Pyruvate Kinase Deficiency: Common Symptoms and Treatment in Cats

Pyruvate kinase deficiency in cats is a rare genetic disorder first described in 1992. 

Here, you’ll learn the symptoms of this condition, how it’s diagnosed, and recommended treatments. 

What Is Pyruvate Kinase Deficiency in Cats?

Erythrocyte pyruvate kinase deficiency (PK deficiency) is an inherited disorder in cats.  

When a cat has a lack of the enzyme pyruvate kinase, they get hemolytic anemia, which means their red blood cells get destroyed. 

Pyruvate kinase is important for the metabolic processes of cells. Red blood cells use this enzyme to release their energy. In cats with PK deficiency, the red blood cells lack the energy to do their normal cell processes, so they die early (hemolysis). 

Because there are fewer red blood cells, the cat gets anemia. When a cat is anemic, their blood can’t carry as much oxygen to the tissues of the body. 

If your cat is showing signs of anemia or blood loss, this is an emergency.  

There are other causes of feline hemolytic anemia that are much more common than PK deficiency. Some of these can be fatal. 

Symptoms of Pyruvate Kinase Deficiency in Cats

Not all cats with PK deficiency will have symptoms.  

In one study that looked at 25 cats with PK deficiency, 11 cats did not show signs according to their pet parents.  

In those who do show signs, 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:  

• Lethargy and weakness 

• Diarrhea 

• Pale mucous membranes (gums, inner eyelids, genitals) 

• Lack of appetite 

• Poor coat quality 

• Weight loss 

• Jaundice (yellowing of eyes, gums, skin) 

• Eating nonfood items (pica) 

• Enlarged spleen 

• Rapid breathing 

Symptoms usually develop when the cat is younger, typically by the time they’re 3 years old.  

However, the age of onset can vary quite a bit. Some cats don’t show signs until they’re closer to 5 years old.  

In some cases, a stressful situation, such as giving birth or overheating, seems to trigger the onset of clinical signs. 

Causes of Pyruvate Kinase Deficiency in Cats

PK deficiency in cats is inherited.  

To be affected by the condition, cats need to get the mutated gene for PK deficiency from both their mother and father.  

Cats who have inherited one gene for the disorder can pass the gene to their offspring. 

Cat breeds that have higher rates of pyruvate kinase deficiency include: 

• Abyssinian 

• Somali 

• Domestic shorthair and longhair 

Cat breeds developed from the Abyssinian may also carry the gene mutation.  

Other breeds who have been known to carry the mutation include:  

• Australian Mist 

• LaPerm 

• Maine Coon 

• Norwegian Forest 

• Siberian 

• Toyger 

Diagnosis of Pyruvate Kinase Deficiency in Cats

As previously mentioned, there are other diseases that are more common than PK deficiency that can cause hemolytic anemia (red blood cell destruction) in cats.  

This means your pet’s veterinarian will want to rule out other conditions before moving on to genetic testing, especially if your cat isn’t a purebred Abyssinian or Somali. 

Your veterinarian will start with a physical exam. They may notice some of the symptoms described earlier, such as pale gums, jaundice, or an enlarged spleen.  

When they recommend blood work, they may find: 

• Anemia (low red blood counts) 

• Increased numbers of immature red blood cells 

• High globulin levels 

• High levels of bilirubin 

• Increased liver enzymes 

These findings suggest hemolytic anemia, which could be further evaluated by looking at a sample of blood under the microscope.  

Your veterinarian will want to rule out other conditions, so they may also recommend: 

• Checking for blood parasites like Mycoplasma haemofelis  

• Running tests for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) 

• Ruling out toxin exposure 

During the exam, you should tell your veterinarian any information you know about your cat’s genetic bloodline.  

Make sure to let them know if your cat was recently vaccinated or took a new medication so that they can rule out vaccine or medication reactions. 

To confirm the diagnosis, the veterinarian can send off a sample for genetic testing. These tests can use blood or cells brushed from inside the cat’s cheeks or gums. 

Treatment of Pyruvate Kinase Deficiency in Cats

Cats with PK deficiency can’t be cured of the condition. Treatment is focused on managing symptoms and prolonging life. 

During a hemolytic crisis when there is severe red blood cell destruction, blood transfusions may be needed, in addition to hospitalization for oxygen therapy. Stressful situations should be avoided to prevent triggering a severe hemolytic event. 

Some cats are put on steroids like prednisolone, especially if the condition is misinterpreted as an 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 for IMHA. 

If the spleen becomes too enlarged, surgical removal might be recommended (a splenectomy). The spleen is one of the sites where red blood cells are destroyed, so the goal of this surgery is to remove a major site of red blood cell destruction.  

Removing an enlarged spleen might also improve appetite by decreasing physical pressure placed on the stomach by the expanded 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 have mild anemia or anemia that comes and goes can often live long, somewhat normal lives. If a cat has severe anemia and needs frequent hospitalization or blood transfusions, their lifespan is likely to be shortened. 

For cats who aren’t eating much, the veterinarian may recommend the use of mirtazapine (used in Mirataz) to improve appetite. 

An important part of managing a cat with PK deficiency is to reduce stress. Pet parents should provide plenty of activity (toys, cat trees like the TRIXIE Eduardo, etc.) and a predictable routine.  

Consider placing pheromone diffusers (such as the Feliway Optimum) in the home to further reduce anxiety.  

During expected times of stress, such as moving to a new home, speak with your veterinarian about whether an anti-anxiety medication like gabapentin could 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 if your cat was born with the 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 spayed or neutered to prevent passing PK deficiency to offspring.