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Polycystic Kidney Disease

What is Polycystic Kidney Disease?

Polycystic kidney disease is a disorder that affects the kidneys and other organs.

Clusters of fluid-filled sacs, called cysts, develop in the kidneys and interfere with their ability to filter waste products from the blood. The growth of cysts causes the kidneys to become enlarged and can lead to kidney failure. Cysts may also develop in other organs, particularly the liver. PKD It is an inherited (i.e. genetically transmitted) disease of the kidneys that may affect up to 1 individual out of 500 in North America. ADPKD is a major cause of advanced kidney failure requiring dialysis or a transplant.

What are the symptoms associated with PKD?

The most common systems of polycystic kidney disease include:

  • Dangerously high blood pressure (hypertension)
  • Pain in the back or sides
  • Blood in the urine (hematuria)
  • Recurrent urinary tract infections
  • Kidney stones
  • Headaches
  • Heart valve abnormalities.

Additionally, people with polycystic kidney disease have an increased risk of an abnormal bulging (an aneurysm) in a large blood vessel called the aorta or in blood vessels at the base of the brain. Aneurysms can be life-threatening if they tear or rupture.

How is PKD diagnosed?

PKD is usually diagnosed using standard abdominal imaging with ultrasound, CT scan, or magnetic resonance imaging (MRI).

In ADPKD, kidney cysts have a characteristic distribution, showing symmetrical and diffuse involvement of both kidneys. We are also interested in assessing if you have affected members in your family. If your family history is negative or the cyst distribution is atypical on imaging, we will offer genetic testing to confirm the diagnosis.

What other organs besides the kidney are affected by PKD?

PKD can affect other organs besides the kidney. People with PKD may have cysts in their liver, pancreas, spleen, ovaries, and large bowel.

Cysts in these organs usually do not cause serious problems, but can in some people. PKD can also affect the brain or heart. If PKD affects the brain, it can cause an aneurysm. An aneurysm is a bulging blood vessel that can burst, resulting in a stroke or even death. If PKD affects the heart, the valves can become floppy, resulting in a heart murmur in some patients.

How is PKD managed?

PKD can be managed with the following:  

  • careful control of blood pressure
  • prompt treatment with antibiotics of a bladder or kidney infection
  • lots of fluid when blood in the urine is first noted
  • medication to control pain (talk to your doctor about which over-the-counter medicines are safe to take if you have kidney disease)
  • a healthy lifestyle with regard to smoking cessation, exercise, weight control and reduced salt intake
  • drinking lots of plain water throughout the day
  • avoiding caffeine in all beverages
What are the available treatments?

Tolvaptan, an inhibitor of vasopressin receptors in the kidney tubule, works by diluting the urine which results in a slower rate of cyst growth.

This drug has been approved in Canada, Europe, and Japan for treatment of ADPKD in patients at high risk for progression to advanced renal failure. Other drugs are being studied in ongoing clinical trials. Increasing water intake to at least 3 L per day may be beneficial in slowing cystic disease progression. Caffeine and smoking should be avoided.

Is genetic testing required?

ADPKD is caused by a mutation in one of two genes in your body: PKD1 and PKD2.

The type of ADPKD a person has depends on which gene the mutation is in. When the PKD gene has a mutation, the protein made by this gene will not function properly and will cause the disease. PKD is a dominant gene, so there is a 50% chance of a parent passing the gene to their child. However, 10 to 20% of patients have a “spontaneous” mutation that was not passed on from their parents.  

Genetic testing confirms whether or not a person has ADPKD. However, in a small percentage of patients, the genetic test result can come back negative even though their kidneys have cysts. Genetic testing also provides us with important information on your disease prognosis. The type of mutation can help us predict the likelihood of a person needing dialysis or a transplant earlier or later in life.

We do not recommend genetic testing in patients younger than 18 years of age since the disease is usually mild in children and a positive test may lead to emotional distress or problems with insurability.

How do I find out my prognosis?

We can help determine a person’s prognosis using three sources of information: the type of PKD mutation they have, their total kidney volume and their kidney function. 

PKD2 mutations are often associated with milder disease while PKD1 mutations usually result in severe disease that progress more quickly. Genetic testing will help us to determine the type of mutation you have.

Total kidney volume is measured using a magnetic resonance imaging (MRI) or a CT scan. These scans will allow us to measure the total volume of both your kidneys. Total kidney volume along with your age and kidney function level can help us identify who is at risk for needing dialysis or a transplant in the future. Your kidney function is determined using blood and urine tests to measure the rate at which your kidneys are filtering waste from your body.

Other factors that may also affect the severity of ADPKD include: additional genetic mutations, kidney disease due to diabetes, high blood pressure, disorders of the immune system, or other causes, and environmental factors such as smoking and excessive caffeine intake. 

What is ESRD?

ESRD (or end-stage renal disease) refers to kidney failure where the kidneys are severely damaged and are no longer able to filter water or toxins properly.

As the cysts become larger, they can put pressure on the kidney’s blood vessels and filters. This pressure can cause damage to the surrounding healthy kidney tissue. This damage decreases the kidney ability to function over time and may eventually lead to kidney failure. If a person’s kidneys begin to fail, their kidney specialist will discuss their treatment options with them (i.e. dialysis, transplant, conservative care). 

How can I be referred to the program?

You may ask your physician to complete the online referral form and fax it to our office at 416 340 4999 attention CIMPKD

If you have questions please contact us at cimpkd@uhn.ca and a member of our team will reach out to you and gladly discuss the next steps.