Pyruvate Kinase Deficiency In Cats
Maine Coon cats are at a higher risk of developing Pyruvate kinase deficiency than other cat breeds. Thankfully, this disorder is not necessarily a death sentence, but cats with this condition require a lot of extra care.
There is no cure for pyruvate kinase deficiency, but a Maine Coon with this condition can still live a long, happy life.
Pyruvate Kinase Deficiency In Maine Coon Cats
Pyruvate kinase deficiency is a kind of anemia where the affected cat cannot produce enough of the enzyme pyruvate kinase. This enzyme produces energy for red blood cells, and without it, their lifespan is reduced. Without sufficient red blood cells, affected cats suffer from anemia, leading to weakness, weight loss, and other symptoms.
These gorgeous, long-haired cats are not just prized for their appearance; instead, they’re also known for their loving, social nature and patience with children and other pets (oh! and HUGE size!)
As wonderful as Maine Coons are, they are prone to a variety of inherited conditions, including pyruvate kinase deficiency.
Also known as PKD, PKdef, or erythrocyte pyruvate kinase deficiency, this disorder is an inherited type of hemolytic anemia.
Hemolytic anemia specifically refers to a kind of anemia where red blood cells are abnormally destroyed or have a reduced lifespan.
Red blood cells are responsible for the transportation of oxygen and iron throughout the body. Cats that are unable to produce sufficient red blood cells may experience the following:
- Fatigue
- Dizziness
- Jaundice
- Other Symptoms
PKdef is a specific kind of hemolytic anemia, where the body lacks the enzyme pyruvate kinase. This enzyme allows red blood cells to metabolize energy.
In cats with PKdef, this enzyme is not sufficiently active, which means that the affected cat’s red blood cells become unstable and have significantly shorter lifespans.
There is no way to get rid of PKD, though it is possible to catch it early through Maine Coon health tests.
Responsible breeders will conduct genetic testing on all of their cats before breeding them, to prevent passing on any disorders to their offspring (source 1,2,3).
Causes
PKDef is an inherited disorder. This condition is recessive, therefore for a cat to have PKdef it must inherit two copies of the gene. Both parents must carry at least one copy of the gene for their offspring to have pyruvate kinase deficiency.
If a cat only inherits one copy of the gene from its parents, it becomes a carrier. This means that while this cat will not have PKdef, they can still pass it to their offspring.
PKdef is more common in Maine Coons than other cat breeds since breeding cats to have specific characteristics means that many fanciers will breed cats that are closely related.
When there is only a small selection of cats that have certain desirable characteristics, they are also more likely to pass on genetic disorders to their offspring.
Diagnosis
The surest way to diagnose PKDef is through genetic testing. To test for PKdef provide a sample of your cat’s DNA, typically a blood sample or a cheek swab.
This sample is then analyzed and will reveal if your cat carries one copy or two copies of the gene responsible for pyruvate kinase deficiency (source 1,2).
Symptoms
Pyruvate kinase deficiency is a complicated disorder resulting in various symptoms.
Cats can also experience varying levels of severity of PKdef; some only have mild anemia, while others can have severe anemia.
Typically, symptoms begin between one month and five years, though the common PK symptoms below often begin between 1.5 and 3 years:
1. Intermittent Periods Of Anemia
Depending on the severity of the condition, cats with PKdef typically have wavering periods of anemia, particularly early on.
Without the enzyme pyruvate kinase, the red blood cells are unable to metabolize energy and die off quickly. Without sufficient red blood cells to carry oxygen throughout the body, the cat will experience anemia.
However, the body is still able to produce red blood cells through bone marrow, and after a period of anemia, a cat may appear to return to normal as more red blood cells enter the bloodstream.
Over time, however, the lack of sufficient pyruvate kinase will cause these red blood cells to die prematurely, as well.
Cats with mild to moderate PKdef will often experience anemia for short periods before the body sends out more red blood cells.
Until, eventually, their bone marrow is no longer able to keep up with the continuous loss of red blood cells.
2. Lethargy
Since red blood cells are responsible for transporting oxygen, a cat suffering from PKdef will often feel tired and weak.
You may notice your cat has difficulty playing as it once did, easily becoming exhausted after running or chasing.
Anemia can also cause your cat to breathe rapidly in an attempt to get more oxygen.
3. Pale Gums
Healthy cats have pink gums because their blood is well-oxygenated.
Cats with PKdef, however, lack sufficient oxygen in their blood, and their gums may appear pale.
Other areas of exposed skin may also appear place, such as the:
- Paw Pads
- Eyes
- Ear Flaps
Pale gums can indicate serious illness in a cat, so if you notice this symptom, take your cat to the vet straight away.
4. Jaundice
Red blood cells contain a yellow substance known as bilirubin.
When red blood cells are broken down, they release this substance into the bloodstream.
Since cats with PKdef lose an abnormal amount of red blood cells, they are more likely to contain high amounts of bilirubin, leading to jaundice.
In cats, it is easiest to find signs of jaundice in the following places:
- Paw Pads
- Ear Flaps
- Gums
- Eyes
5. Loss Of Appetite And Weight Loss
PKdef is likely to cause a loss of appetite or a seeming disinterest in food. As a result, the affected cat can begin to lose weight, as well.
Other underlying conditions, such as hyperthyroidism or cancer, can exacerbate these symptoms and lead to extreme weight loss.
6. Unkempt Coat
Your cat’s coat may appear dull and unkempt.
This is a common sign of illness in cats because, as they struggle with lethargy and lack of appetite, they no longer have the energy to properly care for their fur.
7. Pica
Although more common in cats suffering from iron-deficiency types of anemia, cats with PKdef can also struggle with pica.
Pica refers to the ingestion of inedible objects, most commonly fur and cat litter.
