Feline acromegaly: an underdiagnosed endocrinopathy?

Abstract

BACKGROUND: Feline acromegaly has been reported infrequently in the veterinary literature and current knowledge of this endocrinopathy is based on limited numbers of animals with relatively advanced clinical signs. HYPOTHESIS: This study was undertaken to screen diabetic cats for the presence of acromegaly. ANIMALS: Diabetic cats with variable control examined by general practitioners in the United Kingdom. METHODS: Blood samples were screened for the possible presence of acromegaly with basal serum concentrations of insulin-like growth factor 1 (IGF-1) and, when available, feline growth hormone (fGH). In patients with markedly increased IGF-1 concentrations intracranial computed tomography (CT) was offered, and in selected cats additional imaging was performed. RESULTS: IGF-1 was determined in 184 variably controlled diabetic cats; 59 cats had markedly increased IGF-1 concentrations (>1,000 ng/mL; reference interval, 208-443 ng/mL). Eighteen cats subsequently were examined, and acromegaly was confirmed in 17 cats. Notable findings included absence of a detectable pituitary mass lesion in some affected cats regardless of whether CT or magnetic resonance imaging (MRI) was used. Hypertension was not found to be a complication in the evaluated cats and respiratory stridor was more prevalent than previously reported. CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of IGF-1, growth hormone (GH), or both is useful in the diagnosis of acromegaly in cats.