Hypokalemia (low blood potassium) in Cats

Overview of Low Blood Potassium in Cats

Hypokalemia is an abnormally low concentration of potassium in a cat’s blood. The normal potassium level in cats is around 3.5 to 5.1 mEq/L. Levels less than 3.5 mEq/L are diagnosed as hypokalemia.

Potassium is an electrolyte that is vital to the normal function of various organs, such as the heart, gastrointestinal tract and muscles. In order for the body to keep potassium levels within the normal range, the amount of potassium ingested must be equal to the amount of potassium lost in the urine and gastrointestinal tract. Although loss of potassium is a normal part of metabolism, animals that are ill often lose potassium excessively. If the cat is unable to ingest enough potassium to keep up with excessive losses, hypokalemia can develop.

Hypokalemia is a symptom and many diseases can result in low potassium levels. The most common cause is chronic kidney failure but diabetes, hyperadrenocorticism, hyperaldosteronism and hyperthyroidism can also result in low blood potassium. Animals with persistent vomiting, diarrhea or hyperglycemia can also develop hypokalemia, and an inherited hypokalemia can affect Burmese cats.

Hypokalemia has various effects throughout the body. If mild hypokalemia is present, 3.0 to 3.5 mEq/L, many animals are asymptomatic. Once the potassium level falls below 3.0 mEq/L, clinical signs often develop.

What to Watch For

One classic sign of low blood potassium in cats is a weakness of the muscles, particularly of the neck. Affected cats often hold their necks flexed and are unable to lift their heads. Others include:

• Constipation
• Poor appetite
• Weakness
• Lethargy
• Stiff awkward walk
• Increased thirst
• Increased urination
• Weight loss
• Dehydration

Diagnosis of Hypokalemia in Cats

Hypokalemia and any underlying disease is diagnosed by blood tests. An electrocardiogram (EKG) is performed to determine the effect the low potassium has on the heart.

• The complete blood count often reveals mild anemia, usually associated with underlying kidney failure.
• The biochemical profile reveals low blood potassium levels and confirms the diagnosis. Other abnormalities may also be detected such as kidney failure, diabetes or other diseases.
• The urinalysis may reveal dilute urine associated with kidney failure.
• An electrocardiogram may be performed. If the potassium level is significantly low, serious changes may be seen on the electrical tracing of the heart rhythm.

Treatment of Hypokalemia in Cats

Once diagnosed, cats are treated with either intravenous potassium or oral potassium supplementation. If the low potassium is severe, cats are hospitalized and given potassium supplementation as an intravenous fluid additive. Potassium cannot be given intravenously unless significantly diluted and given slowly. Rapid intravenous administration can lead to severe heart electrical disturbances and may result in death.

Once the severe potassium deficiency is corrected, oral supplementation can begin. Potassium gluconate, Tumil K, is available in oral, liquid and paste form for daily administration at home. Cats are dosed at 2 to 4 mmol per cat per day. Supplementation is often continued throughout life.

Cats often also require treatment for the underlying cause of the hypokalemia.

Many cats respond favorable within 2 to 5 days but complete recovery may take several weeks.

Home Care and Prevention

Cats with hypokalemia are often continued on potassium supplementation throughout their lives. Cats should be monitored for relapse or development of other signs. Many cats have underlying disease, such as kidney failure, and may need additional treatment.

Feeding a high quality diet and supplementing with potassium when needed can prevent hypokalemia and associated signs.