If you or someone you love has recently been diagnosed with polycystic kidney disease (PKD), you probably have a lot of questions about the disease and what comes next.
One of the most important things to know is that PKD can affect people very differently. Some people have few symptoms for many years, while others experience complications or declining kidney function much earlier. With appropriate care and support, people with PKD can continue to live full and meaningful lives.
The two main types of PKD
There are two main types of PKD: autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD).
Both are genetic diseases. That means they are caused by changes in genes and can be inherited within families. They are not something you can catch from another person or develop because of something you did.
Autosomal dominant polycystic kidney disease (ADPKD)
ADPKD is the most common inherited form of PKD and one of the most common inherited kidney diseases. It is estimated to affect about 1 in 1,000 people worldwide, although many people may not know they have it.
ADPKD often runs in families. If a parent has an ADPKD-causing genetic variant, each biological child has a 50% chance of inheriting it.
You may sometimes hear families say that PKD has “skipped a generation” because one generation seems to be unaffected. Genetically, though, ADPKD does not normally skip a generation: a person either inherits the genetic variant or does not. What can vary greatly is how and when the disease shows up. Someone who inherits the variant may have much milder disease or develop noticeable symptoms much later than other members of their family. In some people, ADPKD can also result from a new genetic change, with no previous known family history of the disease.
ADPKD is progressive, but the rate of progression varies widely. Some people live for many years with few or no symptoms. Others develop high blood pressure, pain, kidney stones, infections or declining kidney function earlier in life.
Some people with ADPKD eventually develop kidney failure and may need dialysis or a kidney transplant. There are also treatments and other approaches that can help manage complications and protect kidney health. For some adults whose ADPKD is at risk of progressing rapidly, a medication called tolvaptan may help slow the decline in kidney function.
Autosomal recessive polycystic kidney disease (ARPKD)
ARPKD is a much rarer form of PKD, affecting approximately 1 in 20,000 to 25,000 live births. It affects all sexes equally.
ARPKD is often diagnosed before birth, during infancy or in childhood, although some people are not diagnosed until later. The disease can affect both the kidneys and liver, and its severity varies considerably.
In its most severe form, ARPKD can cause serious breathing problems in newborns because kidney enlargement and reduced amniotic fluid can affect lung development. About 20% to 30% of affected infants die during the neonatal period or first year of life. Outcomes have improved with advances in neonatal and kidney care.
Among people living with ARPKD, about half develop kidney failure requiring dialysis or a kidney transplant within the first two decades of life. Others maintain kidney function for much longer. Liver complications can also become an important part of ARPKD care.
Symptoms and complications of PKD
PKD affects everyone differently, and not everyone will experience the same symptoms or complications. Depending on the type of PKD and the individual, these can include:
- high blood pressure
- back, side or abdominal pain
- headaches
- an enlarged or swollen abdomen
- blood in the urine
- frequent urination
- kidney stones
- urinary tract or kidney infections
- declining kidney function and, for some people, kidney failure
PKD can also affect parts of the body beyond the kidneys. Your healthcare team can help you understand which complications may be relevant to you and whether any additional monitoring is recommended.
Living well with PKD
A PKD diagnosis may mean making some changes, whether the diagnosis is yours or belongs to someone you love. The goal isn't simply to protect kidney function for as long as possible. It's also to support your overall health and quality of life while living with PKD.
Managing blood pressure is particularly important because high blood pressure is common in PKD and can contribute to kidney and cardiovascular problems. Eating a balanced diet, being physically active, not smoking, taking medications as prescribed, and keeping up with recommended medical care can also help. Your healthcare team can give you advice based on your kidney function, health and stage of PKD.
For answers to some of the questions people most often ask about both forms of PKD, check out our FAQs.
PKD and your family
If PKD runs in your family, you may have questions about whether you or your children should be tested before symptoms appear. This can be a difficult and very personal decision.
Testing for PKD can involve kidney imaging, genetic testing or both, depending on your age, family history and circumstances. Once a diagnosis is confirmed, it becomes part of your medical history. There can be benefits to knowing earlier, including appropriate monitoring and treatment, but there can also be personal, emotional and practical considerations.
A nephrologist or genetic counsellor can help you understand your family's inheritance pattern, your options for testing, and what the results could mean for you or your children.
To find a genetics clinic or genetic counsellor near you, visit the Canadian Association of Genetic Counsellors.