Posted on April 10, 2016
Hypoparathyroidism is a hormonal imbalance in dogs that results from the cessation of production of parathyroid hormone (PTH). Hypoparathyroidism is more common in middle-aged female dogs, and it has no breed predilection.
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 just beneath the skin surface on the underside of the neck.
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.
Hypoparathyroidism (too little PTH produced by the parathyroid glands) causes decreased calcium and increased phosphorus levels within the blood stream. The opposite occurs when the parathyroid glands are producing too much PTH (hyperparathyroidism).
It is unknown why the parathyroid glands quit producing PTH. Autoimmune 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.
The symptoms associated with hypoparathyroidism result from the abnormally low blood calcium level. The symptoms can be intermittent, particularly early on in the course of the disease, and most commonly include:
- Muscle tremors or twitching
- Stiff gait
- Uncoordinated gait
- Anxious, restless behavior
- Increased panting
- Loss of appetite
The testing typically performed to arrive at a diagnosis of hypoparathyroidism typically includes:
- Complete blood cell count
- Blood chemistry profile (includes calcium and phosphorus measurements)
- Ionized calcium measurement (the active form of calcium within the bloodstream) molecule
- PTH measurement
Therapy for hypoparathyroidism consists of administration of vitamin D and calcium. Vitamin D supplementation is necessary to assist with the absorption of dietary calcium from the gastrointestinal tract.
Treatment with intravenous fluids and calcium is warranted for dogs with severe symptoms. For dogs who are in stable condition, the calcium and vitamin D can be administered orally at home. Both are given daily (may be multiple times daily) and the dosages are adjusted based on the dog’s symptoms as well as follow-up blood calcium and phosphorus levels. Many successfully treated dogs can be weaned off of the calcium supplement as long as vitamin D therapy is continued. As is the case with most canine hormonal imbalances, lifelong treatment and monitoring are required.
Hypoparathyroidism is considered to be a very treatable disease with an excellent prognosis as long as conscientious treatment and monitoring are available.
Have you had a dog who required treatment for hypoparathyroidism?
Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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