Hypocalcaemia in Cats
What is hypocalcaemia?
Hypocalcaemia is a term that refers to low blood concentrations of calcium. Calcium is an important electrolyte (chemical) within the body, and is needed for normal function of muscles and nerves. Calcium concentrations in the blood are usually controlled very closely but occasionally, this control is lost and may result in low blood concentrations (hypocalcaemia).
What are the clinical signs of hypocalcaemia?
Mild decreases in blood calcium concentrations will not usually cause any clinical signs but may be detected on blood testing. However, if moderate to severe hypocalcaemia develops, then clinical signs may occur.
Early signs of hypocalcaemia include restlessness, stiffness, weakness, irritability, muscle tremors and hypersensitivity (exaggerated responsiveness) to touch and sound. More profound signs include severe generalised muscle twitching, leading on to uncontrolled muscle spasms, seizures and ultimately death.
What causes hypocalcaemia?
The most common cause of hypocalcaemia in cats is a post-operative complication following surgical treatment for hyperthyroidism (a common condition in older cats). Because of this risk, cats are usually kept hospitalised for around 3 days following this type of surgery so that blood calcium concentrations can be monitored, and treatment given if necessary. Other less common causes of hypocalcaemia may also occur, including hypocalcaemia associated with lactation in a nursing queen, and hypocalcaemia assoicated with renal failure when phosphate levels are very high.
Low circulating albumin can also cause hypocalcaemia. This is usually without symptoms (asymptomatic) provided the free calcium is unaffected. In some conditions where low blood albumin (hypoalbuminaemia) is due to actual albumin loss as occurs in certain kidney diseases (nephrotic syndrome) and bowel problems (protein losing enteropathy) a symptomatic hypocalcaemia may be evident.
How is hypocalcaemia treated?
In cases of severe hypocalcaemia with marked clinical signs, immediate correction of the problem will be necessary through the use of calcium injections. Most cats will need to be hospitalised until calcium concentrations are stable, as this is a potentially life-threatening condition.
Long-term treatment of hypocalcaemia may include supplementing the diet with calcium salts, and administration of vitamin D (tablets, capsules or liquid), which is used to increase the absorption of calcium from the intestinal tract. Regular monitoring of blood calcium concentrations will be needed by your veterinary surgeon to ensure successful treatment, and the duration of treatment depends on the underlying cause of the condition.
© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license. This content written by LifeLearn Animal Health (LifeLearn Inc.) is licensed to this practice for the personal use of our clients. Any copying, printing or further distribution is prohibited without the express written consent of LifeLearn. This content does not contain all available information for any referenced medications and has not been reviewed by the FDA Center for Veterinary Medicine, or Health Canada Veterinary Drugs Directorate. This content may help answer commonly asked questions, but is not a substitute for medical advice, or a proper consultation and/or clinical examination of your pet by a veterinarian. Please contact your veterinarian if you have any questions or concerns about your pet’s health. Last updated on Feb 6, 2017.
