Cat - Hypocalcaemia

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 (fits) 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 often 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 also occur, including hypocalcaemia associated with lactation (milk production) in a nursing queen.

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.