Medullary Sponge Kidney (Cacchi-Ricci Disease)

Medullary sponge kidney (Cacchi-Ricci disease) is a condition that causes small, fluid-filled cysts to form in the medulla of your kidneys. It’s a congenital issue, meaning you’re born with it. This disorder doesn’t cause harm in most people who have it. But it leads to complications in some.

The medulla is the middle part of each kidney. It contains tiny tubules that collect the waste your kidneys filter out of your blood. Urine (pee) moves from the tubules into collecting ducts and on to your bladder before leaving your body. In medullary (pronounced “MED-el-er-ee”) sponge kidney, the tubules develop cysts and become dilated or enlarged. This causes the tissue to look spongelike.

This disease usually affects both kidneys (bilateral), but it can also occur in only one (unilateral).

About 1 in 5,000 people have medullary sponge kidney. It’s much more common in people who have kidney stones, affecting up to 2 in 10. Females are at a slightly higher risk than males.

Symptoms of medullary sponge kidney

Most people with medullary sponge kidney never develop symptoms or know they have it. Only about 1 out of 10 people with this condition have symptoms. These are usually from urinary tract infections (UTIs) and kidney stones, and may include:

• Blood in your pee (hematuria)
• Fever
• Flank pain on either side of your back, just under your rib cage
• Pain while peeing (dysuria)

A small number of people develop frequent kidney stones and long-term (chronic) pain.

Medullary sponge kidney causes

Experts aren’t sure what causes medullary sponge kidney. It likely happens due to a problem with how the kidneys form during fetal development.

This condition seems to occur randomly. But some affected individuals have a genetic variation. Medullary sponge kidney is associated with several conditions, like those that affect your connective tissue.

Complications

When cysts form, they keep your tubules from working properly. Calcium, phosphate and oxalate can build up inside the tubules. Over time, these substances stick together and form kidney stones.

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

Some people with medullary sponge kidney develop abnormalities in how their kidneys handle minerals, like calcium. Over time, this may contribute to bone loss and increase the risk of osteoporosis. Your provider may prescribe medicines to prevent long-term bone loss.

How doctors diagnose medullary sponge kidney

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

If your provider suspects you have kidney disease, you’ll likely receive blood and pee tests to:

• Check kidney function
• Look for issues like blood in your pee or a urinary tract infection

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

• CT scan, which uses X-rays to create a 3D view of your kidneys
• Ultrasound, which uses sound waves (from moving a wand over your belly) to create a picture of your kidneys

Most people don’t receive a medullary sponge kidney diagnosis until they have symptoms. This usually happens in their 20s.

How is it treated?

There’s no cure or specific treatment for medullary sponge kidney disease. Your healthcare provider will help you manage urinary tract infections and kidney stones.

The main way to treat and prevent UTIs is with antibiotics.

Treatment for kidney stones depends mainly on stone size. Most stones in people with this condition are small. They usually pass on their own. You may need to drink more fluids to help this happen. You may also receive medicine for pain or to relax muscles in the ureters the stone needs to pass through. Potassium citrate or thiazide may help prevent kidney stones.

Larger stones usually need more treatment, like:

• Shock wave lithotripsy: This uses shock waves outside your body to break up kidney stones so you pass the pieces in your pee.
• Ureteroscopy: A provider uses a long, thin tube to remove stones or break them up with a laser.
• Percutaneous nephrolithotomy: Providers use this minimally invasive surgery if less invasive methods don’t work. They break up kidney stones and suction them out through a small cut in your back.

When should I see a healthcare provider?

Contact a provider if you think you have a UTI or kidney stone. If you have a medullary sponge kidney diagnosis, you should have regular visits with an expert in the urinary system.

Questions to consider asking your provider may include:

• Do I need treatment?
• What kind of treatment do I need?
• How often do I need follow-up visits with you?
• What are my chances of developing other kidney problems?

What can I expect if I have medullary sponge kidney?

Medullary sponge kidney disease usually isn’t serious unless you have complications. Most people with this condition will have kidney function throughout their lives. Only about 1 out of 10 people with medullary sponge kidney develop kidney failure. This is most likely due to frequent UTIs and kidney stones.

Rarely, people with frequent kidney stones can have chronic pain.

Your healthcare provider will track your kidney function and provide supportive care. Take your medicines and go to your follow-up visits. This can help prevent UTIs and kidney stones.

Is there anything I can do to feel better?

Healthcare providers recommend drinking lots of water (2 liters or 67 ounces per day) if you have medullary sponge kidney disease. You should also include many fruits and vegetables in your meals. Limiting excess salt intake and avoiding very high-protein diets may help reduce the risk of kidney stones.