People with ADPKD get cysts in their kidneys. Many get cysts in their liver too. These cysts are balls of tissue filled with fluid. Over the years, they grow in number and size. 

Sometimes, a single cyst or multiple cysts can get infected with microbes. These are cyst infections. 

Cyst infections are one of the more common problems that people with ADPKD face. About one in every 100 people with ADPKD get a cyst infection each year. They’re a common reason for having to stay in hospital. 

About 1 in every 10 hospital stays of people with ADPKD is for a cyst infection. 

An infection occurs when harmful microbes such as bacteria, fungi or viruses get into the body.  

Cyst infections are usually caused by bacteria from the gut. These bacteria sometimes find their way to a kidney or the liver. For example, they may travel up your urethra  (the tube you wee through) into your bladder and up to the kidneys.  

Bacteria might also enter your body during procedures or surgery.  

Escherichia coli (E. coli) is the most common cause of cyst infections. Other bacteria, such as Staphylococcus aureus, can also cause infections.  

You’re more likely to get cyst infections as you get older.  

Your risk is also increased if: 

• you’re a woman 

• you have a procedure or surgery on your kidneys or liver 

• you are receiving haemodialysis (a type of dialysis where a machine filters your blood) 

If you have an infected kidney cyst or liver cyst, you may: 

• have strong pain or tenderness in your abdomen (tummy), side or back 

• have a fever (a temperature of over 38°C)  

• feel cold or shivery 

• not feel hungry 

• feel generally unwell  

Some of these symptoms can be caused by other problems linked to ADPKD, such as a kidney stone, bleeding cyst, or bile duct infection.  

Fever and pain can also be signs of infection in other areas of your kidney or bladder. These are called urinary tract infections. We have a web page about them.  

If you have symptoms of a cyst infection and do not belong to any of the groups listed below, contact your GP during working hours or call NHS 111 at any time.  

Call 999 or go to A&E if any of the following apply to you: 

• You are pregnant 

• You have a weakened immune system (are immunosuppressed) or have had an organ transplant  

• You are receiving dialysis 

• You think you might have sepsis (see the signs of sepsis below) 

Signs of sepsis: 

• slurred speech or sudden confusion 

• extreme shivering or severe muscle pain  

• passing no urine (not peeing) in 24 hours  

• severe breathlessness  

• it feels like you might die 

• skin that is mottled, very pale, or blue  

See the following pages for advice on Sepsis The UK Sepsis Trust  

If your doctor (GP) thinks you might have a cyst infection, they’ll refer you to hospital for tests.  

These tests aim to: 

• check whether you have an infection or a different problem 

• find where the infection is 

• identify the bacteria causing it 

Tests include: 

• checking your temperature  

• checking for pain in your abdomen (tummy) and side  

• a urine test for bacteria  

• a blood test for bacteria and other signs of infection  

• imaging scans  

• taking a sample of fluid from the cyst 

Even with these tests, cyst infections can be hard to diagnose.  

In about half of cases, doctors can see the possible infected cyst on scan.  

In a small number of patients, doctors can take a sample of fluid from a cyst. They can only do this if the cyst can be reached safely using a needle. A laboratory can then check for bacteria in the sample. This helps to plan treatment. If your doctor can’t take a fluid sample but it’s likely you have a cyst infection, they can still treat it.  

Cyst infections are treated with antibiotics. If doctors can identify the bacteria causing your infection, this helps them to select an antibiotic that’s likely to work. If they can’t identify the bacteria, they’ll give you antibiotics that are likely to work. 

It takes a few weeks for some antibiotics to kill all the bacteria. This is because many antibiotics don’t travel into the cyst fluid well.  

You’ll probably need to take antibiotics for 4 to 6 weeks, but it could be a few months. 

Kidney cysts can usually be treated with antibiotic tablets. Less often, people need the medicine slowly put into a vein using a ‘drip’. These are called intravenous antibiotics.  

Liver cysts often need intravenous antibiotics at first. Most people can swap to antibiotic tablets once their infection is starting to get better.  

If your infected cyst is large, or antibiotics aren’t working, your doctor may suggest draining the fluid. They can usually do this with a long needle put through the skin. They will first numb the skin with local anaesthetic. 

Less often, people need surgery to drain or remove a cyst. 

After having your cyst drained you’ll need antibiotics to kill any bacteria left behind. 

See our web page Draining and treating cysts for more information.  

Sometimes, a cyst infection doesn’t clear up or soon returns. This can happen because not all the bacteria were killed off. Your doctor will suggest trying a different antibiotic. You might also need to have the cyst drained (see above) or removed by surgery. 

In rare cases where a person keeps getting bad cyst infections in a kidney, their kidney doctor might chat through the option of removing the kidney. Find out more on our web page on kidney removal (nephrectomy). 

If you keep getting liver cyst infections that are hard to treat, your liver doctor might recommend a liver transplant. Your treatment team will explain the pros and cons of a transplant and any other treatment options.

• Urinary tract infections 
• Pain 
• Kidney stones 
• Polycystic liver disease 
• Draining and treating cysts 
• Kidney removal (nephrectomy) 
• Kidney transplant 

The NHS website has information on CT scans, MRI scans and antibiotics.