Feline acromegaly in diabetic cats and its diagnosis

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.