A cat struggling with anemia will try to ingest inedible items to gain more nutrients, in an attempt to replenish its red blood cells.
8. Enlarged Abdomen
A relatively rare sign of PKdef in cats is an enlarged abdomen, due to swelling in the spleen and sometimes the liver.
The spleen traps and removes old red blood cells. However, since a cat with PKdef suffers from the excessive destruction of these red blood cells, the spleen may be unable to effectively break down all of the red blood cells.
If you notice any worrying symptoms in your cat, you should take them to the vet right away.
Consider Maine Coon genetic testing if you are concerned your cat may be suffering from PKdef.
Knowing for sure if your cat has PKdef is the first step in treating and managing this condition (source 1,2).
Treatment
As heartbreaking as a pyruvate kinase deficiency diagnosis can be, it is not a death sentence! Firstly, PKdef can have varying levels of severity, and cats with mild or moderate anemia can still live long healthy lives.
Sadly, there is no cure for PKdef, but symptoms can still be managed. Even cats with severe PKdef can benefit from a variety of treatment options.
Below are some treatment options for Maine Coon PK:
Patient-Specific Treatment
There is not one catch-all way to treat PKdef, but it is possible to manage symptoms. This will, of course, vary based on the symptoms present in your cat.
Cats with cardiac problems or breathing difficulties will need very different treatment from cats dealing with weight loss and appetite loss.
Your vet will be able to provide a more comprehensive plan for your cat depending on its unique situation.
Blood Transfusion
It is possible to perform blood transfusions, exchanging your cat’s blood for blood that is rich in healthy red blood cells.
This is typically only done in severe cases, however, and it can be a stressful and uncomfortable process for your cat.
Splenectomy
The spleen is responsible for destroying old red blood cells, but since cats with PKdef are in desperate need of red blood cells, the spleen can actually make symptoms worse.
The spleen can also become overloaded with red blood cells and swell in size.
In severe cases, some veterinarians may recommend a splenectomy, which is the removal of the spleen.
It is important to note, however, that splenectomies should not be taken lightly. This is an invasive operation with a risk of death, as well as a long and painful recovery period.
Humane Euthanasia
Many cats with PKdef live long, healthy lives.
However, in more severe cases, the symptoms of anemia are simply too much for a cat to bear.
As much as we all love our pets, it is sometimes kinder to let them go, so they do not have to suffer anymore.
Euthanasia is a big decision, and you might want to consider consulting multiple veterinarians.
After all, every case of pyruvate kinase deficiency is different, and your cat will need unique care depending on its situation.
Is It Reversible?
Sadly, because pyruvate kinase deficiency is a genetically inherited disorder, there is no way to reverse it or get rid of it.
It is possible to treat the symptoms of PKdef, but there is no way to fix the underlying cause of insufficient pyruvate kinase.
Is It Fatal?
There is no way to cure this disorder but the situation is not necessarily hopeless. Unlike dogs, cats with PKdef do not develop liver failure or osteosclerosis, and some can live for many happy years.
Pyruvate kinase deficiency life expectancy varies depending on the situation, as cases can range from mild to severe. Severe cases of PKdef can lead to premature death, sometimes as early as two years or younger.
Mild or moderate cases, however, often result in intermittent anemia because, even though the lack of pyruvate kinase does result in the early destruction of red blood cells, the affected cat can still produce red blood cells through their bone marrow.
Their anemia can come in waves, allowing the affected cat time to rest and recover during non-anemic periods. Surprisingly, in some mild cases, owners may never notice symptoms at all.
The affected cat may suffer from lethargy and other mild symptoms but is still able to function day each day. As cats with PKdef grow older, however, the disorder will take more and more of a toll on their body.
Senior cats with PKdef will likely die from this condition, but you will still have many long, happy years to spend with your cat (source 1).
Diseases Associated With PKD
The erythrocyte pyruvate kinase deficiency mutation identified in multiple breeds of domestic cats often leads to a wide array of varying symptoms and complications.
Here are some conditions that PKdef can cause:
- Anemia
- Splenomegaly
- Heart Murmur
Keep reading to discover more about these specific health issues:
Anemia
The most common disease related to pyruvate kinase deficiency is anemia.
Anemia refers to an insufficient number of red blood cells which, in this case, is caused by the lack of the enzyme pyruvate kinase.
Cats with anemia do not have enough blood cells to carry sufficient oxygen and iron, and will often become lethargic, dizzy, and weak as a result.
Splenomegaly
The spleen is responsible for destroying old red blood cells.
Since cats with PKdef already do not have enough blood cells, to begin with, the spleen can exacerbate this anemia.
The spleen can also become enlarged as it becomes overloaded with “dying” red blood cells, a condition known as splenomegaly.
In severe cases, the spleen may need to be surgically removed.
Heart Murmur
PKdef can also lead to a variety of cardiac problems, including heart murmurs.
Since red blood cells transport oxygen throughout the body, PKdef will not just affect the lungs.
This also affects the cardiovascular system, which can take a big toll on the heart.
How Does PKD Cause Hemolytic Anemia?
There are many different kinds of anemia, including:
- Iron-Deficiency Anemia
- Sickle Cell Anemia
- Hemolytic Anemia
Hemolytic anemia specifically refers to types of anemia where the red blood cells are abnormally destroyed or have a reduced lifespan.
As a result, the body is unable to produce sufficient red blood cells to make up for this loss, leading to anemia.
The cause of hemolytic anemia in pyruvate kinase deficiency is the lack of activity in the enzyme pyruvate kinase.
When fully functional, this enzyme allows red blood cells to metabolize energy.
In cats with PKdef, however, this enzyme is not active enough, and red blood cells become unstable and “die” much faster than they should (source 1).