Which condition may be asymptomatic but is associated with recurrent nephrolithiasis and sterile pyuria?

Which condition may be asymptomatic but is associated with recurrent nephrolithiasis and sterile pyuria?

• A. Medullary sponge kidney
• B. Polycystic kidney disease
• C. Renal cell carcinoma
• D. Acute pyelonephritis

Answer: (A)

Medullary sponge kidney is a congenital dilation of the collecting ducts in the renal medulla, creating cystic spaces within the papillae. This abnormal ductal pattern leads to urine stasis and mineral precipitation, so calcium-containing stones form more readily and recur over time. The chronic dilation and irritation of the papillary tissue can produce white blood cells in the urine without an actual bacterial infection, which is what sterile pyuria describes. Many people with this condition have no symptoms, and stones or microscopic hematuria may be the first clue. Imaging often shows dilated collecting ducts in the medulla with medullary calcifications, and IV contrast studies may reveal a characteristic appearance of the papillae. While other renal diseases can feature stones or flank pain, medullary sponge kidney uniquely combines medullary ductal dilation with recurrent nephrolithiasis and sterile pyuria, frequently in an asymptomatic individual.

Medullary sponge kidney is a congenital dilation of the collecting ducts in the renal medulla, creating cystic spaces within the papillae. This abnormal ductal pattern leads to urine stasis and mineral precipitation, so calcium-containing stones form more readily and recur over time. The chronic dilation and irritation of the papillary tissue can produce white blood cells in the urine without an actual bacterial infection, which is what sterile pyuria describes. Many people with this condition have no symptoms, and stones or microscopic hematuria may be the first clue. Imaging often shows dilated collecting ducts in the medulla with medullary calcifications, and IV contrast studies may reveal a characteristic appearance of the papillae. While other renal diseases can feature stones or flank pain, medullary sponge kidney uniquely combines medullary ductal dilation with recurrent nephrolithiasis and sterile pyuria, frequently in an asymptomatic individual.