HSP Nephritis Diagnosis and Management

Clinical Presentation and Diagnosis

The American Academy of Pediatrics suggests that renal involvement occurs in approximately 20-50% of children with HSP and represents expected disease progression rather than a separate diagnosis 1, 2, 3
The presence of palpable purpura, renal involvement (hematuria and/or proteinuria), arthralgia/arthritis (bilateral ankle swelling), and abdominal pain are diagnostic criteria for HSP nephritis 4
The triad of hematuria, purpuric lesions, and ankle pain is specifically diagnostic of HSP 4

Urinalysis with microscopy is essential to assess severity of glomerulonephritis, looking for red blood cell casts and dysmorphic RBCs (indicate glomerular involvement) 4
Quantify proteinuria to assess renal function 1, 2, 3
Basic metabolic panel including BUN, creatinine, and complete blood count to assess renal function 4
Blood pressure measurement is essential as hypertension indicates more severe renal involvement 4
Renal biopsy should be performed if there is decreased renal function at presentation, severe nephrotic syndrome (proteinuria >3.5 g/day) or nephritic syndrome, or deteriorating kidney function 1, 2, 3

For persistent proteinuria 0.5-1 g/day per 1.73 m², start ACE inhibitor or ARB therapy, targeting proteinuria to <1 g/day/1.73 m² 1, 2, 3, 4, 5
For persistent proteinuria >1 g/day per 1.73 m² after ACE-I/ARB trial and GFR >50 ml/min per 1.73 m², consider 6-month course of corticosteroid therapy 1, 2, 3, 4, 5
For crescentic HSP with nephrotic syndrome and/or deteriorating kidney function, treat with high-dose intravenous methylprednisolone plus cyclophosphamide 1, 2, 3, 4, 5, 6

Do NOT use corticosteroids prophylactically at HSP onset to prevent nephritis—moderate quality evidence (Level 1B) shows no benefit 1, 2, 3, 4, 6
Do NOT delay imaging or assume isolated hematuria requires no evaluation if an abdominal mass is palpable, as this could represent a separate pathology like Wilms tumor 7
Do NOT use NSAIDs (like ketorolac/Toradol) for pain control in HSP patients with renal involvement, as they can cause acute kidney injury, use acetaminophen as first-line analgesic instead 4