A 30-year-old woman from West Africa has sickle cell trait (HbAS). She is incidentally found to have hematuria. Which complication of sickle cell trait explains this finding?

• A Membranoproliferative glomerulonephritis from immune complex deposition
• B Papillary necrosis of the renal medulla due to sickling in the hypertonic medullary vasculature ✓
• C Renal vein thrombosis secondary to hypercoagulable state
• D IgA nephropathy triggered by sickle cell-induced endothelial injury

Explanation

In sickle cell trait (HbAS), the low-oxygen, hyperosmolar, acidic environment of the renal medulla favors HbS polymerization even with only ~40% HbS, causing local sickling in vasa recta. This leads to renal medullary ischemia, papillary necrosis, and hematuria — the most clinically recognized renal complication of trait. Papillary necrosis can cause gross hematuria and is associated with analgesic nephropathy, diabetes, and sickle cell trait/disease. MPGN and renal vein thrombosis are not specifically associated with sickle cell trait.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.