Polycystic (polly-SIS-tick) kidney disease (PKD) is a genetic disease. This means that it is caused by a problem with your genes. PKD causes cysts to grow inside the kidneys. These cysts make the kidneys much larger than they should be and damage the tissue that the kidneys are made of. PKD causes chronic kidney disease (CKD) , which can lead to kidney failure, or end-stage renal disease (ESRD). PKD causes about 2 percent (2 out of every 100) of the cases of kidney failure in the United States each year.
There are two types of PKD: autosomal dominant PKD and autosomal recessive PKD. Autosomal dominant PKD causes cysts only in the kidneys. It is often called “adult PKD,” because people with this type of PKD might not notice any symptoms until they are between 30 and 50 years old. Autosomal recessive PKD causes cysts to grow in both the kidneys and the liver. Autosomal recessive PKD is often called infantile PKD because babies can show signs of the disease in their first few months of life, or even before they are born.
- What are cysts?
- What causes polycystic kidney disease (PKD)?
- Can PKD be prevented?
- What is the difference between autosomal dominant PKD and autosomal recessive PKD?
- Is acquired cystic kidney disease a type of PKD?
- What causes autosomal dominant PKD?
- How will I know if I have ADPKD?
- What are the complications of ADPKD?
- What is the treatment for ADPKD?
- What causes autosomal recessive PKD?
- How will I know if I am a carrier?
- How will I know if my child has ARPKD?
- What are the complications of ARPKD?
- What is the treatment for ARPKD?
- Where can I get more information?
What are cysts?
Cysts (pronounced sists) are sacs of fluid. In people with PKD, many cysts grow inside of their kidneys, making the kidneys much larger than they should be. The cysts caused by PKD grow from the tiny filters in the kidneys, called nephrons. People with PKD can have thousands of cysts in their kidneys at once. A kidney that is filled with cysts can weigh up to 30 pounds.
What causes polycystic kidney disease (PKD)?
People who have PKD were born with it. PKD is almost always inherited from a parent or from both parents. People of all genders, ages, races, ethnicities and nationalities can have PKD. Men and women get PKD equally as often. If you have a blood relative with PKD, you are more likely to have PKD or carry the gene that causes it. If you carry the gene that causes PKD but you do not have the disease, you are called a carrier. This is possible with autosomal recessive PKD.
Can PKD be prevented?
There is no way to prevent either form of PKD. If you have PKD, you may be able to keep your kidneys working longer by following a healthy lifestyle. Some tips for living healthy include:
- Keep a healthy blood pressure.
- Keep a healthy blood sugar level.
- Keep a healthy weight.
- Follow a low-salt, low-fat diet.
- Limit alcohol.
- Do not smoke or use any tobacco product. If you smoke or use tobacco, quit now.
- Exercise for at least 30 minutes a day, most days of the week.
- Take all prescription medicines as your doctor tells you to.
- Do not take more than the recommended dose of over-the-counter medicines.
What is the difference between autosomal dominant PKD and autosomal recessive PKD?
Autosomal dominant PKD (ADPKD) is the most common type of PKD. About 9 out of every 10 people with PKD have the autosomal dominant form. It is also the most common inherited kidney disease. ADPKD causes cysts to form only in the kidneys and symptoms of the disease may not appear until a person is between 30 and 50 years old.
Autosomal recessive PKD (ARPKD) is a much less common form of PKD. ARPKD causes cysts to form in both the kidneys and the liver. Symptoms of the disease can begin even before birth and can cause life-threatening problems in infants.
Is acquired cystic kidney disease a type of PKD?
Acquired cystic kidney disease (ACKD) is not a type of PKD. While ACKD does cause cysts to form inside the kidneys like PKD does, people with PKD are born with it and people with ACKD are not. Instead, ACKD is caused by chronic kidney disease (CKD) or kidney failure/ESRD. ACKD is more common in people who have had kidney disease for a long time. ACKD happens most often in people who are on dialysis, but the cysts are not caused by dialysis treatments. The National Institute of Diabetes and Digestive and Kidney Diseases has more information about ACKD.
What causes autosomal dominant PKD?
ADPKD is caused by a problem with a specific gene. It is almost always inherited from a parent who also has ADPKD. To inherit the disease, a child needs to have just one parent with ADPKD. A child who has one parent with ADPKD has a 50/50 chance of inheriting the disease. If both parents have ADPKD, their child will be born with the disease.
The genetic problem that causes ADPKD can sometimes happen on its own, meaning that a child may be born with ADPKD, even though neither parent has it. This happens in only 1 out of every 10 cases of ADPKD.
