The parathyroid glands are small endocrine glands located near or within the thyroid glands in the neck. Their primary function is to maintain stable calcium levels in the bloodstream. In dogs affected by PHPT, abnormal growth or dysfunction of these glands leads to continuous hormone secretion, even when calcium levels are already high. This disrupts the normal feedback system that regulates mineral balance in the body.
Clinical signs of PHPT often develop gradually and may initially be subtle. Early symptoms can include increased thirst (polydipsia), increased urination (polyuria), reduced appetite, mild lethargy, or intermittent gastrointestinal issues such as vomiting or constipation. As calcium levels continue to rise, more serious complications may develop, including muscle weakness, tremors, dehydration, and changes in behavior.
The kidneys are particularly affected by prolonged hypercalcemia. Dogs with PHPT may develop calcium-containing kidney stones (nephrolithiasis), urinary tract infections, or progressive kidney dysfunction. In severe cases, untreated PHPT can lead to kidney failure. Additionally, excess calcium can affect the nervous system, resulting in confusion, reduced activity levels, or in rare cases, seizures.
Unlike many inherited eye or neurological disorders, PHPT is most commonly associated with age-related or sporadic glandular changes, such as parathyroid adenomas (benign tumors). However, in some breeds, there may be a genetic predisposition that increases the likelihood of developing the condition, making awareness and screening important in at-risk populations.
The PHPT Health Test may include a combination of diagnostic approaches, such as blood testing and genetic screening where applicable. Blood tests measure calcium and parathyroid hormone levels, helping identify abnormal hormone activity. In some cases, imaging techniques such as ultrasound may be used to evaluate the parathyroid glands. If a known genetic marker is present in a breed, DNA testing may also be performed using a cheek swab or blood sample to assess inherited risk factors.
Results are typically interpreted as:
- Normal / Low Risk: Calcium and PTH levels are within normal range, or no known genetic risk is detected.
- At Risk / Suspicious: Mildly elevated calcium or PTH levels, or presence of genetic predisposition, requiring further monitoring.
- Affected (PHPT): Confirmed abnormal elevation of parathyroid hormone with associated hypercalcemia.
Early detection of PHPT is extremely important because treatment outcomes are significantly better when the condition is identified before severe organ damage occurs. In many cases, surgical removal of the affected parathyroid gland(s) can be curative. Medical management may also be used to control calcium levels before or after treatment.
For breeders, understanding potential hereditary risk factors (where applicable) helps support healthier breeding lines and reduce long-term incidence of endocrine disorders. For dog owners, routine veterinary screening—especially in older dogs—can help detect PHPT early and prevent serious complications such as kidney damage.
The Primary Hyperparathyroidism (PHPT) Health Test is a valuable diagnostic and screening tool that supports early detection, improves clinical outcomes, and promotes long-term metabolic and kidney health in dogs.
