Simple Kidney Cysts

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What are simple kidney cysts?

Kidney cysts are benign sacs of fluid that develop inside the kidneys. They are not the same as cysts that form with polycystic kidney disease, which is a genetic condition. The cause of simple kidney cysts is not known, and they are more common in older people.

Simple kidney cysts may not cause symptoms. Occasionally, however, a kidney cyst can cause pain, infection or bleeding. In rare cases, simple kidney cysts can interfere with proper kidney function. It is also thought that simple kidney cysts can lead to high blood pressure.

Kidney cysts are usually discovered during computerized tomography (CT) scans or ultrasound imaging studies that are performed for other reasons. Magnetic resonance imaging (MRI) will also detect kidney cysts. Most of the time, simple kidney cysts do not require treatment. If they cause symptoms, however, you need to see your health care provider. Treatment for simple kidney cysts includes draining the cyst using a long needle, or surgical draining of the cyst.

Seek immediate medical care (call 911) for severe, sudden pain in your back, abdomen or sides, along with a high fever (higher than 101 degrees Fahrenheit).

Seek prompt medical care if you have bothersome symptoms of kidney cysts, such as pain, discomfort, or difficulty urinating.

What are the symptoms of simple kidney cysts?

In most cases, simple kidney cysts will not cause any symptoms. Many people, especially older people, have simple kidney cysts without knowing it. In more serious cases, however, simple kidney cysts can lead to symptoms, including pain, kidney problems, and infection of the kidneys.

Common symptoms of simple kidney cysts

You may experience simple kidney cyst symptoms daily or only occasionally. Any of these symptoms can be severe:

Symptoms that might indicate a serious condition

In some cases, simple kidney cysts are a serious condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms:

What causes simple kidney cysts?

The cause of simple kidney cysts is not known. They are not genetic in origin. Simple kidney cysts are more common as you get older and may simply be a normal effect of aging. They are also more common in men. The fluid-filled sacs that are classified as simple kidney cysts are different from the kidney cysts that occur with polycystic kidney disease.

What are the risk factors for simple kidney cysts?

A number of factors increase the risk of developing simple kidney cysts. Not all people with risk factors will get simple kidney cysts. Risk factors include:

How are simple kidney cysts treated?

Simple kidney cysts do not usually require treatment. If they cause symptoms, such as pain or kidney problems, treatment may be required. Treatment for simple kidney cysts involves draining the cyst, either surgically or with a long needle.

Drainage of simple kidney cysts

Kidney cysts can be drained with or without surgery. Some common techniques for draining a simple kidney cyst include:

  • Conventional surgery (may require a brief hospital stay)

  • Laparoscopic (minimally invasive) surgery to drain the cyst, followed by cauterization (burning) to seal the wound (usually a quick procedure)

  • Use of a long needle guided into the kidney to draw fluid out of the cyst. Ultrasound can be used to make sure the cyst is fully drained. In some cases, alcohol may be injected into the kidney cyst to keep additional cysts from forming.

What are the potential complications of simple kidney cysts?

Simple kidney cysts may be symptomless. In most cases, they will not lead to complications. If the cyst is large or symptomatic, however, it can damage the kidneys, and complications can be serious. You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of simple kidney cysts include:

  • Complications of treatment
  • Kidney scarring
  • Loss of kidney function
  • Pain
  • Return of kidney cysts
  • Urinary tract infection
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 20
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Simple kidney cysts. National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC).
  2. Kidney cysts.