Pyruvate kinase deficiency in cats is a rare genetic disease first described in 1992.
Here you will learn about the symptoms of this disease, how it is diagnosed and recommended treatments.
Key takeaways
- Pyruvate kinase deficiency in cats is a rare hereditary disease that causes the premature breakdown of red blood cells, leading to hemolytic anemia.
- Symptoms can range from mild to severe and may include lethargy, pale gums, jaundice, weight loss, and enlarged spleen, although some cats show no obvious signs.
- There is no cure for PK deficiency, but supportive care, such as blood transfusions, stress reduction, and sometimes splenectomy, can help manage the condition and improve quality of life.
What is pyruvate kinase deficiency in cats?
Erythrocyte pyruvate kinase deficiency (PK deficiency) is an inherited disease in cats.
When a cat lacks the enzyme pyruvate kinase, it has hemolytic anemia, which means its red blood cells are destroyed.
Pyruvate kinase is important for metabolic processes in cells. Red blood cells use this enzyme to release their energy. In cats with PK deficiency, red blood cells do not have the energy to carry out their normal cellular processes, so they die prematurely (hemolysis).
Because there are fewer red blood cells, the cat suffers from anemia. When a cat is anemic, its blood cannot carry as much oxygen to the body's tissues.
If your cat shows signs of anemia or blood loss, it is an emergency.
There are other causes of feline hemolytic anemia that are much more common than PK deficiency. Some of them can be fatal.
Symptoms of Pyruvate Kinase Deficiency in Cats
Not all cats with PK deficiency will show symptoms.
In a study of 25 cats with PK deficiency, 11 cats showed no signs according to their parents.
In those who do show signs, the clinical symptoms of PK deficiency in cats are related to anemia and red blood cell destruction. Symptoms can range from mild to severe.
Common symptoms of PK deficiency include:
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Pale mucous membranes (gums, inner eyelids, genitals)
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Jaundice (yellowing of the eyes, gums, skin)
Symptoms usually develop when the cat is younger, usually around 3 years of age.
However, the age of onset can vary considerably. Some cats don't show any signs until they are 5 years old.
In some cases, a stressful situation, such as childbirth or overheating, seems to trigger the appearance of clinical signs.
Causes of Pyruvate Kinase Deficiency in Cats
PK deficiency in cats is hereditary.
To be affected by this disease, cats must receive the mutated gene responsible for PK deficiency from their mother and father.
Cats that have inherited a gene responsible for the disease can pass it on to their offspring.
Cat breeds that have higher rates of pyruvate kinase deficiency include:
Cat breeds developed from the Abyssinian can also carry the genetic mutation.
Other breeds known to carry the mutation include:
Diagnosis of pyruvate kinase deficiency in cats
As mentioned previously, there are other diseases more common than PK deficiency that can cause hemolytic anemia (destruction of red blood cells) in cats.
This means that your pet's veterinarian will want to rule out other conditions before proceeding with genetic testing, especially if your cat is not a purebred Abyssinian or Somali.
Your veterinarian will start with a physical exam. They may notice some of the symptoms described previously, such as pale gums, jaundice, or an enlarged spleen.
When they recommend blood tests, they may discover:
These findings suggest hemolytic anemia, which could be further assessed by examining a blood sample under a microscope.
Your vet will want to rule out other conditions, so they may also recommend:
During the exam, you should tell your veterinarian any information you know about your cat's genetic lineage.
Be sure to let them know if your cat has recently been vaccinated or taken a new medication so they can rule out any reactions to the vaccine or medications.
To confirm the diagnosis, the veterinarian may send a sample for genetic testing. These tests may use blood or cells taken from inside the cat's cheeks or gums.
Treatment of Pyruvate Kinase Deficiency in Cats
Cats with PK deficiency cannot be cured of this disease. Treatment focuses on managing symptoms and prolonging life.
During a hemolytic crisis characterized by severe destruction of red blood cells, blood transfusions may be necessary, in addition to hospitalization for oxygen therapy. Stressful situations should be avoided to avoid triggering a serious hemolytic event.
Some cats are given steroids like prednisolone, especially if the illness is misinterpreted as immune-mediated hemolytic anemia (IMHA).
There may be a temporary or partial response to steroids, but they will not improve the cat's condition as much as they would with IMHA.
If the spleen becomes too enlarged, surgical removal may be recommended (splenectomy). The spleen is one of the sites where red blood cells are destroyed. The goal of this surgical procedure is therefore to eliminate a major site of red blood cell destruction.
Removal of an enlarged spleen could also improve appetite by decreasing the physical pressure placed on the stomach by the enlarged organ.
In severe cases with recurrent episodes of hemolysis, humane euthanasia may be recommended.
Recovery and Management of Pyruvate Kinase Deficiency in Cats
Cats who suffer from mild anemia or intermittent anemia can often live long and somewhat normal lives. If a cat suffers from severe anemia and requires frequent hospitalizations or blood transfusions, its lifespan will likely be shortened.
For cats that don't eat much, the veterinarian may recommend the use of mirtazapine (used in Mirataz) to improve appetite.
Consider placing pheromone diffusers (like the Feliway Optimum) around the home to further reduce anxiety.
During expected stressful times, such as moving to a new home, ask your veterinarian if an anti-anxiety medication like gabapentin might help your PK-deficient cat.
Prevention of pyruvate kinase deficiency in cats
PK deficiency is something that is inherited, not something that is contracted or caught from other cats.
This means that if your cat is born with this condition, there is nothing you can do to prevent it.
Cats from breeds known to have PK deficiency should be genetically tested before breeding. Affected and carrier cats should be sterilized to avoid passing PK deficiency to their offspring.
FAQs on Pyruvate Kinase Deficiency in Cats
What breed of cat has pyruvate kinase deficiency?
Abyssinian and Somali cats are most commonly affected, although domestic shorthair cats and several other breeds have also tested positive for PK deficiency.
