What are kidney cysts?
Kidney cysts are round pouches of fluid that form on or in the kidneys. Most often, kidney cysts are a type called simple kidney cysts. Simple kidney cysts aren’t cancer and rarely cause problems.
It is not clear what causes simple kidney cysts. And its normal to have 3 or more cysts in each kidney after the age of 30 years.
Simple kidney cysts are often found during an ultrasound (or CT or MRI) for another condition. Treatment usually is not needed unless simple cysts cause symptoms.
So tell me more about what are kidney cysts.
Symptoms
Simple kidney cysts usually don’t cause symptoms. But if a simple kidney cyst grows large enough, symptoms may include: dull pain in the back or side, or fever (if they get infected; this is unusual).
Causes
It’s not clear what causes simple kidney cysts. One theory suggests that kidney cysts develop when the surface layer of the kidney weakens and forms a pouch. The pouch then fills with fluid, detaches and develops into a cyst.
Risk factors
The risk of having simple kidney cysts increases as you get older. But they can occur at any age. Simple kidney cysts are more common in men.
Complications
Kidney cysts may sometimes lead to complications, including:
- Infection – a kidney cyst may become infected, causing fever and pain
- Bursting – A kidney cyst that bursts causes severe pain in the back or side. Sometimes a burst cyst may cause blood in the urine
- Blocked urine flow – a large kidney cyst can block the ureter, and therefore the flow of urine. This is called urinary obstruction and is very rare.
Other types of cysts
- Complex cysts. Complex cysts need to be monitored with regular imaging (e.g. ultrasound) for changes that could be cancer
- Acquired kidney disease. This occurs as a complication of chronic kidney disease (CKD), if you have CKD4-5 for more than 5 years. People with acquired cystic kidney disease are more likely than people in the general population to have kidney cancer. However, the chance of that cancer spreading is lower in people with acquired cystic kidney disease
- Polycystic kidney disease (PKD)
- Medullary sponge kidney (MSK).
Summary
We have described what are kidney cysts. We hope it has been helpful.
Other resource
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Last Reviewed on 20 April 2024