Medullary sponge kidney

Medullary sponge kidney (MSK), also known as Cacchi-Ricci disease or precalyceal canalicular ectasia, is a congenital malformation of the kidneys characterized by dilation (ectasia) of the collecting tubules in the renal medulla, giving the kidney a sponge-like appearance on imaging. The dilated tubules can be found in one or both kidneys and may affect one or several renal papillae. The condition primarily affects the urinary system and is often discovered incidentally during imaging studies performed for other reasons. Many individuals with medullary sponge kidney remain asymptomatic throughout their lives. However, the dilated collecting ducts predispose to urinary stasis, which can lead to recurrent kidney stones (nephrolithiasis), recurrent urinary tract infections, and hematuria (blood in the urine). Kidney stones, typically composed of calcium oxalate or calcium phosphate, are the most common clinical manifestation and may cause renal colic (flank pain). Some patients also develop nephrocalcinosis (calcium deposits within the kidney tissue). A defect in urinary acidification and hypercalciuria (excess calcium in the urine) are frequently observed metabolic abnormalities. Renal function is generally preserved, though complications from recurrent stones or infections can occasionally lead to impaired kidney function over time. There is no cure for medullary sponge kidney, and treatment is directed at managing symptoms and preventing complications. Management strategies include adequate hydration to reduce stone formation, dietary modifications, and thiazide diuretics or potassium citrate to address hypercalciuria and urinary acidification defects. Urinary tract infections are treated with appropriate antibiotics. Kidney stones may require intervention such as extracorporeal shock wave lithotripsy or ureteroscopy if they cause obstruction or significant symptoms. Regular follow-up with a nephrologist or urologist is recommended to monitor kidney function and manage recurrent stone disease.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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