As a pet science blog author, I’ve always been fascinated by the complex yet delicate balance of hormones in our furry friends. One such hormone is the parathyroid hormone, which, when not in balance, can lead to a condition known as hyperparathyroidism. This condition is not as commonly discussed as others, but it’s essential to understand its implications for our pets’ health.
Introduction to Hyperparathyroidism
Hyperparathyroidism is a condition where the parathyroid glands—located near the thyroid glands in the neck—overproduce parathyroid hormone. This hormone is vital for maintaining the correct balance of calcium and phosphorous in the blood. When blood calcium levels are low, the hormone kicks in, pulling calcium from the bones to restore balance.
Types of Hyperparathyroidism
There are two primary types of hyperparathyroidism that affect our pets:
Primary Hyperparathyroidism
Primary hyperparathyroidism occurs when one or more parathyroid glands become cancerous or start producing an excess of the hormone. This leads to higher than normal calcium levels in the blood. It’s more common in older dogs than in cats. Symptoms include loss of appetite, vomiting, increased thirst and urination, and lethargy. These signs often manifest gradually, and by the time they’re noticeable, significant organ damage may have already occurred.
Treatment typically involves surgical removal of the affected gland, which leads to a sudden drop in parathyroid hormone levels and blood calcium. Post-surgery, pets need to be closely monitored and may require calcium supplements if levels drop too low.
Secondary (Nutritional) Hyperparathyroidism
More common than the primary type, secondary nutritional hyperparathyroidism often affects puppies and kittens fed an all-meat or organ diet, like all liver, or a diet imbalanced in calcium and phosphorous. Meat is high in phosphorous but low in calcium, which is essential for bone health. In this condition, the low calcium intake prompts the parathyroid gland to produce more hormone, leading to calcium being extracted from the bones.
Affected young pets may be reluctant to move, stand with splayed legs, and are prone to fractures due to weakened bones. The treatment revolves around a balanced diet to correct the imbalance and prevent further bone degradation. However, any skeletal deformities that have occurred are usually permanent.
Secondary (Renal) Hyperparathyroidism
In dogs with kidney disease, hyperparathyroidism can be a common complication. As kidney function declines, the body struggles to eliminate phosphorus and produce calcitriol, a hormone that works alongside parathyroid hormone to regulate calcium levels. This imbalance results in excess parathyroid hormone and persistently low calcium levels, potentially causing further damage to the kidneys, bones, and brain.
Treatment for secondary renal hyperparathyroidism focuses on reducing phosphorus levels in the blood. This can be achieved by altering the diet to include lower phosphorus levels and administering phosphate binders, which decrease phosphorus absorption from the intestines. Calcitriol may also be prescribed to help raise calcium levels.
Conclusion
Hyperparathyroidism, while not always at the forefront of pet health discussions, is a critical condition that requires our attention. By understanding the different types and their causes, we can better care for our pets and ensure they live healthy, active lives. As always, a balanced diet and regular veterinary check-ups are key to preventing and managing this condition.
Article by: Veterinary & Aquatic Services Department, Drs. Foster & Smith