What is Medullary Cystic Kidney Disease

What is medullary cystic kidney disease? Cystic kidney disease is a common kind of kidney disorder which is characterized by single or multiple fluid-filled sacs in renal tissues. Medullary indicates the location of the cysts is in the renal medullary areas. The kidney consists of renal pelvis and renal parenchyma which is made up of renal cortex and renal medulla. Renal medulla is made up of 15-20 renal pyramids.

Renal cystic disease was considered to be a rear disease, however it has become very common in recent years with the development of diagnostic method. Even very small cysts can be found, for example B ultrasound can detect small cyst of 0.5-1cm and CT scan can detect even smaller ones of 0.3-0.5cm.

There are two types of medullary cystic diseases---medullary sponge kidney and Juvenile nephronophthisis medullary cystic disease complex. Here we will mainly focus on medullary sponge kidney. The lesions of medullary sponge kidney are mainly in renal pyramids. Its pahtogenesis is not clear at present and it might be the formation of spongy-shaped cavities due to cystic dilation of the collecting tubes. The diameters of these cysts are often less than 0.7cm and they are filled with opaque jelly and often there is small stone or calcium deposition.

Though patients have medullary sponge kidney since their birth, they have no symptoms and the urine test and kidney function are all normal. It is often found due to its complications such as kidney stone and renal infections. The disease is often found when patients have sudden renal colic, blood in urine, urinary irritation, pyuria and further tests are done. If the cystic lesions are extensive, the functions of urine concentration and acidification will be affected and the excretion of calcium in urine will increase.

The prognosis is good and there are very few cases will develop renal failure. As for treatments for medullary cystic diseases, there is at present no special treatments. Rectifying electrolyte imbalances especially hyponatremia and low blood volume can improve kidney functions and slow down its progression into renal failure.

If there is urinary tract infections, anti-fungal treatments will be offered.

If there is kidney stone, patients should drink more water to maintain daily urine volume of above 2000ml.