Kidney cysts: Symptoms, Risk factors, Complications, Diagnosis, Treatment and Outlook

Updated: September 28, 2019

The round fluid filled sacs that are formed in the kidneys are called as Kidney cysts. Simple kidney cysts do not cause complications or affect kidney function in any way. However, they may cause pain, become infected, or cause other symptoms if they grow too large.
Simple kidney cysts are different from the cysts that form due to polycystic kidney disease. Polycystic kidney disease is a genetic condition that may cause numerous cysts, enlarge the kidneys, and affect kidney function. The kidneys develop cysts as a result of long term damage from kidney disease or dialysis in case of acquired cystic kidney disease. It is different from polycystic kidney disease because it is not genetic but happens as a result of other kidney problems. Treating the underlying cause can cure acquired cystic kidney disease. The kidneys are two bean-shaped organs located behind the abdominal organs and just under the rib cage whose main function is to  filter out the waste from the blood before it is passed out of the body as urine. They are also vital in regulating blood pressure and managing many other important functions in the body.

Symptoms of Kidney cysts:

Most simple kidney cysts are asymptomatic in its early stage and they do not cause any symptoms. However, if a kidney cyst grows large enough, it may cause noticeable symptoms.
These symptoms can include:

• dull pain in the back or side
• pain in the upper abdomen or hips
• fever if the cyst becomes infected
• need to urinate frequently
• blood in the urine

If a complication occurs, such as an infection or a rupture, symptoms may intensify.

Risk factors of Kidney cysts:

The most common factor for developing simple kidney cysts is aging. Adults over age 40 are at higher risk of developing it. Diet and lifestyle factors do not seem to impact the risk of developing these cysts. Men may be slightly more likely to develop simple kidney cysts than women. Kidney cysts may be caused by existing kidney diseases, or long-term treatment by dialysis in some cases.

Complications of Kidney cysts:

Complications of simple kidney cysts include:

• ruptured cysts
• infected cysts
• swollen kidneys caused by urine obstruction

Symptoms may intensify when these complications occur and the person require immediate medical attention. Most complications, including ruptured cysts, can be managed. However, they can be life threatening if left untreated.

Diagnosis of Kidney cysts:

As simple kidney cysts do not cause any symptoms, mostly these are discovered during imaging tests done for other reasons
Other diagnostic tests may be done to find out more about the growth once a kidney cyst is found. These tests can include:

• CT scans: Computerized imaging that creates a three dimensional picture of the kidneys to show tumors or cysts.
• MRIs: MRI stands for magnetic resonance imaging is a technique where the MRI scaner uses magnetic and radio waves to create pictures of tissues, organs and other structures within the body, which can then be viewed on a computer. MRI scanning is painless and there is no exposure to X-rays or any other damaging forms of radiation.
• Ultrasounds: Imaging that uses sound waves to create a picture of the kidneys.
• Kidney function test: A simple blood test that checks how well the kidneys are working.
• Urinalysis: A procedure that measures the contents of urine from a urine sample.

All these test be performed on an outpatient basis. Most of the time, no preparation is needed before these test. However, a person should always follow the instructions of a doctor prior to undergoing these test.

Treatment of Kidney cysts:

Most simple kidney cysts require only periodic monitoring until they starts growing. Kidney cysts that grow larger and cause symptoms may require treatment, particularly if they block the flow of urine or blood through the kidneys. In these cases, draining the cyst, using a procedure called sclerotherapy will be recommended.
An ultrasound to guide a needle to the cyst will be used during sclerotherapy. The sac of fluid is then punctured with the needle and drained. A saline solution will be will injected into the area to harden the surrounding tissue and prevent another cyst from forming. The procedure is done using local anesthesia and on an outpatient basis. Surgery may be required to drain or remove the growth in case of a very large cyst which is very rare. The surgeon makes several small incisions in your skin and inserts special tools and a small video camera to access the cyst. The surgeon guides the tools to the kidney watching a video monitor in the operating room and uses the tool to drain the fluid from the cyst. Then the walls of the cyst are cut or burned away. Antibiotic can be started prior to any other treatment in case of an infected cyst.

Outlook of Kidney cysts:

Simple kidney cysts are normally harmless and do not require any treatment. Treatment is required when there is a blood or a urine blockage within the kidney.