Makindo Medical Notes

Related Subjects: | Metabolic Acidosis | Lactic Acidosis | Acute Kidney Injury (AKI) | Renal Physiology | Chronic Kidney Disease (CKD) | Anaemia in CKD | Analgesic Nephropathy | Medullary Sponge Kidney | IgA Nephropathy (Berger's Disease) | HIV-associated Nephropathy (HIVAN) | Balkan Endemic Nephropathy (BEN) | Autosomal Dominant Polycystic Kidney Disease

📖 Exam Information: Patients with nephrotic syndrome have an increased risk of venous thrombosis (loss of antithrombin III in urine). ⚠️ Despite dramatic oedema, patients may be intravascularly volume-depleted → important when managing fluids and diuretics.

🩺 About Nephrotic Syndrome

• 💧 Proteinuria >3–4.5 g/day.
• ⬇️ Hypoalbuminaemia (<30 g/L).
• 🌊 Oedema/anasarca – often facial swelling in the morning.
• 📈 Hyperlipidaemia (cholesterol often >10 mmol/L).

🔍 Additional Key Findings

• 🩸 Thrombophilia: Loss of antithrombin III → ↑ risk of DVT, renal vein thrombosis, and PE.
• 🦠 Infection Risk: Loss of IgG in urine predisposes to sepsis, cellulitis, peritonitis (e.g., pneumococcus).
• ⚡ Renal Vein Thrombosis: Classic triad = flank pain + haematuria + acute kidney injury.

📊 Primary Causes

• 👶 Minimal Change Disease – most common in children.
• 🧩 Focal Segmental Glomerulosclerosis (FSGS) – associated with HIV, heroin, obesity.
• 🧬 Membranous Nephropathy – common in adults; associated with HBV, SLE, malignancy.

🌍 Secondary Causes

• 💉 Diabetes Mellitus
• 💛 Amyloidosis
• 🦴 Multiple Myeloma
• 🤰 Preeclampsia
• 💊 Drugs: Gold, Penicillamine, NSAIDs, Captopril
• 🦠 Infections: HBV, malaria, leprosy, SLE
• 🎗️ Malignancies: lymphoma, carcinoma, CLL

🧑‍⚕️ Clinical Presentation

• 👀 Periorbital oedema – worse in mornings.
• 🌊 Generalised oedema (anasarca).
• 🫧 Frothy urine (proteinuria).
• 📉 Fatigue, malaise, weight gain from fluid overload.

🔎 Investigations

• 🧪 Serum albumin ⬇️ (<30 g/L).
• 🚰 Urine protein >3 g/L (protein:creatinine ratio useful).
• 🩸 Lipids: raised cholesterol and triglycerides.
• FBC & clotting, CRP/ESR.
• Immunology: ANA, dsDNA, ANCA, complements (C3/C4).
• Urine Bence Jones proteins (myeloma).
• 🩻 Imaging: CXR for malignancy; renal ultrasound.
• 📍 Renal biopsy – essential for diagnosis in adults.

💊 Management Principles

• 🔎 Identify cause → biopsy in adults unless clearly diabetic nephropathy.
• 🥗 Salt restriction + fluid balance monitoring.
• 💊 Diuretics: loop, thiazide, or metolazone (with caution – avoid over-diuresis in hypovolaemia).
• 🧪 Anticoagulation: LMWH/warfarin for DVT prophylaxis if high risk.
• ⚖️ Monitor weight & BP daily.
• 📉 Statins may be used for severe hyperlipidaemia (though evidence limited).

🎯 Cause-Specific Therapy

• 👶 Minimal Change: Corticosteroids first line; cyclophosphamide if resistant.
• 🧬 Membranous Nephropathy: ACEi/ARB, ± steroids, cytotoxics, rituximab.
• 🦠 Lupus Nephritis: Steroids + cyclophosphamide/mycophenolate.
• 💉 Diabetic Nephropathy: Tight glucose + BP control (ACEi/ARB).
• 🎗️ Amyloidosis: Treat underlying cause.
• 🧩 FSGS: Steroids ± calcineurin inhibitors.

⚠️ Complications

• 🩸 Venous thrombosis (esp. renal vein).
• 🦠 Infection (loss of IgG + oedema).
• 📈 Severe hyperlipidaemia → ↑ risk of atherosclerosis.
• 🫁 Pulmonary oedema in advanced disease.

📚 Case Examples

• 👶 Child with puffy eyes and frothy urine: Minimal Change Disease; responds rapidly to steroids.
• 🧑 40-year-old with proteinuria + HBV: Think Membranous Nephropathy.
• 👩 Middle-aged diabetic with proteinuria + retinopathy: Diabetic nephropathy most likely.
• 🧓 Elderly man with nephrotic syndrome + macroglossia: Consider Amyloidosis.

📌 Exam Pearls

• Nephrotic = Proteinuria + Hypoalbuminaemia + Oedema + Hyperlipidaemia.
• Nephritic = Haematuria + Hypertension + Oliguria + Mild proteinuria.
• Always check for underlying malignancy in older adults with nephrotic syndrome 🎗️.
• Renal vein thrombosis is a classic complication 💡 (loin pain, haematuria, sudden renal impairment).

Cases — Nephrotic Syndrome

• Case 1 — Minimal change disease (childhood) 🧒: A 6-year-old boy presents with periorbital swelling, frothy urine, and weight gain over 2 weeks. Urine dip: 4+ protein, no haematuria. Serum albumin 18 g/L, cholesterol elevated. Renal biopsy would likely show podocyte effacement on EM. Diagnosis: minimal change nephrotic syndrome. Managed with high-dose corticosteroids.
• Case 2 — Focal segmental glomerulosclerosis (adult) 🧍‍♂️: A 34-year-old man with long-standing hypertension develops ankle swelling and proteinuria. Bloods: albumin 22 g/L, creatinine mildly elevated. Renal biopsy: focal segmental sclerosis. Diagnosis: FSGS causing nephrotic syndrome. Managed with steroids, immunosuppression, and blood pressure control (ACE inhibitor).
• Case 3 — Secondary cause (diabetes) 🍬: A 59-year-old man with type 2 diabetes (20 years) presents with oedema, frothy urine, and declining renal function. Urine ACR: 500 mg/mmol. Fundoscopy: diabetic retinopathy. Diagnosis: diabetic nephropathy with nephrotic syndrome. Managed with glycaemic and BP control, ACE inhibitor, and nephrology referral.

Teaching Point 🩺: Nephrotic syndrome = proteinuria, hypoalbuminaemia, oedema, and hyperlipidaemia. Causes include minimal change (children), FSGS & membranous GN (adults), and secondary causes (diabetes, lupus, amyloid). Complications: thrombosis, infection, AKI.