An intravenous urogram of a 35-year-old woman with recurrent haematuria shows bilateral kidneys with striated contrast pooling in the papillary regions, producing a brush like appearance of the collecting ducts. What is the most likely diagnosis?

• A Medullary sponge kidney ✓
• B Papillary necrosis
• C Autosomal dominant polycystic kidney disease
• D Nephrocalcinosis secondary to hyperparathyroidism

Explanation

Medullary sponge kidney is characterised by congenital ectasia of the medullary and papillary collecting ducts. On IVU, contrast fills these dilated ducts producing the classic paintbrush or bouquet of flowers appearance, often with small calculi lodged within the ectatic ducts. Papillary necrosis produces cavities communicating with calyces rather than parallel striations, and polycystic disease shows mass effect on the pelvicalyceal system instead.

Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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