Canine Parathyroid Diseases

Canine parathyroid diseases affect dogs of all sizes, ages and breeds.puppy image by Lisa Eastman from Fotolia.com

Dogs have a total of four parathyroid glands, two on each side of the actual thyroid. While the glands are next to the thyroid, they actually have little to nothing in common with the thyroid gland. The main function of the parathyroid glands is to maintain calcium homeostasis. This means the parathyroid glands control normal calcium concentrations and function (homeostasis, which means "still" and "similar" in Greek, refers to the ability to regulate and maintain.) There are parathyroid diseases that affect canines.

Primary Hyperparathyroidism

With normal parathyroid function, the glands' secretion ebbs and flows. The secretion decreases when needed to allow the calcium concentration to return to normal when levels have become too high. In the case of primary hyperparathyroidism, the glands keep secreting even though the levels may be too high, because there is no regulation. In this case, the disease is called primary hyperparathyroidism and almost always leads to hypercalcemia, which can be fatal.

Hypercalcemia, a parathyroid disease found in dogs, can be caused by a few varying suspects: lymphoma, sac carcinoma, mammary gland tumors, parathyroid gland tumor, kidney failure, Vitamin D poisoning and Addison's disease. In cases where the hypercalcemia is caused by a parathyroid gland tumor, the tumor is secreting too much of the parathyroid hormone, causing increased levels of calcium, thus leading to hypercalcemia.

Another canine parathyroid disease is the presence of a malignant parathyroid carcinoma in one of the glands. According to Dr. Richard E. Goldstein, a malignant parathyroid carcinoma is pretty rare in dogs and usually seen in older dogs, above the age of ten years. Symptoms that a dog may have this parathyroid disease might be increased drinking and urination, fatigue, lethargy and weakness.