Polycystic Kidney Disease (PKD)
Polycystic kidney disease (PKD) is a genetic disease that causes multiple small cysts, or fluid-filled sacs, to develop in the kidneys. Most cases cause no problems until the age of 30 to 50 years old, when they have grown large enough to affect the functioning of the kidneys, causing symptoms or changes to blood tests. This is so-called adult PKD, as although children are born with it, symptoms don't appear until adulthood.
It’s also known as autosomal dominant PKD (ADPKD – the most common type) according to how it is inherited. Each parent has a 1 in 2 chance of passing it on to their child. ADPKD affects around 1 in 800 people in the UK, with men and women being equally affected.
More rarely, symptoms may be seen in babies or children, and this is called infantile PKD or autosomal recessive PKD. It’s more serious as the kidneys are under strain from an early age and cysts can also appear on the liver. It’s inherited only if both parents carry the faulty gene.
Around a quarter of PKD cases have no known family history, it either occurs spontaneously or was never diagnosed in relatives. They can pass the condition on to their children.
Doctor’s advice
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How do I know if I have polycystic kidney disease?
If you have a parent with PKD you can have an ultrasound scan to check your kidneys and this can sometimes happen early such as with a pregnancy scan. Symptoms that the kidneys are enlarged or under strain include pain in the lower back or sides, recurrent urinary tract infections (UTIs, kidney stones, blood in the urine or high blood pressure.
A scan showed a cyst on my kidney, what does this mean?
You may have a scan of your kidney for any reason – such as an acute kidney injury (AKI or recurrent UTIs – and this may show a cyst on the kidney. Depending on its size and location, most times, this is relatively harmless and simply a consequence of getting older if your kidney function tests are normal and you have no symptoms. In these cases you might be monitored every so often to check the cyst has not substantially grown or to see if it has spontaneously disappeared.
How is polycystic kidney disease monitored?
You will have regular blood tests – at least once a year – to monitor how well your kidneys are functioning. If they show persistent deterioration – such as if the creatinine level is repeatedly raised or increases – you will be diagnosed with chronic kidney disease (CKD, which is permanent damage to the kidneys.
You will have regular ultrasound scans to check the size of the kidneys as thousands of cysts cause it to enlarge. If there are any abnormalities, other scans may be organised to consider if there are any blockages in the tubes carry urine from the kidneys to the bladder and out of the body.
How is polycystic kidney disease treated?
Unfortunately there is no treatment for PKD. As with any case of CKD, you should look after the things you can look after, so:
- lose weight if you are overweight or obese
- stop smoking if you are a smoker
- follow a diet low in fat, sugar and salt and take regular exercise
- If you do develop diabetes, high blood pressure or high cholesterol, you should engage in treatment for this and follow your doctor’s advice to keep this well-controlled
PKD can sometimes progress from the early stages of CKD to advanced CKD, or end-stage renal failure, which requires dialysis or a kidney transplant and autosomal recessive CKD carries a higher risk of this. A medication called tolvaptan may be considered in adults with rapidly progressive PKD, but this is given under specialist guidance. About half of people with ADPKD have developed end-stage kidney disease by the age of 60, with about 6 in 10 developing it by the age of 70 or above.
PKD carries a higher risk of other life-threatening conditions, including heart attacks and stroke and problems with blood vessels in the brain, such as bleeding (subarachnoid haemorrhage) or bulging (brain aneurysm).
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