Medullary Sponge Kidney (Cacchi-Ricci Disease)

What is medullary sponge kidney?

Medullary sponge kidney is a congenital disorder meaning you're born with it. This condition causes small, fluid-filled cysts to form in the medulla of your kidneys.

Your kidneys are part of your urinary system. The medulla is the middle part of each kidney. It contains tiny tubules that collect the urine waste your kidneys filter out of your blood. The tubules empty into collecting ducts, and those ducts empty into the center of your kidney (renal pelvis). Urine (pee) travels from your kidneys to your bladder through ureters and to the outside of your body through your urethra.

In medullary sponge kidney, the collecting ducts develop cysts and become dilated or enlarged. This causes the tissue to look spongelike.

Medullary sponge kidney usually affects both kidneys but it can also occur in only one.

How does medullary sponge kidney occur?

When cysts develop, they prevent the tubules from functioning properly. Calcium builds up inside the tubules in a process called nephrocalcinosis. Other substances like phosphate and oxalate can also build up. Eventually, these substances stick together and form kidney stones.

The cysts and stones can also prevent urine from flowing through the tubules. This can lead to urinary tract infections.

How does medullary sponge kidney differ from polycystic kidney disease?

Polycystic kidney disease is a condition that is usually inherited. It causes many cysts throughout your kidneys that lead to kidney enlargement.

Polycystic kidney disease can cause serious complications and disability. Many people with polycystic kidney disease develop kidney failure and need dialysis to filter their blood. Kidney failure is relatively rare in people with medullary sponge kidney.

Who does medullary sponge kidney affect?

This condition seems to occur randomly. Some cases may run in families, but researchers have not found a specific pattern of inheritance.

Most people don’t receive a diagnosis until they experience symptoms, usually in their 20s. Women and people designated female at birth are at a slightly higher risk than men or people designated male at birth.

How common is medullary sponge kidney?

About 1 in 5,000 people have medullary sponge kidney. In people who have kidney stones, it's much more common — between 12% and 20%.

Can medullary sponge kidney cause hypertension?

There is currently no evidence that medullary sponge kidney causes hypertension.

What causes medullary sponge kidney?

Healthcare providers are not sure why some people develop this condition. It likely occurs due to a problem with kidney formation during fetal development in utero.

What are the symptoms of medullary sponge kidney?

Many people have no signs of the disease. Only about 10% develop symptoms. These are usually associated with urinary tract infections and kidney stones and may include:

• Blood in your urine (hematuria).
• Flank pain on either side of your back just under your rib cage.
• Painful urination (dysuria).
• Kidney stones.
• Urinary tract infections.

How is medullary sponge kidney diagnosed?

Your provider will perform a physical exam. This includes a review of your medical history, family history and symptoms.

If your provider suspects you have kidney disease, you will likely receive blood and urine tests to check for:

• Blood in your urine.
• Kidney function.
• Urinary tract infection.

Your provider may also order imaging tests to look for cysts. Common imaging tests include:

• CT scan, uses X-rays to create a 3D view of your kidneys.
• Intravenous pyelogram, involves a series of X-rays taken after injecting dye into one of your veins. Your kidneys filter the dye from your blood into your urine. The dyed urine shows up on the X-ray and helps your provider see cysts and areas of urine blockage.
• Ultrasound, uses sound waves to create a picture of your kidneys.

How is medullary sponge kidney treated?

There is no specific treatment for medullary sponge kidney. Treatment centers around managing urinary tract infections and kidney stones.

The main treatment for urinary tract infections is antibiotics.

Treatment for kidney stones depends mainly on stone size. Small stones usually pass on their own. To help move the stone along, your provider may recommend drinking more fluids. You may also receive pain medications or medications to relax your ureter muscles. Ureters carry urine from your kidneys to your bladder.

Larger stones usually require more treatment, such as:

• Shock wave lithotripsy: This is a noninvasive procedure that uses high-energy shock waves to break up kidney stones. The broken stone fragments then pass through your urine and out of your body.
• Ureteroscopy: A ureteroscopy uses a long, thin tube called a ureteroscope to reach the stones. This tool allows your provider to remove small stones or break up larger stones with a laser.
• Percutaneous nephrolithotomy: Providers use this procedure if less invasive methods are not successful. Percutaneous nephrolithotomy is a minimally invasive surgery that allows your provider to break up kidney stones and suction them out through a small incision in your back.

How can I prevent medullary sponge kidney?

Since medullary sponge kidney is a congenital condition with no known cause, you can't prevent it. But you can take steps to help prevent urinary tract infections and kidney stones.

Your provider may prescribe medications including:

• Low-dose antibiotics to prevent frequent urinary tract infections.
• Potassium citrate or thiazide (water pill) to reduce calcium levels in the urine and help prevent kidney stones.

Changing what you eat and drink can also help prevent urinary tract infections and kidney stones:

• Calcium: Getting the right amount of calcium in your diet can reduce kidney stone development.
• Fluids: Increasing fluids dilutes urine and helps prevent kidney stone formation. It also helps flush bacteria out of your kidneys.
• High protein foods: Limiting high protein foods such as meat, eggs and fish can help you avoid kidney stones.
• Salt: Cutting back on salt is important. Too much salt in your diet may increase your risk of developing kidney stones.

Talk to your provider or dietitian before making any changes to your diet.

What is the outlook for medullary sponge kidney?

Most people with this condition will maintain kidney function throughout their lives. About 10% of people develop kidney failure, most likely due to frequent, recurring UTIs or kidney stones.

Chronic pain is another rare complication for people who have frequent kidney stones. Strategies to prevent kidney stones can help this condition.

Medullary sponge kidney can also cause low levels of calcium in the blood, which can lead to weak bones. This increases the risk of developing bone health conditions, such as:

• Osteoporosis.
• Secondary hyperparathyroidism.

Your provider may prescribe medications such as potassium citrate to prevent long-term bone loss.

How can I live with medullary sponge kidney?

Your healthcare provider will track your kidney function and provide supportive care. Take your medications, follow dietary instructions and attend follow-up appointments. This can help prevent urinary tract infections and kidney stones.

A note from Cleveland Clinic

There is no cure for medullary sponge kidney. Most people with the condition never develop symptoms or know they have it. When symptoms do occur, they usually include urinary tract infections or kidney stones. Both are highly treatable. You can also prevent urinary tract infections and kidney stones with medications and dietary changes. Talk with your provider if you have any questions or concerns.