What management is recommended for a 7-year-old child with a history of Henoch-Schönlein purpura (HSP) and persistent trace proteinuria?

Management of Persistent Trace Proteinuria in a Child with History of Henoch-Schönlein Purpura

For a 7-year-old child with history of Henoch-Schönlein purpura (HSP) and persistent trace proteinuria who is otherwise well, an ACE inhibitor or ARB should be initiated as first-line therapy to prevent progression of renal disease. 1

Assessment of Proteinuria Severity

Before initiating treatment, it's important to properly quantify the proteinuria:

• Confirm persistent proteinuria with first morning urine samples to rule out orthostatic proteinuria 2
• Quantify using urine protein-to-creatinine ratio (PCR)
• Assess kidney function with serum creatinine and estimated GFR

Risk Stratification

The degree of proteinuria in HSP nephritis correlates with prognosis:

• Trace proteinuria (<0.5 g/day/1.73m²): Lower risk but requires monitoring
• Moderate proteinuria (0.5-1 g/day/1.73m²): Moderate risk
• Nephrotic proteinuria (>1 g/day/1.73m²): Higher risk 3

Treatment Algorithm

1. For trace proteinuria (<0.5 g/day/1.73m²):

   • Initiate ACE inhibitor or ARB therapy 1
   • Target blood pressure below the 90th percentile for age and gender 1
   • In children, target 24-hour mean arterial pressure at 50th percentile for age, sex, and height by ambulatory blood pressure monitoring 1

2. If proteinuria persists >0.5-1 g/day/1.73m² despite ACE inhibitor/ARB:

   • Uptitrate ACE inhibitor or ARB to maximally tolerated dose 1
   • Consider referral to pediatric nephrologist 2

3. If proteinuria >1 g/day/1.73m² persists despite ACE inhibitor/ARB for 3-6 months:

   • Consider adding a 6-month course of corticosteroid therapy (if GFR >50 ml/min/1.73m²) 1

Monitoring Protocol

• Regular urine testing for proteinuria and hematuria every 3 months for at least 6 months 4
• Blood pressure measurement at each visit 1
• Renal function tests (serum creatinine, eGFR) every 6 months
• If proteinuria worsens or kidney function deteriorates, consider renal biopsy 1

Important Considerations

• HSP nephritis can manifest months after the initial presentation
• Persistent proteinuria beyond 6 months increases risk of long-term renal sequelae
• Children with history of HSP should be monitored for at least 6 months after diagnosis, even if initially asymptomatic 4
• Proteinuria goal in children should be <200 mg/g (<20 mg/mmol) or <8 mg/m²/hour 1

Potential Pitfalls

1. Underestimating trace proteinuria: Even trace proteinuria in HSP can progress to significant renal disease if untreated
2. Inadequate follow-up: HSP nephritis can develop months after initial presentation
3. Overtreatment: Not all children with trace proteinuria require immunosuppressive therapy; ACE inhibitors/ARBs are first-line
4. Medication adherence: Counsel parents about the importance of consistent medication administration, even if the child appears well

By following this approach, you can effectively manage persistent trace proteinuria in this child with HSP history, potentially preventing progression to more severe renal disease.