Hyperparathyroidism in Dogs

Hyperparathyroidism describes a pattern in which the parathyroid glands—small structures near the thyroid in the neck—produce too much parathyroid hormone. This hormone normally regulates calcium levels in the blood, and when present in excess, it can pull calcium from bone and raise the amount circulating in the bloodstream. The condition can develop on its own (primary hyperparathyroidism, often linked to a small benign growth on one of the glands) or as a response to another process, such as kidney disease or dietary imbalance (secondary hyperparathyroidism). Owners may notice increased thirst and urination, reduced appetite, occasional vomiting, or a general loss of energy. Some dogs show no outward signs at all, and the pattern is identified only when blood tests reveal elevated calcium during routine screening or investigation of another concern. The signs, when present, tend to develop gradually and can be subtle in the early stages. This page explores what hyperparathyroidism may look like in a living dog, the mechanisms that drive changes in calcium and bone, how the condition is investigated through blood tests and imaging, and the range of approaches used depending on the underlying cause and the degree of disturbance.