Primary hyperparathyroidism in cats: seven cases (1984-1989).

The medical records of 7 hypercalcemic cats with primary hyperparathyroidism were evaluated. Mean age was 12.9 years, with ages ranging from 8 to 15 years; 5 were female; 5 were Siamese, and 2 were of mixed breed. The most common clinical signs detected by owners were anorexia and lethargy. A cervical mass was palpable in 4 cats. Serum calcium concentrations were 11.1 to 22.8 mg/dl, with a mean of 15.8 mg/dl calculated from each cat's highest preoperative value. The serum phosphorus concentration was low in 2 cats, within reference limits in 4, and slightly high in 1 cat. The BUN concentration was greater than 60 mg/dl in 2 cats, 31 to 35 mg/dl in 2 cats, and less than 30 mg/dl in 3 cats. Abnormalities were detected in serum alanine transaminase, aspartate transaminase, and alkaline phosphatase activities from 2 or 3 cats. Parathormone (PTH) concentrations were measured in 2 cats before and after surgery. The preoperative PTH concentration was within reference limits in 1 cat and was high in 1 cat. The PTH concentrations were lower after surgery in both cats tested. A solitary parathyroid adenoma was surgically removed from 5 cats, bilateral parathyroid cystadenomas were surgically resected in 1 cat, and a parathyroid carcinoma was diagnosed at necropsy in 1 cat. None of the cats had clinical problems with hypocalcemia after surgery, although 2 cats developed hypocalcemia without tetany, one of which was controlled with oral administration of dihydrotachysterol and the other with oral administration of 1,25 dihydroxyvitamin D. All 5 of the cta that underwent removal of an adenoma were alive at least 240 days after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)