A 9-year-old boy develops painless gross hematuria the same day as an upper respiratory tract infection. Blood pressure is normal, serum C3 level is normal, and urine microscopy shows dysmorphic red cells. Serum IgA levels may be elevated. What is the most likely diagnosis?
- A Post streptococcal glomerulonephritis
- B Thin basement membrane disease
- C IgA nephropathy ✓
- D Membranoproliferative glomerulonephritis
Correct answer: C. IgA nephropathy
Explanation
IgA nephropathy causes gross hematuria within 1 to 2 days of a mucosal infection (synpharyngitic hematuria), unlike post streptococcal glomerulonephritis which appears after a latent period of 1 to 3 weeks. Complement B3 is characteristically normal in IgA nephropathy but low in post streptococcal and membranoproliferative glomerulonephritis. Thin basement membrane disease causes persistent asymptomatic hematuria without episodic post infective bouts.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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