An 8-year-old boy presents with haematuria, oliguria, periorbital oedema, and blood pressure of 148/96 mmHg. Serum complement C3 is markedly low; C4 is normal. Anti-streptolysin O (ASO) titre is 600 IU/mL. Renal biopsy shows 'lumpy bumpy' IgG and C3 deposits on immunofluorescence. The single most reliable marker of recovery in this condition is:

• A Resolution of haematuria within 6 months
• B Normalization of blood pressure within 2 weeks
• C Return of urine output within 72 hours
• D Normalization of serum C3 within 8 weeks ✓

Explanation

Post-streptococcal glomerulonephritis (PSGN) characteristically activates the alternative complement pathway, causing selective C3 consumption (low C3, normal C4). Serum C3 normalises within 6–8 weeks in 90% of PSGN cases; failure to normalise should prompt consideration of membranoproliferative GN (which also depresses C3 but persistently). Microscopic haematuria may persist for up to 2 years without indicating poor prognosis. Blood pressure normalisation is expected early but is not a marker of complete renal recovery.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.