Minimal Change Disease — SAQ

Stem

A candidate is asked to manage a classic presentation of Minimal Change Disease in an exam setting. Use precise definitions, scores, doses, and decision thresholds.

Core knowledge (model answer backbone)

Minimal change disease (MCD) is the leading cause of nephrotic syndrome in children and the prototype of steroid-responsive podocytopathy. It accounts for roughly 90 percent of childhood and 10-15 percent of adult nephrotic presentations, with selective albuminuria, normal light microscopy, no immune deposits on immunofluorescence, and diffuse foot process effacement on electron microscopy. High-dose corticosteroids induce remission in over 80 percent of cases, with cyclophosphamide, calcineurin inhibitors, mycophenolate, and rituximab reserved for frequent relapsers, steroid-dependent, and steroid-resistant disease.

Red flags

• Sudden onset anasarca with breathlessness — suggests pulmonary oedema or pleural effusion requiring urgent resuscitation.
• Oliguria + rising creatinine + persistent heavy proteinuria — consider acute tubular necrosis or transformation to FSGS.
• Calf swelling, pleuritic chest pain, haemoptysis, or new atrial fibrillation — renal vein thrombosis or pulmonary embolism.
• Fever + abdominal pain + cloudy peritoneal fluid — primary bacterial peritonitis (Spneumoniae, E coli).

High-yield structure examiners expect

Cover: Overview & Definition, Classification, Epidemiology & Risk Factors, Pathophysiology, Clinical Presentation, Differential Diagnosis.

Key doses / thresholds (from topic teaching)

• UPCR greater than 3.5 g/day", label: "Diagnostic threshold", hi
• Albumin below 30 g/L", label: "Hypoalbuminaemia", hint: "O
• ften below 20 g/L in MCD" },
• greater than 3.5 g/g (or 300+ mg/mmol) confirms nephrotic-
• greater than 3.5 g/day in adults; less rigorously required
• typically below 25 g/L, often below 20 g/L; oedema roughly p

Questions

a) Define the condition and give the most important classification or severity framework used in exams. (3 marks)

• Clear one-line definition matching standard teaching.
• Named classification / stages / types with discriminating features.
• One sentence on why classification changes management.

b) Outline pathophysiology in a mechanism chain that explains the main clinical features. (3 marks)

• Initiating insult → intermediate pathway → end-organ effect.
• Link at least two symptoms/signs to mechanism.
• Mention one complication pathway (e.g. shock, perforation, herniation, arrhythmia).

c) List discriminating clinical features and bedside assessment. (3 marks)

• Classic presentation plus one atypical group (elderly, pregnancy, child, immunocompromised).
• Named signs/manoeuvres if relevant.
• What must never be missed on exam/bedside (pregnancy test, airway, glucose, etc.).

d) Investigations with thresholds and one named score if applicable. (3 marks)

• First-line tests and what positive findings mean.
• Gold-standard or definitive investigation when needed.
• Score components reproduced exactly if a named score is standard for this topic.

e) Immediate resuscitation and definitive management with doses where standard. (3 marks)

• ABC / time-critical steps first.
• First-line drug(s) with agent + dose + route (or procedure steps).
• Escalation triggers (theatre, ICU, thrombolysis window, antidote, etc.).
• Disposition and safety-netting.

Marking tips

Full marks require specificity (numbers, names, doses) not generic "give antibiotics/fluids." Regional practice (ICMR / NICE / AHA) may be cited as alternative where relevant.