Medullary sponge kidney, also known as Cacchi-Ricci disease, is a birth defect where changes occur in the tubules, or tiny tubes, inside a fetus’ kidneys.
In a normal kidney, urine flows through these tubules as the kidney is being formed during a fetus’ growth. In medullary sponge kidney, tiny, fluid-filled sacs called cysts form in the tubules within the medulla—the inner part of the kidney—creating a spongelike appearance. The cysts keep urine from flowing freely through the tubules. As it collects in the cysts all calcium is combined and turned in to a kidney stone and as it grows it will at some point dislodge from that spot and will make its way down the kidney and to the mouth of the ureter to then be passed with your bathroom brea or may need surgery if it’s 5mm or larger as most people with msk are not able to pass any stone larger then 5mm depending on your body
Symptoms of medullary sponge kidney do not usually appear until the teenage years or the 20s. Medullary sponge kidney can affect one or both kidneys.