Primary hypoparathyroidism in a cat complicated by suspect iatrogenic calcinosis cutis

An adult male cat presented to the Ontario Veterinary College after having a seizure at the humane society. The cat was diagnosed with primary hypoparathyroidism and was treated with calcium and vitamin D3 supplementation. Calcium supplementation included subcutaneous (SC) administration of diluted calcium gluconate according to protocols described in recent literature. Seven days after SC calcium administration, firm SC masses developed in the intrascapular area where the injections were given and in the dependent axillary area. These areas became raised, formed crusts, necrosed, and left scars. Although not histopathologically confirmed, the author postulates that this was a direct reaction to SC calcium gluconate administration.