Medullary sponge kidney

Medullary sponge kidney (MSK) is a birth defect of the tubules-tiny tubes inside the kidneys. In a normal kidney, urine flows through these tubules as it is being formed. In MSK, tiny sacs called cysts form in the medulla-the inner part of the kidney-creating a sponge-like appearance. The cysts keep urine from flowing freely through the tubules.
The name medullary sponge kidney is misleading because the affected kidney does not resemble a sponge. The names tubular ectasia and cystic dilatation of the collecting ducts have been suggested as alternatives; however, medullary sponge kidney is the most commonly used name for this disorder.
Complications associated with medullary sponge kidney include the following (see Presentation, Workup, Treatmen t, and Medication):
Renal stones
Urinary tract infection (UTI)
Hematuria
Distal renal tubular acidosis (RTA; type 1 RTA)
Renal insufficiency (rarely)
Causes
MSK is a birth defect featured with dilation of a collection duct. The dilation is caused by occlusion by uric acid during fetal life or results from tubular obstruction due to calcium oxalate calculi secondary to infantile hypercalciuria.
Prognosis
MSK is usually associated with a good prognosis. However, Renal Insufficiency can account for 10% cases among people with the disorder.
Renal Failure rarely occurs. But in rare cases, it may occur due to repeated pyelonephritis and or urinary tract infection. Therefore, controlling infection is very important to prevent kidney damage.