What is the treatment approach for a pediatric or adolescent patient with nephritic syndrome, considering the underlying cause and severity of the condition?

Treatment of Nephritic Syndrome

Critical Distinction: Nephritic vs. Nephrotic Syndrome

Nephritic syndrome requires a fundamentally different treatment approach than nephrotic syndrome, focusing on the underlying glomerulonephritis rather than proteinuria management. The evidence provided primarily addresses nephrotic syndrome, but nephritic syndrome is characterized by hematuria, hypertension, acute kidney injury, and inflammatory glomerular disease rather than the edema and massive proteinuria seen in nephrotic syndrome 1.

Immediate Assessment and Diagnosis

Urgent referral to a nephrologist (within 2 weeks) is mandatory for any patient presenting with nephritic syndrome to establish the specific glomerular disease through renal biopsy. 2

Key Clinical Features to Identify:

• Hematuria with red blood cell casts (distinguishes nephritic from nephrotic) 1
• Hypertension (often acute onset) 1
• Acute kidney injury with rising creatinine 1
• Fluid retention (but less severe edema than nephrotic syndrome) 1
• Proteinuria (present but typically sub-nephrotic range) 1

Essential Diagnostic Workup:

• Quantitative proteinuria measurement (PCR or ACR) to distinguish from nephrotic range 2
• Serologic testing for infection-related GN, IgA nephropathy, lupus nephritis, ANCA-associated vasculitis, and membranoproliferative GN 1
• Renal biopsy to establish the specific glomerular disease and guide treatment 2, 1

Disease-Specific Treatment Approaches

Infection-Related Glomerulonephritis:

Treat the underlying infection with specific antimicrobial agents as the primary intervention. 3 Most cases resolve with infection treatment alone, though supportive care for hypertension and fluid overload is necessary 1.

IgA Nephropathy:

Optimal blood pressure control and antiproteinuric therapy with ACE inhibitors or ARBs must be initiated before considering immunosuppression. 3 For patients with persistent proteinuria >1 g/day despite optimal supportive care, corticosteroids may be considered 3.

Lupus Nephritis:

Immunosuppressive therapy is required and should be guided by biopsy class. Treatment typically involves corticosteroids combined with either mycophenolate mofetil or cyclophosphamide 1.

ANCA-Associated Vasculitis:

Aggressive immunosuppression with corticosteroids plus cyclophosphamide or rituximab is essential to prevent irreversible kidney damage. 1 This represents a medical emergency requiring immediate nephrology consultation.

Membranoproliferative Glomerulonephritis:

Treatment depends on the underlying etiology (complement-mediated vs. immune complex-mediated), requiring specialized testing and nephrology expertise 3, 1.

Supportive Management

Blood Pressure Control:

Aggressive antihypertensive therapy is mandatory to prevent further kidney damage and cardiovascular complications. 4 ACE inhibitors or ARBs should be first-line agents when not contraindicated 3.

Fluid Management:

Loop diuretics should be used to manage fluid overload and hypertension. 4 If oral diuretics are ineffective, intravenous administration with addition of hydrochlorothiazide may be necessary 4.

Monitoring for Complications:

• Acute kidney injury progression requires close creatinine monitoring 1
• Infection risk is elevated, particularly with immunosuppressive therapy 1
• Cardiovascular complications from acute hypertension 1

Pediatric Considerations

In children with Henoch-Schönlein purpura (HSP) nephritis presenting with acute nephritic syndrome, randomized controlled trials comparing 6-12 months of steroid therapy to shorter duration are needed, but current practice favors corticosteroid treatment for moderate to severe disease. 3

For children with more severe HSP nephritis (acute nephritic syndrome with decreased GFR and >50% crescents), calcineurin inhibitors or mycophenolate mofetil may be considered, though evidence is limited. 3

Critical Pitfalls to Avoid

• Do not delay nephrology referral while attempting to complete diagnostic workup in primary care 2, 1
• Do not confuse nephritic with nephrotic syndrome as treatment approaches differ fundamentally 1
• Do not start immunosuppression without biopsy confirmation of the specific glomerular disease (except in life-threatening ANCA vasculitis where treatment may precede biopsy) 2
• Do not use albumin infusions as these are indicated for nephrotic syndrome, not nephritic syndrome 3
• Do not withhold treatment for ANCA-associated vasculitis while waiting for biopsy results, as delay causes irreversible damage 1