Makindo Medical Notes

Related Subjects: |Metabolic acidosis |Lactic acidosis |Acute Kidney Injury (AKI) / Acute Renal Failure |Renal/Kidney Physiology |Chronic Kidney Disease (CKD) |Anaemia in Chronic Kidney Disease |Analgesic Nephropathy |Medullary Sponge kidney |IgA Nephropathy (Berger's disease) |HIV associated nephropathy (HIVAN) |Balkan endemic nephropathy (BEN) |Autosomal Dominant Polycystic kidney disease

🧾 Key Point: Minimal Change Disease (MCD) is the commonest cause of nephrotic syndrome in children. ✅ Prognosis is excellent – only ~1% progress to end-stage renal failure.

About 👶

• MCD = most common cause of nephrotic syndrome in children, especially boys under 5 years.
• Can occur in adults, but far less common.
• Strong steroid responsiveness ➝ good long-term outcome.

Causes & Triggers ⚡

• 🔹 Idiopathic in most cases (~80–90%).
• 🔹 Secondary causes (10–20%):
• 💊 Drugs: NSAIDs, rifampicin.
• 🦠 Infections: EBV (infectious mononucleosis).
• 🎗 Malignancies: Hodgkin’s lymphoma, NHL, thymoma.

Aetiology & Pathophysiology 🔬

• 👁 Electron microscopy: shows fusion/effacement of podocyte foot processes.
• ⚡ Loss of the negative charge of the GBM ➝ selective albuminuria.
• 📌 Associations: atopy, HLA-DR7, Hodgkin’s disease, NSAIDs.

Clinical Features 🤒

• 💧 Oedema: periorbital → peripheral → anasarca.
• 🍺 Frothy urine: due to heavy proteinuria.
• 🧪 Nephrotic syndrome triad: proteinuria, hypoalbuminaemia, hyperlipidaemia.
• ❌ Hypertension and haematuria are uncommon (contrast with other GN).

Investigations 🔍

• 🧪 U&E: usually normal.
• 💧 Urinalysis: highly selective proteinuria (>3 g/day, mainly albumin).
• 📉 Serum albumin: low (<25 g/L typical).
• ⬆️ Cholesterol/lipids: elevated.
• 🔬 Renal biopsy: not needed if classic presentation, but shows podocyte effacement on EM.

Management 🩺

• 💊 Steroids: Prednisolone 8 weeks then taper ➝ remission in ~90% children.
• 🔄 Relapses: occur in ~50% ➝ may require cyclophosphamide or ciclosporin.
• 💧 Supportive: fluid/salt restriction, diuretics for oedema, infection prophylaxis (pneumococcal vaccine >2yrs).

Prognosis 📈

• 🌟 Excellent with treatment – most achieve remission.
• ⚠️ Relapsing course common, but ESRF progression is very rare (~1%).
• 🦠 Infection (due to immunoglobulin loss) remains the main serious risk.

✨ Exam Pearl: Child with sudden oedema, frothy urine, hypoalbuminaemia + hyperlipidaemia = MCD until proven otherwise. 👉 If hypertension + haematuria present, think other causes (e.g., FSGS, membranous GN).

Cases — Minimal Change Disease (MCD)

• Case 1 — Childhood nephrotic syndrome 🧒: A 5-year-old boy presents with periorbital swelling, frothy urine, and ankle oedema. Urine dip: 4+ protein, no blood. Serum albumin: 16 g/L, cholesterol elevated. Renal function normal. Diagnosis: nephrotic syndrome due to minimal change disease. Managed with high-dose oral corticosteroids; biopsy often deferred unless atypical features develop.
• Case 2 — Relapsing disease in adolescence 🔄: A 14-year-old girl with a history of childhood nephrotic syndrome presents again with oedema after a viral URTI. Urine: heavy proteinuria. Previous biopsy: minimal change disease. Diagnosis: relapsing MCD. Managed with repeat steroid therapy, with consideration of calcineurin inhibitor if frequent relapses.
• Case 3 — Adult secondary MCD 💊: A 42-year-old man develops sudden-onset nephrotic syndrome while being treated with NSAIDs for chronic back pain. Renal biopsy: minimal change disease. Diagnosis: secondary MCD due to NSAID use. Managed by stopping NSAID, starting steroids, and nephrology follow-up.

Teaching Point 🩺: Minimal change disease is the commonest cause of nephrotic syndrome in children, but can also affect adults. It is usually steroid-responsive. Secondary forms may be triggered by NSAIDs, lymphoma, or infections. Electron microscopy shows podocyte foot process effacement.