A 32-year-old man presents with a 3-day history of painless hematuria and acute kidney injury (creatinine 3.8 mg/dL). He reports a recent upper respiratory infection. Urinalysis shows dysmorphic RBCs and RBC casts. Ultrasound shows normal kidney size. Serum complements are normal. Renal biopsy shows mesangial IgA deposits on immunofluorescence. What is the diagnosis?

• A IgA nephropathy (Berger disease) ✓
• B IgA vasculitis (Henoch-Schonlein purpura)
• C Lupus nephritis Class II
• D Post-infectious glomerulonephritis

Explanation

IgA nephropathy presents with synpharyngitic hematuria (gross hematuria concurrent with or within 1-3 days of URI), mesangial IgA deposits on biopsy, and normal complements. IgA vasculitis is identical pathologically but occurs in children and is associated with palpable purpura, arthralgia, and abdominal pain. This adult without extrarenal features has IgA nephropathy. PIGN follows streptococcal infection with low C3 and subepithelial humps. Lupus nephritis shows full-house immunofluorescence.

Reference: Brenner and Rector's The Kidney, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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