Low blood potassium is a medical condition commonly referred to by veterinarians as hypokalemia. It occurs when the levels of potassium in the cat’s blood drop below an acceptable level. Potassium is a necessary electrolyte found in the blood that is required for the normal function of muscles and bodily systems. Hypokalemia can occur in cats that are sick or suffering from fluid loss due to vomiting or diarrhea. In mild to moderate cases that are related to other illnesses, low blood potassium may not be a concern. In moderate or more severe cases, low blood potassium results in extreme muscle weakness and can make walking or holding up the weight of the head difficult. When hypokalemia presents in more severe cases, it has the potential to cause muscle paralysis, which can affect the lungs and heart. Its potential to disrupt proper respiratory and cardiac function can be life-threatening and requires immediate medical attention. 

A cat with low blood potassium may not present any symptoms unless the potassium levels are extremely low or the condition has been ongoing for a prolonged period. The most common symptoms associated with low levels of potassium are weakness and an inability to hold the head up, resulting in a drooped head or irregularly bent neck. Depending on the underlying cause of the decrease in potassium, other symptoms may be observed. 

Symptoms include:

Loss of blood potassium most commonly occurs from one of three presentations. Either the cat has increased excretion of potassium, suffers from inadequate intake, or potassium is being redistributed within their body. These presentations can be a result of a variety of causes. Common causes of low blood potassium in cats include:

Your veterinarian will determine if the cat’s blood potassium levels are within normal range by drawing blood and using standard laboratory testing methods. Your pet’s blood sample will be analyzed for a complete blood count, biochemistry panel, and electrolyte panel. In conjunction with the blood test, your veterinarian will require a complete medical history of your cat and information on any symptoms you have observed or conditions that might have affected the animal’s electrolyte balance. Be prepared to discuss any medications, medical treatments, and the cat’s regular diet. A routine physical examination will also likely be conducted. If your pet’s blood potassium levels are determined to be low, additional testing may be needed to determine the underlying cause of the condition, unless the cause is an obvious one. Urine or fecal samples may be analyzed. Veterinary staff may also use x-rays or other imaging techniques to determine the cause of your pet’s electrolyte imbalance. 

Treatment methods may vary depending on the underlying cause of low potassium in the blood. In severe cases, hospitalization will be required while your pet is being treated. Hospitalization may be prolonged as it is important for your pet to be supported until muscle weakness is no longer a problem. This is due to the potential for respiratory or cardiac failure. Some treatment methods that are commonly used for low blood potassium include:

The primary goal of treatment for low blood potassium is to restore the potassium levels to a normal range. This is generally accomplished with supplementation. If your pet is well enough, oral supplements will be provided. Intravenous supplementation may be required in some cases. Your cat will require monitoring of blood potassium levels during the initial supplementation phase. The use of potassium supplements could be temporary but may require use on a long-term or permanent basis depending on the underlying cause of the condition. They are generally administered in smaller doses to lower the risk of cardiac disruption. More rapid delivery may be deemed necessary if your cat’s condition is poor. Close monitoring of levels will also mitigate the associated risk. 

Oxygen may be provided using tubing, a mask, or an oxygen cage. This is an important treatment for cats that are experiencing difficulty breathing. Oxygen therapy will be provided during hospitalization or while visiting the veterinarian. It carries a very low risk of side effects. 

This treatment will only be prescribed if dehydration is an issue or intravenous potassium supplementation is required. Although IV fluids are considered a common and relatively low-risk treatment, the use of fluids that do not contain potassium could potentially worsen the condition. This treatment method is generally only used while the animal is hospitalized. 

Your cat’s prognosis will depend greatly on the underlying condition that resulted in low blood potassium. With potassium supplementation, levels are usually restored to normal ranges fairly easily. In most cases, the cat’s condition will improve rapidly once potassium levels in the blood are restored. Continued supplementation may be required, however. Be sure to follow all your veterinarian’s instructions while your pet is recovering, including proper dosing of any medications and returning for requested follow-up visits. If long-term potassium supplementation is required, ensure you only use the prescribed amount and continue to monitor your cat closely for signs of low or high potassium levels. Your pet may require continued follow-up visits for a prolonged period in these cases.