14884 Kidney Cysts

Overview

A simple kidney cyst is a round, fluid-filled sac that can form on or inside a kidney. It is usually harmless and does not affect how well your kidney works.

Yes, simple kidney cysts are very common, especially in people over 50. They are often found by accident, so many people are unaware they have one.

Simple kidney cysts most often affect adults over 50, and they are slightly more common in men than in women. They are rare in children.

Symptoms

Common symptoms

• No symptoms at all in most cases
• Dull ache or pain in the side or back
• A feeling of fullness or heaviness in the belly
• Blood in the urine
• Needing to urinate more often or pain when urinating if there is an infection

Symptoms in children

• Simple kidney cysts are uncommon in children, and most cause no symptoms.
• If symptoms do occur, they are the same as in adults, such as side or belly discomfort.
• A child found to have a kidney cyst will usually be referred to a kidney specialist for a full check.

Symptoms in older adults

• Kidney cysts are more common in older adults and are often found by chance.
• They rarely cause symptoms, even when present.
• If symptoms appear, they are usually a mild ache in the side or back that can be mistaken for age-related stiffness.

Causes

Main causes

• The exact cause is not fully understood.
• A simple kidney cyst is thought to form when the surface layer of the kidney weakens and makes a fluid-filled pouch.
• This is a normal part of ageing and is not caused by your diet or lifestyle.

Risk factors

• Being over 50 years old
• Being male
• Having a family history of simple kidney cysts (in some cases, but this is not always the case)

When to see a doctor

See a doctor urgently if:

• If you have sudden severe pain in your side or back
• If you see blood in your urine
• If you have fever and back or side pain

Book a routine appointment if:

• If you have a dull ache that does not go away
• If you notice changes in your urination
• If a cyst was found on a scan and you have questions or concerns

Diagnosis

Most simple kidney cysts are found when you have an ultrasound, CT, or MRI scan for another reason. Your doctor can usually tell that a cyst is simple and harmless from the scan images.

Tests that may be done

• Ultrasound scan – uses sound waves to make pictures of the kidneys
• CT or MRI scan – more detailed scans if the ultrasound is not clear enough
• Blood and urine tests – to check kidney function and to look for signs of infection or blood

What to expect at your appointment

If your cyst is simple and you have no symptoms, you may not need any further tests or treatment. Your doctor may just ask you to report any new symptoms. If the cyst looks unusual, you may be referred to a kidney specialist for more tests.

Treatment

Treatment is only needed if a cyst is causing pain, blocking urine flow, or becomes infected. Most simple kidney cysts do not need treatment at all.

Self-care at home

• Drink plenty of fluids unless your doctor advises otherwise
• Use simple pain relief for mild aches – ask your pharmacist or doctor what is safe for you
• Keep your regular doctor appointments so any changes are noticed early

Medical treatments

For cysts that cause symptoms, a specialist can drain the fluid with a thin needle, or use a procedure to shrink the cyst. If there is an infection, you may be given antibiotics to treat it. These treatments are only considered when necessary and are usually quick.

When is surgery considered?

Surgery is rarely needed. If a cyst is very large, keeps causing problems, or treatments have not helped, a surgeon may remove it using keyhole surgery. This is not common.

Living with this condition

For most people, a simple kidney cyst does not change day-to-day life. You can continue your normal work, exercise, and hobbies. If you have symptoms, talk to your doctor about ways to manage them.

Lifestyle tips

• Stay active and keep a healthy weight
• Avoid smoking and limit alcohol to protect your kidneys
• Tell your doctor about any new or worsening symptoms

Diet and exercise

There is no special diet for simple kidney cysts. Eat a balanced diet with plenty of vegetables, fruit, and whole grains, and drink enough fluids. If you have other kidney problems, follow the diet advice from your healthcare team.

Mental health and emotional wellbeing

Finding out you have a kidney cyst can be worrying, but it is important to remember that most are harmless. If it is causing you stress or affecting your sleep, speak to your doctor. You can also ask about counselling or support services.

Prevention

No, simple kidney cysts cannot be prevented. They are part of normal ageing. Living a healthy lifestyle is good for your kidneys, but it will not stop cysts from forming.

Complications

If left untreated

• Most simple kidney cysts do not cause complications and can be left alone safely.
• Rarely, a cyst can become infected, which may cause fever and pain.
• A very large cyst might press on the kidney or nearby organs, but this is uncommon and can be treated.

Long-term outlook

The outlook for simple kidney cysts is very good. They are not cancer and do not usually affect kidney function. If a cyst does cause symptoms, treatment is safe, simple, and effective in most cases.

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