Overview
Polycystic kidney disease (PKD) is an inherited condition in which many fluid-filled sacs, called cysts, grow in the kidneys and make them larger. Over time the kidneys work less well. Cysts can also form in the liver.
There are two main types. Autosomal dominant PKD is the common type, often called adult PKD because it is usually diagnosed in adulthood. Autosomal recessive PKD is rare and usually shows in the first months of life, sometimes before birth. PKD progresses slowly and may eventually cause kidney failure.
Symptoms
The common adult form often causes no signs until the cysts have grown larger. Symptoms can include:
- Pain in the side, back or tummy
- Blood in the urine
- High , which often appears early
- Urine infections that keep coming back
- Kidney stones
When to see a doctor
See a doctor for blood in the urine, pain in the side or back that keeps returning, or urine infections that come back. If PKD runs in your family, ask about and genetic counselling, and have your checked even if you feel well.
Causes
PKD is caused by a change (mutation) in a gene, not by diet or lifestyle. In the dominant form the change is in the PKD1 or PKD2 gene, and one changed copy is enough. Most cases are passed on by an affected parent, and the rest begin as a new change.
The recessive form needs a changed PKHD1 gene from both parents, who are usually unaffected carriers.
Risk factors
- A parent with the dominant form of PKD, which is the main risk factor
- Both parents carrying a changed gene, for the rare recessive form
Complications
- High
- Kidney stones and urine infections
- Bleeding into a cyst, or a cyst that bursts
- Cysts in the liver, which can become infected
- Aneurysms: a bulge in a blood vessel in the brain or in the aorta, which can be life-threatening if it bursts
- Chronic kidney disease and kidney failure over time, which may need or a kidney transplant
Prevention
PKD is inherited, so it cannot be prevented, but the kidneys can be protected:
- Having your checked regularly and treated if it is high
- Eating less salt, as advised, within a healthy pattern such as the DASH plan
- Treating urine infections promptly
- Genetic counselling before planning children, if PKD runs in the family
Diagnosis
An scan of the kidneys is the usual first test and shows the cysts. A CT or may confirm the diagnosis and measure the kidneys. Blood and urine tests check how well they are working.
Genetic testing is used in some cases, for example when there is no family history or the picture is unclear. People with a family history of PKD who have headaches are checked for a brain aneurysm.
Treatment
There is no cure. The aim is to control symptoms, protect the kidneys and treat complications. PKD progresses slowly, and treatment can relieve symptoms for many years.
- Medicines to lower , often a type called ACE inhibitors or ARBs, and a low-salt diet
- , started promptly, for urine and cyst infections
- Pain relief as advised by the doctor. Cysts that are painful, infected, bleeding or blocking urine flow may be drained
- Tolvaptan, a medicine that can slow cyst growth and kidney decline in some adults at risk of fast progression. It needs liver blood tests and increases urine and thirst
- or a kidney transplant if the kidneys fail. A transplant from a living donor is generally preferred
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“If both parents are healthy, a child cannot have PKD.”What is true?
Fact
The rare recessive form affects a child whose parents are both unaffected carriers of a changed gene, and it usually shows in infancy. The common dominant form can also begin as a new change in the gene, although most cases are passed on by a parent who has it.
Myth“No symptoms means no problem, so there is no need for tests.”What is true?
Fact
The common adult form often causes no signs for many years, even while the cysts are growing. High blood pressure often appears early and needs treating to protect the kidneys. When PKD runs in the family, blood pressure checks and screening matter even if you feel well.
Myth“A special diet or a herbal remedy will make the cysts go away.”What is true?
Fact
No diet or home remedy has been shown to dissolve the cysts. Careful blood pressure control, eating less salt and treating complications protect the kidneys, and a kidney specialist can advise whether a medicine that slows the disease is suitable.
Myth“Testing relatives is pointless, because nothing can be done anyway.”What is true?
Fact
Finding PKD early means blood pressure can be checked and treated, and complications can be watched for. People with a family history who plan to have children may also want genetic counselling.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
Will my children get PKD?
It depends on the type. In the common dominant form, a person with PKD can pass the gene change to a child. In the rare recessive form, both parents carry a changed gene, though they are usually unaffected. A genetic counsellor can explain the chances for your family and when testing makes sense.
Does PKD always lead to kidney failure?
PKD progresses slowly and may eventually cause kidney failure, and treatment can relieve symptoms for many years. Controlling blood pressure is one of the most important steps. If the kidneys do fail, dialysis and kidney transplant are options.
Is there a diet for PKD?
No diet removes the cysts. Doctors usually advise less salt to help control blood pressure, within a healthy pattern such as the DASH plan, which is rich in vegetables, fruit and whole grains. Ask your kidney specialist about how much to drink and any other changes.
Can PKD affect other organs?
Yes. Cysts often form in the liver, and PKD can be linked to aneurysms in the brain or aorta, heart valve problems and small pouches in the wall of the colon. Your doctor will decide whether you need any extra checks.
