Primary hyperparathyroidism caused by a functional parathyroid adenoma in a horse.

The research discusses a case of primary hyperparathyroidism caused by a functional parathyroid adenoma in a 14-year-old Arabian gelding. The condition was identified through various tests after the horse presented with weight loss and anorexia, and is suggested as a potential cause of hypercalcemia in horses when other common causes have been eliminated.

Case Presentation and Diagnosis

• The horse, a 14-year-old Arabian gelding, was presented with symptoms of weight loss and anorexia spanning three weeks.
• Repeated laboratory tests indicated continued hypercalcemia (excess of calcium in the blood), and the horse’s serum phosphorus concentration was found to be within or less than the standard range.
• A high concentration of the parathyroid hormone was also detected in the horse’s blood.
• Following the horse’s death, histologic examination (study of tissue under a microscope)of specimens obtained at necropsy (animal autopsy) revealed a parathyroid adenoma (a benign tumor arisen from the parathyroid gland).
• Based on these findings, the clinicians diagnosed the condition as primary hyperparathyroidism caused by a functional parathyroid adenoma.

Condition Comparisons and Recommendations

• The abnormalities observed in the horse’s calcium and phosphorus concentrations were consistent with those seen in primary hyperparathyroidism in dogs, where this syndrome has been well studied.
• The study concludes that primary hyperparathyroidism should be considered as a potential source of hypercalcemia in horses after ruling out other common causes such as humoral hypercalcemia of malignancy (HHM), nutritional secondary hyperparathyroidism, chronic renal failure, vitamin D toxicosis, and bony or granulomatous disease.