Hypokalemia (Low Potassium Levels) in Cats

What is hypokalemia?

Hypokalemia is a low concentration of potassium in the blood. Potassium is an important electrolyte and is vital for the normal function of muscles and nerves. In some situations, normal control of body potassium concentration is lost, resulting in depletion of potassium and low blood potassium concentrations.

What are the clinical signs of hypokalemia?

Mild to moderate hypokalemia does not usually cause significant clinical signs. However, if severe hypokalemia develops, it can cause profound and life-threatening clinical signs. The main effect of severe hypokalemia is generalized muscle weakness. Affected cats have difficulty getting up and walking and may appear almost "drunk" because of their weakness.

A common and characteristic sign of muscle weakness is the inability to raise the head into a normal position, so that the head is held down or the neck is bent. Hypokalemia can also cause marked depression and lack of appetite. Some cats with hypokalemia may become constipated. In many cases, the cat will have a poor-quality coat.

What causes hypokalemia?

The most common cause of hypokalemia is chronic kidney disease, a common condition in older cats. Severe or chronic vomiting may also cause hypokalemia in cats. Another cause that may be underdiagnosed in cats is hyperaldosteronism, which is the overproduction of a hormone called aldosterone by adrenal gland tumors. Aldosterone causes potassium loss in the urine. A variety of other diseases can also cause or contribute to hypokalemia (such as hyperthyroidism) but are less common. Hypokalemia is the most common cause of generalized muscle weakness in cats.

How is hypokalemia treated?

Hypokalemia and its associated clinical signs may be quickly corrected by potassium supplementation. In severe cases, potassium may be given intravenously. Supplementation quickly corrects hypokalemia and reverses muscle weakness. Your veterinarian will determine how quickly to correct this deficiency, because if intravenous potassium is given too rapidly, it can cause heart arrhythmias or abnormal heartbeats. In less severe cases, and for long-term maintenance of blood potassium, dietary supplementation is usually necessary.

Potassium gluconate and potassium citrate are oral supplements that are well tolerated by most cats and can be easily added to the diet. It may be necessary to continue supplementing potassium permanently, depending on the cause of hypokalemia. It is usually necessary to intermittently monitor the cat’s treatment response through blood sample analysis to ensure the supplementation is adequate but not excessive. Excessive potassium levels may also cause problems, primarily with the heart.