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polycystic disease of the kidneys
Polycystic kidney disease (PKD) is an inherited condition that results in abnormally formed kidneys. It also causes other abnormalities throughout the body.
What is going on in the body?
Polycystic kidney disease has three forms: infantile, childhood, and adult. The forms are named this way because of the time during a person's life when symptoms begin. The earlier symptoms begin, the more severe the disease usually is. All three forms are inherited from either one or both parents, depending on the type of PKD.
Polycystic kidney disease results in malformed kidneys, which are filled with small sacs, or cysts, instead of normal kidney tissue. This leads to kidney problems including kidney failure, which can lead to death. Abnormalities in other areas of the body may also occur.
What are the signs and symptoms of the disease?
Signs and symptoms depend on the type of polycystic kidney disease. Children with the infantile form of PKD often have very large, malformed kidneys at birth. These children are usually critically ill because their lungs don't development correctly due to the PKD. Most affected children die in the first few days of life.
Children with the childhood form of PKD usually get symptoms before adulthood. They often have kidney failure which causes: In addition, these children often develop scar tissue in the liver that can cause liver failure or bleeding in the gut. Many children die from infections, kidney failure, or liver failure before or during early adulthood. Other children have a milder course and may even have no symptoms until adulthood.
The adult form of PKD is the most common form. Signs and symptoms do not usually begin until adulthood and may include:
What are the causes and risks of the disease?
- high blood pressure
- blood in the urine
- flank pain, or pain on the side of the abdomen
- symptoms of kidney failure, which include fatigue, nausea, vomiting, and loss of appetite
- itching, shortness of breath, and loss of the sex drive may also occur
- repeated kidney infections or kidney stones
- stroke, or lack of blood flow to the brain. This is caused by abnormalities in the arteries in the brain because of PKD. The arteries may form abnormal areas of widening, called cerebral aneurysms, which can burst and cause life-threatening bleeding into the brain.
All forms of polycystic kidney disease are inherited. In order for a child to inherit the infantile or childhood form of PKD, he or she must receive an abnormal gene from both parents. This form of inheritance is called autosomal recessive. Each parent has one abnormal gene and one normal gene, but neither parent has the disease itself. However, the parents may both pass the abnormal gene on to their children, causing the child to have PKD.
The adult form of PKD only requires one abnormal gene, which can come from either parent. This type of inheritance is called autosomal dominant. In this situation, the parent with the abnormal gene has PKD. Because he or she also has a normal gene, however, not all of the person's children are affected.
What can be done to prevent the disease?
Polycystic kidney disease cannot be prevented in a person who has already been born. Genetic counselling may be helpful for couples with a family history of PKD.
How is the disease diagnosed?
Diagnosis is usually based on the family history, physical examination, and imaging tests. Ultrasound and CT scans are commonly used imaging tests to show the kidney abnormalities.
In difficult cases without the usual findings, a kidney biopsy may be needed to make the diagnosis. This is a procedure that involves inserting a special needle through the skin and into the kidney. The needle is used to remove a tiny piece of the kidney, which can be sent to the laboratory for evaluation and testing.
What are the long-term effects of the disease?
The infantile form of PKD almost always leads to death because of lung and breathing problems. The childhood form also commonly leads to death due to infection, kidney failure or liver failure. Those who survive often need dialysis or a kidney transplant. The adult form can lead to the need for dialysis or a kidney transplant, strokes, or chronic pain in the abdomen.
What are the risks to others?
Polycystic kidney disease is not contagious. Those who are affected may pass the condition on to their children in some cases.
What are the treatments for the disease?
Polycystic kidney disease cannot be cured or reversed, so treatment is directed at the problems that occur. High blood pressure is treated with medications. dialysis or kidney transplant may be needed for those who develop kidney failure. Surgery to remove a kidney may be needed if long-term abdominal pain occurs.
Other treatment may be needed for liver disease. Sometimes, surgery is needed to treat any abnormal brain arteries, or cerebral aneurysms. Kidney infections are common and are treated with antibiotics. Other treatments may also be needed in some cases.
What are the side effects of the treatments?
Side effects depend on the treatments used. For example, medication for high blood pressure may cause fatigue, allergic reactions, or erectile dysfunction. Antibiotics can cause stomach upset, allergic reactions, and other effects. Surgery carries a risk of bleeding, infection, and allergic reaction to anaesthesia. Dialysis has many side effects, including infection, salt imbalances, and weakness.
What happens after treatment for the disease?
Treatment usually lasts for life, because polycystic kidney disease cannot be cured and usually gets worse over time.
How is the disease monitored?
Blood tests are often used to monitor kidney function before kidney failure occurs. Blood tests also help to monitor someone on Dialysis. Other monitoring depends on the complications that develop. Any new or worsening symptoms should be reported to the doctor.
Author: Adam Brochert, MD
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Potential conflict of interest information for reviewers available on request