What is the recommended first‑line and subsequent management for a school‑age child with idiopathic nephrotic syndrome presenting with edema, heavy proteinuria, hypoalbuminemia and hyperlipidemia?

Management of Childhood Idiopathic Nephrotic Syndrome

Start with oral prednisone 60 mg/m²/day (maximum 60 mg) given once each morning for 4–6 weeks, followed by prednisone 40 mg/m² on alternate days for an additional 4–6 weeks. 1

Initial Diagnostic Approach

For a school-age child presenting with edema, heavy proteinuria, hypoalbuminemia, and hyperlipidemia, you should presume idiopathic nephrotic syndrome and initiate corticosteroid therapy without kidney biopsy if the child is between ages 1–10 years and lacks red-flag features. 1, 2

When to Perform Kidney Biopsy

Do NOT biopsy typical presentations in children aged 1–10 years who respond to steroids. 1

DO biopsy immediately if any of these red flags are present:

• Age < 1 year or > 12 years 1
• Macroscopic hematuria 1, 2
• Hypertension 1, 2
• Low C3 complement levels 1, 2
• Persistent renal failure 1, 2
• Steroid resistance after 8 weeks of therapy 1

First-Line Corticosteroid Therapy

Standard Regimen

Prednisone 60 mg/m²/day (maximum 60 mg/day) given as a single morning dose for 4–6 weeks, then switch to prednisone 40 mg/m² on alternate days for 4–6 weeks. 1

Choosing Between 8-Week vs 12-Week Protocol

Use the 8-week regimen (4 weeks daily + 4 weeks alternate-day) for:

• Children achieving rapid remission within 7 days 1
• Children at high risk for steroid complications (obesity, diabetes, psychiatric illness) 1

Use the 12-week regimen (6 weeks daily + 6 weeks alternate-day) for:

• Typical presentations to potentially lower relapse risk 1
• Do not extend beyond 12 weeks—no additional benefit is demonstrated 1

Definition of Remission

Remission is achieved when urine dipstick shows trace or negative protein for at least three consecutive days. 1

Management of Relapse (Steroid-Sensitive Disease)

When relapse occurs (urine dipstick ≥ 3+ protein for three consecutive days after prior remission):

• Restart prednisone 60 mg/m²/day until remission is achieved (≥ 3 consecutive days trace/negative) 1
• Then switch to prednisone 40 mg/m² on alternate days for 4 weeks 1

When to Initiate Steroid-Sparing Therapy

Start steroid-sparing agents when the child experiences:

• ≥ 2 relapses within 6 months (frequently relapsing nephrotic syndrome) 1, 3
• Relapse during steroid taper or within 14 days of stopping steroids (steroid-dependent nephrotic syndrome) 1, 3

Critical Timing Rule

Always achieve remission with prednisone FIRST before starting any steroid-sparing agent. 1, 3 Starting these agents during active relapse is a common and serious error.

First-Line Steroid-Sparing Agent

Levamisole is the recommended first-line steroid-sparing agent due to its efficacy, safety profile, and low cost. 1, 3

Levamisole Protocol

• Dose: 2.5 mg/kg on alternate days (maximum 150 mg per dose) 1, 3
• Duration: Minimum 12 months 1, 3
• Concurrent therapy: Continue low-dose alternate-day prednisone on the days without levamisole 3
• Monitoring: CBC every 2–3 months to detect neutropenia; liver enzymes every 3–6 months 3

Levamisole Adverse Effects

Discontinue immediately if:

• Neutropenia or agranulocytosis develops 3
• Skin rash appears 3
• ANCA becomes positive 3

Never restart levamisole after severe neutropenia. 3

Alternative Steroid-Sparing Options

If Levamisole is Unavailable or Ineffective

Oral cyclophosphamide:

• 2 mg/kg/day for 12 weeks (cumulative maximum 168 mg/kg) 1, 3
• Must achieve remission with steroids first 3
• Weekly CBC to monitor for leukopenia 3
• NEVER give a second course due to irreversible gonadal toxicity 1, 3

Calcineurin inhibitors:

• Cyclosporine 4–5 mg/kg/day (target trough 60–150 ng/mL) OR 1, 3
• Tacrolimus 0.1 mg/kg/day (target trough 5–10 ng/mL) 1, 3
• Continue for ≥ 12 months if remission is achieved 1, 3
• Monitor serum creatinine regularly for nephrotoxicity 1, 3
• Consider kidney biopsy if renal function declines 3

Second-line agents (if above fail):

• Mycophenolate mofetil 1200 mg/m²/day divided twice daily 1, 3
• Rituximab 375 mg/m² IV for 1–4 doses 1, 3
• Screen for hepatitis B and latent TB before rituximab 3

Management of Steroid-Resistant Nephrotic Syndrome

Steroid resistance is defined as failure to achieve remission after 8 weeks of corticosteroid therapy. 1

Mandatory Steps

Perform kidney biopsy immediately after confirming 8 weeks of steroid failure (unless genetic/familial cause already identified). 1, 4

Initiate genetic testing within 2 weeks because monogenic SRNS does not respond to immunosuppression. 1

First-Line Treatment for SRNS

Calcineurin inhibitors (cyclosporine or tacrolimus) are first-line therapy for steroid-resistant disease:

• Continue for minimum 6 months 1
• If partial or complete remission is achieved by 6 months, extend therapy to 12–24 months 1
• If no response by 6 months, discontinue and switch to alternative therapy 1

Second-Line Options for SRNS

If CNI fails after 6 months:

• Mycophenolate mofetil 1200 mg/m²/day divided twice daily 1
• Rituximab 375 mg/m² IV for 1–4 doses 1

If genetic testing confirms monogenic SRNS, discontinue all immunosuppressive therapy as it will not be effective. 1

Supportive Care & Monitoring

Daily Home Monitoring

• Daily urine dipstick testing by caregivers to detect early relapse 1
• Daily weight and blood pressure measurements during active disease 1

Laboratory Monitoring During Active Treatment

• Weekly serum albumin and creatinine while on initial steroid therapy 1
• Spot urine protein-to-creatinine ratio to quantify proteinuria response 1

Edema Management

For mild edema: No specific diuretic therapy needed; improves with steroid-induced diuresis. 5

For moderate to severe edema:

• Fluid restriction to insensible losses plus urine output during severe edema/oliguria 1, 5
• Furosemide after correcting hypovolemia 1, 5
• IV albumin 0.5–1 g/kg before diuretic in markedly hypoalbuminemic patients 1, 5

Infection Prevention

Pneumococcal vaccination is recommended due to heightened infection risk from both disease and immunosuppression. 1

Critical Pitfalls to Avoid

Do not start steroid-sparing agents during active relapse—always achieve remission with prednisone first. 1, 3

Complete the full 8–12 week initial steroid course even if remission occurs early; premature discontinuation increases relapse risk. 1

Do not perform kidney biopsy in typical presentations (age 1–10 years, no red-flag features, steroid-responsive). 1

Never repeat cyclophosphamide due to irreversible gonadal toxicity. 1, 3

Maintain minimum 12-month duration for steroid-sparing agents; shorter courses are associated with higher relapse rates. 1, 3

Monitor for levamisole-induced neutropenia with CBC every 2–3 months and discontinue if neutropenia develops. 3

Do not delay kidney biopsy beyond 8 weeks of documented steroid resistance. 1, 4

Assess CNI nephrotoxicity regularly with serum creatinine; consider biopsy if renal function declines. 1, 3