Polycystic Kidney Disease

Polycystic kidney disease, also known as PKD, is a genetic disease that is passed down from parent to offspring. The disease is primarily found in Persian cats but the disease also affects other breeds and some dogs. This genetically inherited disease causes multiple cysts to form in the kidneys. This cyst is a small sac-like pocket of tissue that contains fluid.

Because PKD is a genetic disease, animals with this disease will be born with cysts on their kidneys. They’ll be too small to diagnose until your puppy or kitten is at least 6 months old. Depending on the progression of the disease it is usually noticed when your pet is between 3 and 10 years of age. About 7 years old seems to be when it’s noticeable in most cats that have PKD. PKD will only be seen when the cysts become larger and compress the tissue in the kidneys. This kidney compression will lower the effectiveness of kidney functions, eventually causing kidney failure.

The disease is caused by the presence of the PKD1 gene which occurs due to a gene mutation. Any cat or dog with the PKD1 mutation will inherit PKD, even if only a single parent was a carrier of this gene.

Symptoms of PKD

The symptoms of Polycystic Kidney Disease vary from one animal to another, but the infected pet will still have some of the common symptoms. These symptoms include:

  • Polydipsia (Unusual increase in thirst)
  • Polyuria (increase in urination)
  • Anemia (lack of healthy red blood cells)
  • Diarrhea
  • Pain
  • Nausea
  • Vomiting
  • Decreased appetite
  • Lethargy
  • Blood in the urine or vomit
  • High blood pressure 
  • Anorexia (Extreme weight loss)
  • Listlessness
  • Blindness
  • Seizures
  • Ataxia (lack of control of body)

Stages of the disease PKD

Stage 1

Blood tests may show an increase in creatinine level in blood, a waste by-product of muscle metabolism. Other symptoms like blood in their urine and vomit, lethargy, and listlessness also occur.

At this stage the signs usually go unnoticed and your pets kidneys will function somewhere between 90% and 100%

Stage 2

Stage two happens when Mild Renal Azotemia is noticeable, even if it is not detected. Blood Urea Nitrogen (BUN) levels are elevated along with high blood pressure and possibly diarrhea.

Stage 3

Moderate Renal Azotemia, a further increase in Blood Urea Nitrogen levels along with an increase in creatinine in the blood.

Increased urination, pain, and increased thirst are also observed, along with decreased appetite.

Stage 4

Severe Renal Azotemia happens at stage four, with an abnormal amount of Blood Urea Nitrogen and too much creatinine in their blood. These levels will be highly elevated because your pet’s kidneys will be functioning at 15% or less at this point. When they function this poorly the kidneys cannot filter out and remove nitrogen or creatinine from their blood. By this stage, your pet will have almost all the symptoms. Your pet’s life expectancy will be very short once they get to this stage.

Treatment for PKD

Specific treatments, especially for Polycystic kidney disease, follow the same treatment pattern as chronic kidney failure (CKD) or chronic renal failure.

These treatments include:

Special Diet

Cats and dogs with PKD are given special diets with less phosphorus, protein, and sodium. It’s very important to minimize the amount of phosphorus in your pets diet. The lower the phosphorus level, the slower the progression of kidney disease, and the longer they’ll have a quality life.

Protein contributes to waste build up in your pet’s blood. The lower the protein in their food the less waste that will build up, making it easier for their kidneys to filter the waste out. The less waste they have in their blood the better that they’ll feel and less tired they will be. As their kidneys fail, quality of life is important both for you and your pet.

Diets high in salt can make the kidney damage worse because it will increase their blood pressure. Any food you feed your pet should be as low in sodium so that it does not contribute to an increase in their blood pressure.

These restrictions don’t only apply to the food they eat, but any treats you give them. Low phosphorus, low protein and low sodium treats. Cured meats, cheeses and breads as well as most commercial pet treats are off the menu.

The last thing you’ll want to feed your pet will be acidifying pet food. Most commercial pet foods will be acidifying, your vet will need to write your pet a prescription for a non-acidifying pet food. Pets with kidney disease can become too acidic, and this food helps to counter the acidification.

We’ve covered the things your pet shouldn’t eat, but there is one thing that you’ll want to look for that should help them feel better and hopefully also slow the progression of their disease. Omega 3 fatty acids are thought to help. If you can’t find food with this in it, you can always add it and mix it into their food.

Fluid Therapy

Intravenous fluid therapy is the most common treatment for kidney diseases. Kidneys play a considerable role in cleaning their blood. Fluid therapy is similar to what dialysis is in humans. Fluid therapy filters out toxins and helping replace electrolytes, keeping them from getting dehydrated.

The amount of fluid treatment varies depending on the severity of your pet’s kidney failure. Some pets will only receive fluid therapy twice a week, others with more advanced kidney failure will need it every day.

Special Medication 

Medicine can be given to reduce the effects of nausea and vomiting.

Drugs to block absorption of phosphorus can be prescribed as well as pain killers.

Prevention of PKD

Genetic testing of your cat or dog before they breed is the best option, especially if they are Persians. If the DNA test shows the presence of the PKD1 gene, don’t breed your pet or this disease will be passed to a new generation.

Monitoring kidneys for kidney damage could help with early diagnosis, which can be helpful for treatment even if a cure isn’t possible.

Related Questions

How Long can Pets with Polycystic Kidney Disease Live?

Usually cats and dogs with PKD will live a normal life until symptoms show up. The signs usually show up after seven years, but some might be noticeable as early as three years.

Is Polycystic Kidney Disease Painful for Your Pet?

Polycystic kidney disease doesn’t cause a lot of pain until the disease has spread a lot and destroyed kidney tissue. By this stage, kidney failure is almost inevitable.

Is Polycystic Kidney Disease Curable in Cats or Dogs?

Because PKD is a genetic disease; it is impossible to cure it. The treatments can only reduce the effects of the disease on your pet’s health and help them live longer and with less pain.