuretics, renin-angiotensin system medicines, corticosteroids and anticoagulants (Use the current BNF and local renal protocols for dose, renal adjustment, contraindications, monitoring and interactions; fixed dosing is not reproduced here.)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.