How will I know if I have ADPKD?
Children sometimes have symptoms of ADPKD, but people with the disease usually do not notice symptoms until they are between 30 and 50 years old. Symptoms might include:
If you have any of these symptoms, contact your health care provider. He or she may want to test for kidney problems. If your health care provider thinks ADPKD may be causing your symptoms, he or she may want you to have one or more of the following tests:
- Imaging tests, such as ultrasound, CT scans and MRI scans
- Genetic tests, using a sample of your blood or saliva (spit)
The imaging tests may be done to look for visible signs of cysts in your kidneys. The genetic tests can tell your doctor exactly what kind of PKD you have or if you are likely to develop the disease in the future. It can take months to get the results of genetic tests.
What are the complications of ADPKD?
- Kidney failure/ESRD
- Urinary tract infections
- Kidney stones
- Liver cysts
- Cysts in your pancreas
- Heart valve problems
- Colon problems
- Brain aneurysms
- A serious pregnancy problem, called preeclampsia (in pregnant women who have ADPKD and high blood pressure)
What is the treatment for ADPKD?
There is no treatment or cure for the genetic problem that causes ADPKD. However, your doctor can help you feel better and keep you as healthy as possible by treating your symptoms. For example, if you have a urinary tract infection, your doctor or health care provider might tell you to take an antibiotic medicine to treat it. If you have high blood pressure, your doctor or health care provider might recommend that you change your diet and take a medicine to help lower your blood pressure.
What causes autosomal recessive PKD?
Like ADPKD, autosomal recessive PKD (ARPKD) is an inherited disease. In this case, however, a child may be born with the disease only if both parents are carriers of the gene that causes it. A carrier is someone who has the gene, but does not have the disease. When both parents are carriers of the gene that causes ARPKD, their child has a 1 in 4 (25 percent) chance of being born with ARPKD. The child has a 1 in 2 (50 percent) chance of being a carrier of the gene that causes ARPKD and a 1 in 4 (25 percent) chance of neither having the disease nor being a carrier of the gene. The disease usually does not affect every generation of a family.
How will I know if I am a carrier?
The only way to know if you are a carrier of the gene that causes ARPKD is to have genetic testing. Testing can be done using a sample of your blood or saliva. The test looks for a specific gene called PKHD1. If you have this gene, but do not have ARPKD, you are a carrier.
How will I know if my child has ARPKD?
Signs and symptoms of ARPKD are often noticeable even before a baby is born. Pregnant women receiving prenatal care have regular ultrasounds. The ultrasound images can show that the unborn baby’s kidneys are larger than they should be, which can be a sign of ARPKD.
Another sign of ARPKD is a lack of amniotic fluid in the womb. Amniotic fluid is the liquid that surrounds and protects the baby in the mother’s womb. In the early months of pregnancy, the mother’s body makes the amniotic fluid. In the middle to later months of pregnancy, when the baby’s kidneys begin to work, they make the amniotic fluid. Some babies with ARPKD have badly damaged kidneys, even before birth, and their kidneys cannot make enough amniotic fluid. Ultrasound images can show that there is not enough amniotic fluid around the baby.
If a baby is born with ARPKD, signs of the disease at birth may include:
- Swollen belly
- High blood pressure
- Breathing problems
- Vomiting of breast milk or formula after feeding
- Problems with the growth of the baby’s face and limbs
Children with ARPKD may not show any symptoms. Children with more severe ARPKD may show signs of kidney and liver problems, such as:
- High blood pressure
- Urinary tract infections
- Back or side pain
- Varicose veins
- Lower than average height and weight
What are the complications of ARPKD?
Children with more severe ARPKD usually face more serious complications than children with mild cases of ARPKD. In general, the disease tends to be most severe among children who show symptoms before they are born. Babies with very severe ARPKD may die just hours or days after birth. About 30 percent of newborns with ARPKD die within their first month. About 82 percent of babies who survive past the first month are still alive at age 10. Children with ARPKD may also have any of the following complications:
- Kidney failure before reaching adulthood
- Liver damage that gets worse over time
- High blood pressure
- Urinary tract infections
What is the treatment for ARPKD?
There is no cure for ARPKD. Treatment of people with the disease focuses on managing symptoms and treating complications. Depending on the child’s symptoms and complications, treatment might include:
- Dialysis (usually peritoneal dialysis, but some children have hemodialysis)
- Kidney transplant
- Growth hormones
- Blood pressure medicine
- Antibiotic medicines
- Combined liver and kidney transplant