Your dog's parathyroid glands, residing near or on the thyroid glands, regulate the amount of phosphorous and calcium in his blood. Parathyroid disease results when too much or too little of the hormone produced by the glands are in circulation. A diagnosis of hyperparathyroidism indicates overproduction of parathyroid hormone, while hypoparathyroidism occurs when the amounts are insufficient.
Dogs suffering from hypoparathyroidism don't have enough calcium in their blood. While any dog can develop hypoparathyroidism, the most affected breeds include standard and miniature poodles, German shepherds, Labrador retrievers, miniature schnauzers and terriers in general. Symptoms include seizures, difficulty walking, fever, face rubbing, appetite loss, excessive drinking and peeing, vomiting, muscle twitching and cataracts. Your vet diagnoses the condition by testing your dog's blood and urine.
Severely affected dogs might require hospitalization to treat symptoms or bring calcium levels back within an acceptable range. Your vet will prescribe calcium supplements, which you might have to give your dog for the rest of his life. Your vet will monitor your dog regularly, checking to see if his calcium levels are adequate. Your vet changes the calcium supplement dosage based on your dog's needs. Don't give your dog over-the-counter calcium or vitamin D supplements without your vet's approval.
Overproduction of parathyroid hormone is much less common than underproduction. The most affected breed is the Keeshond, whose rate of hyperparathyroidism is approximately 50 times that of other breeds. The condition generally occurs because a benign tumor develops on the gland. Less often, the tumor is malignant. Hyperparathyroidism results in hypercalcemia, or too much calcium in the blood. Symptoms include excessive drinking and urinating, appetite loss, stiffness, vomiting and lethargy. Your vet makes a diagnosis via blood tests and an ultrasound to determine if there are growths on the glands.
Unfortunately, there's no simple cure for hyperparathyroidism. Dogs diagnosed with the condition require surgery to remove one or more of the four parathyroid glands. One remaining gland is sufficient for phosphorous and calcium regulation. An alternative treatment, not available at the majority of veterinary hospitals, involves using ultrasound and an injection of alcohol or heat to eliminate cells producing too much hormone. If you can bring your dog to a veterinary hospital providing this service, you can avoid surgery.