Kidney Cyst - Causes, Symptoms, Diagnosis, and Treatment

What Is a Kidney Cyst?

A fluid-filled round pouch that grows inside a kidney is called a cyst. Kidneys are bean-shaped organs that produce urine by clearing out waste from the bloodstream. Single or multiple cysts can be present in a single kidney or both kidneys. Kidney cysts do not usually produce any symptoms and are harmless. As they do not produce any signs or symptoms, they are mostly diagnosed accidentally during an abdominal scan for some other condition. Sometimes, kidney cysts are associated with severe conditions, which can disrupt kidney function. If the size of the kidney cyst is small, it can be managed without surgery, but if it is large, it needs to be treated through surgery.

What Are the Types of Kidney Cysts?

The two types of kidney cysts are:

Simple Kidney Cysts: These are usually noncancerous and rarely cause any complications. The cause still needs to be clarified, though. Often, a single cyst is seen on the surface of the affected kidney. These cysts do not cause any symptoms and do not require treatment. These cysts can be removed without surgery.

Polycystic Kidney Disease: Polycystic kidney disease is a condition where multiple cysts form on the kidneys. This type of cyst damages the kidney function and structure as they grow larger.

What Is Meant by a Larger Kidney Cyst?

Renal cysts are small cysts filled with fluid and are round or oval. They do not cause any symptoms and can be diagnosed only through image testing. When these cysts are unusually larger, they are called larger kidney cysts. These larger kidney cyst causes pain and block the way urine is. This cyst needs to be treated by inserting a needle into the cyst and draining the contents of the cyst. These cysts usually require surgery.

What Is Polycystic Kidney Disease (PKD)?

It is an inherited condition resulting in cluster cysts within the kidneys. It makes the kidneys enlarge and causes loss of kidney function over time. These cysts can vary in size and shape and grow very large. The cyst can also grow in the liver or other body organs. Polycystic kidney disease can result in high blood pressure and kidney failure. The incidence of complications can be reduced with the help of lifestyle changes and treatments. Most complications are preventable and depend on the severity of the condition.

What Causes a Kidney Cyst?

The exact cause of kidney cysts is not known. The kidney has several tiny tubules that collect urine. It is believed that the following are the possible causes of kidney cysts:

• A cyst might start when these tubules get blocked, swell up, or get filled with push.

• When the weakened areas of the tubules form pouches (diverticula), they get filled with fluid and can result in a cyst.

What Are the Risk Factors Associated With Kidney Cysts?

The following are the factors that increase the risk of kidney cysts:

• People older than 50 years. Almost 50 percent of people older than 50 years have a kidney cyst.

• Polycystic kidney disease is an inherited disorder. So, it runs in families and results from changes to genes.

What Are the Symptoms of a Kidney Cyst?

Most of the cysts are very small, which cannot be seen with the naked eye and need a microscope. But, some cysts can grow big, compress nearby organs, and cause symptoms. Symptoms are also seen when the cyst becomes infected. Some of the symptoms of a simple kidney cyst, when it grows too big or gets infected, are:

• Fever.

• Dull back pain or between the ribs and pelvis.

• The pain becomes severe if the cyst bursts.

• Upper abdominal pain.

• Abdominal swelling.

• Frequent urination.

• Blood in the urine.

• Dark-colored urine.

The symptoms of polycystic kidney disease are:

• Back and side pain.

• Increased blood pressure.

• Blood in the urine.

How Is a Kidney Cyst Diagnosed?

Kidney cysts can be diagnosed by recording the patient’s history and determining the signs and symptoms. Suppose a person is suffering from any symptoms. In that case, the doctor will perform the following tests and procedures to diagnose kidney cysts and rule out other conditions that result in similar symptoms:

• Ultrasound, MRI (magnetic resonance imaging), or CT (computerized tomography) scan. These imaging tests are done to determine if the growth on the kidney is a cyst or a tumor.

• Kidney function tests to check if the growth is impairing the functioning of the kidneys.

• Urinalysis is a method in which the content of the urine is tested.

How Is a Kidney Cyst Treated?

Some asymptomatic cases, which are cysts that cause no signs or symptoms or do not interfere with kidney function, do not usually need treatment. For such cysts, the doctor will suggest getting periodic imaging tests (ultrasound) to check if the kidney cyst is growing. The doctor will recommend treatment if the kidney cyst increases in size or starts producing symptoms. Sometimes, a simple kidney cyst resolves on its own.

The treatment for symptomatic kidney cysts includes:

• Sclerotherapy- In this case, kidney cyst removal is done without surgery. The cyst is punctured and drained and then filled with alcohol. The doctor will first inject an anesthetic solution and then insert a long and thin needle into the cyst wall through the skin with the help of an ultrasound. Then, the needle is used to draw out the fluid. The cyst is refilled with alcohol to prevent a recurrence.

• Surgery- If the cyst is big and affects kidney function, then the cyst needs to be surgically removed. The cyst is first drained and then removed. The surgeon makes several small cuts in the skin and inserts specialized instruments through the incisions. The instruments have a camera at their end, which helps the surgeon visualize and guide the instruments to drain the fluid filled in the cyst. The pouch surrounding the cyst is then burned or cut off.

What Are the Possible Complications of a Kidney Cyst?

In rare cases, simple kidney cysts can result in the following possible complications:

• The cyst can rupture and cause pain.

• Back pain.

• The cyst can get infected.

• The kidneys get swollen due to urine obstruction.

• High blood pressure.

• Blood in the urine.

What Size of Kidney Cyst Is Dangerous?

When the cyst is small, it can be removed without surgery. When the cyst is larger than three centimeters, it can interrupt the flow of urine. In some cases, the size of the cyst can cause blood in the urine. In these cases, the kidney cyst is considered to be dangerous. These need to be treated immediately. When not treated, it can cause pain in the sides, stomach, and back, fever, frequent urination, and blood.

Conclusion:

A kidney cyst is usually harmless and does not cause any complications. When the size of the kidney cyst is small, it can be managed without surgery. Surgery or sclerotherapy can help prevent permanent kidney damage if the cyst grows. If a person is experiencing these symptoms, immediate medical advice should be sought. When treated promptly, most complications are not fatal. But if left untreated, the symptoms may worsen and can also be fatal.