INCREASED PARATHYROID-HORMONE CONCENTRATION IN A SIAMESE KITTEN WITH NUTRITIONAL SECONDARY HYPERPARATHYROIDISM

Clinical, biochemical, radiographic, and hormonal evidence of nutritio nal secondary hyperparathyroidism (NSH) in a six-month-old male cat fe d exclusively a meat baby food diet is presented. Nutrient analysis of the baby food revealed an improper calcium:phosphorous ratio for norm al calcium-phosphorous homeostasis. An assay of parathyroid hormone (P TH) and ionized calcium concentrations aided in the diagnosis of NSH w hen compared to concentrations in age- and sex-matched clinically norm al kittens. Data revealed increased PTH concentrations (4 pmol/L) in t he NSH cat when compared to controls (<0.37 pmol/L). Ionized calcium r emained within normal ranges (1.18 to 1.38 mmol/L) when compared to co ntrols pre- and posttreatment, consistent with the known pathogenesis of NSH. Parathyroid hormone concentrations rapidly returned to control levels after correction of dietary imbalances. Clinical and radiograp hic signs resolved.