Nephrotic Syndrome in Children

🧒 Nephrotic syndrome (children) happens when glomerular podocyte injury causes heavy protein loss in urine 🩸➡️💧. Loss of albumin lowers plasma oncotic pressure → fluid shifts into tissues → oedema 💧, while the “effective” circulating volume may fall (so children can be oedematous yet intravascularly dry). The liver responds by increasing lipoprotein synthesis → hyperlipidaemia 🧈, and loss of anticoagulant proteins (e.g., antithrombin) contributes to thrombosis risk 🩸.

✅ Definition (typical paediatric nephrotic syndrome)

• Generalised oedema 💧
• Nephrotic-range proteinuria: urine PCR >200 mg/mmol (or equivalent nephrotic-range measure) 🧪
• Hypoalbuminaemia: albumin <25 g/L ⬇️
• Hyperlipidaemia is common 🧈 (supportive, not required for diagnosis)

⚠️ Causes (childhood)

• Most children have idiopathic nephrotic syndrome (often Minimal Change Disease) ✅
• Secondary causes exist (e.g., infection, SLE/HSP, drugs, malignancy) but are less common
• Many glomerular diseases can present with nephrotic-range proteinuria (± nephritic features)

🧾 Clinical pattern categories

🤒 Symptoms & signs

• Oedema often starts periorbital 👁️ then becomes generalised (legs, ascites, scrotal/vulval)
• Weight gain ⚖️, lethargy, reduced urine output 🚱
• Frothy urine ☁️ (protein)
• Red flags: abdominal pain, fever, breathlessness, severe headache, reduced perfusion/cool peripheries 🚨

🔬 Investigations (first presentation)

• Urine: PCR (or ACR), dip (blood), culture if febrile; consider microscopy
• Bloods: U&E/creatinine, albumin, cholesterol, FBC, CRP; consider LFTs
• “Atypical feature” screen (specialist-led): complement (C3/C4), ANA, hepatitis/other infection tests as indicated

🧫 When to consider renal biopsy (specialist decision)

• Atypical features: persistent haematuria, sustained hypertension 📈, low complement, impaired renal function/AKI
• Age extremes (very young infants, older children) or systemic features suggesting secondary disease
• Failure to respond to steroids (possible SRNS)

🩺 General management (key safety points)

• Early senior/paediatric nephrology involvement 👩‍⚕️👨‍⚕️
• Salt restriction 🧂⬇️ (often the most effective non-drug step for oedema)
• Fluid: avoid blanket restriction; assess volume status carefully (oedema ≠ euvolaemia) 💧
• Diuretics 💊: consider only with careful assessment and specialist advice (risk of hypovolaemia/AKI)
• Albumin infusion 💉: for suspected hypovolaemia or severe/refractory oedema under specialist protocol (often with loop diuretic)
• Daily weight ⚖️ and oedema charting; consider marking oedema extent
• Avoid NSAIDs 🚫 (renal perfusion risk)

💊 Prednisolone for first presentation (common UK regimen)

• Prednisolone 60 mg/m²/day (max often 60–80 mg) for 4 weeks
• Then 40 mg/m² alternate days for 4 weeks
• Then taper (e.g., 5–10 mg/m² alternate days weekly over ~4 weeks) 📉
• Most children with SSNS achieve remission early in treatment ✅

📋 Example taper table (first presentation)

🧯 Relapse & escalation (headline)

• Relapses are common; management depends on frequency and steroid toxicity
• Frequent relapses / SDNS: steroid-sparing agents may be used (e.g., levamisole, cyclophosphamide, calcineurin inhibitors) via nephrology
• SRNS: specialist pathway + biopsy; consider RAAS blockade (ACEi/ARB) to reduce proteinuria in selected cases

⚠️ Complications to watch for

• Infection 🦠 (especially pneumococcal; also cellulitis, peritonitis)
• Hypovolaemia / shock 🚨 (tachycardia, cool peripheries, abdominal pain, oliguria)
• AKI 🩺 (often from hypovolaemia, sepsis, nephrotoxins)
• Thrombosis/VTE 🩸 (abdominal pain, haematuria, chest symptoms, limb swelling)

💉 Vaccines & infection prevention (UK practical)

• Ensure routine immunisations are up to date ✅
• Annual influenza vaccine recommended 🦠➡️💉
• Consider pneumococcal vaccination/boosters per local pathway 💉
• Check varicella status; significant exposure while immunosuppressed may require urgent advice
• Avoid live vaccines during high-dose systemic steroids and for a period after stopping (follow local guidance)