Canine hypoparathyroidism is a relatively uncommon hormonal imbalance in dogs. It results from the end of production of parathyroid hormone (PTH). Hypoparathyroidism appears more common in middle-aged, female dogs. It has no breed predilection1.
What is parathyroid hormone (PTH)?
PTH is manufactured within the dog’s four parathyroid glands. These tiny glands are embedded within the two thyroid glands (two parathyroid glands per thyroid gland). All of these glands are located on the underside of the neck just beneath the skin’s surface.
PTH is in charge of regulating blood calcium and phosphorus levels. It does so by modifying the amounts of calcium and phosphorus absorbed by the gastrointestinal tract, eliminated via the kidneys and released from bones into the bloodstream.
The results of hypoparathyroidism (too little PTH produced by the parathyroid glands) are a decrease in blood calcium and an increase in blood phosphorus levels. The opposite occurs when the parathyroid glands are producing too much PTH (hyperparathyroidism).
Causes of hypoparathyroidism
It is unknown why the parathyroid glands quit producing PTH. Immune-mediated destruction of the parathyroid glands (the immune system attacks the body’s own tissues) is suspected. Surgical removal of the thyroid glands for treatment of thyroid cancer and trauma to the neck region are other potential causes of hypoparathyroidism.
Symptoms of hypoparathyroidism
The symptoms associated with hypoparathyroidism are the result of the abnormally low blood calcium level. The symptoms can be intermittent, particularly early on in the course of the disease. The most common symptoms include: