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Definition
Kidney cysts are round pouches of fluid that form in the kidneys. Kidney cysts can be associated with serious disorders that can impair kidney function. But more commonly, kidney cysts are a type called simple kidney cysts — noncancerous cysts that rarely cause complications.
It's not clear what causes simple kidney cysts. Simple kidney cysts typically occur as one cyst on the surface of a kidney. But simple kidney cysts can occur as multiple cysts affecting one or both kidneys.
Simple kidney cysts are often detected during an imaging test being done for another condition. Simple kidney cysts that don't cause signs or symptoms usually don't require treatment.
Symptoms
Simple kidney cysts typically don't cause signs or symptoms. If a simple kidney cyst grows large enough, kidney cyst symptoms may include:
- Dull pain in your back or side
- Fever
- Upper abdominal pain
When to see a doctor
Make an appointment with your doctor if you have signs or symptoms that worry you.
Causes
It's not clear what causes simple kidney cysts.
Risk factors
The risk of simple kidney cysts increases as you get older, though they can occur at any age.
Complications
Kidney cysts can occasionally cause complications, including:
- An infected cyst. A kidney cyst may become infected, causing fever and pain.
- A burst cyst. A kidney cyst that bursts causes severe pain in your back or side.
Preparing for your appointment
If a simple kidney cyst was discovered during an imaging test for another disease or condition, you may be worried about what it means for your health. At your next appointment, be prepared with a list of questions for your doctor. Discussing simple kidney cysts with your doctor may help put your mind at ease and help you feel more in control of your condition.
Here are some questions that might help facilitate a discussion with your doctor:
- What is the size of my kidney cyst?
- Is my kidney cyst new or has it been visible on other scans?
- Is my kidney cyst likely to grow?
- Can my kidney cyst hurt my kidney?
- I have these unexplained symptoms. Could they be caused by a kidney cyst?
- Does my kidney cyst need to be removed?
- What are my treatment options?
- What are the potential risks of each treatment option?
- Should I be alert for signs or symptoms that indicate my kidney cyst is growing?
- Should I see a specialist?
- Are there any restrictions that I need to follow?
- Are there any brochures or other printed material that I can take with me? What websites do you recommend?
- What will determine whether I should plan for a follow-up visit?
Tests and diagnosis
Tests and procedures used to diagnose simple kidney cysts include:
- Imaging tests. Imaging tests, such as ultrasound, computerized tomography (CT) and magnetic resonance imaging (MRI), are often used to investigate simple kidney cysts. Imaging tests can help your doctor determine whether a kidney mass is a cyst or a tumor.
- Kidney function tests. Testing a sample of your blood may reveal whether a kidney cyst is impairing your kidney function.
Treatments and drugs
Treatment may not be necessary
If your simple kidney cyst causes no signs or symptoms and doesn't interfere with your kidney function, you may not require treatment. Instead, your doctor may recommend that you undergo an imaging test, such as ultrasound, periodically to see whether your kidney cyst has enlarged. If your kidney cyst changes and causes signs and symptoms, you may opt to have treatment at that time. Sometimes a simple kidney cyst goes away on its own.
Treatments for kidney cysts that cause signs and symptoms
If your simple kidney cyst is causing signs and symptoms, your doctor may recommend treatment. Options may include:
- Puncturing the cyst and filling it with alcohol. To shrink the cyst, your doctor inserts a long, thin needle through your skin and through the wall of the kidney cyst. Then the fluid is drained from the cyst. Next, the cyst is often filled with an alcohol solution to prevent it from reforming. The cyst may return, so this procedure is reserved for certain situations.
- Surgery to remove the cyst. A large cyst may require surgery to drain and remove it. To access the cyst, the surgeon makes several small incisions in your skin and inserts special tools and a small video camera. While watching a video monitor in the operating room, the surgeon guides the tools to the kidney and uses them to drain the fluid from the cyst. Then the walls of the cyst are cut or burned away.
Last Updated: 2010-05-15
