| 英文描述 | Nutritional secondary hyperparathyroidism is most common in horses, where it is called 'big head'. Due to low calcium diets in all species, and grazing of pastures containing oxalates has also caused problems in the horse. Bilateral swelling of the head due to fibrous proliferations extending outward from the original cortices of bones, particularly the maxilla. Dx by dietary history, radiography and necropsy. Fractures may occur. Treat by changing diet. There are reports of hyperparathyroidism in horses due to parathyroid adenoma, and reports of primary hyperparathyroidism with hypercalcemia. Serum calcium levels are usually normal in secondary hyperparathyroidism. |