Prevalence, clinical and epidemiological features of feline hyperthyroidism at a veterinary teaching hospital in Brazil: a retrospective study

Abstract

The hyperthyroidism is the most frequently endocrinopathy in cats. The increasing number of diagnoses over time is due to the greater familiarity with the disease and the development of increasingly sensitive diagnostic tools available. This study aimed to retrospectively evaluate the prevalence, clinical characteristics and risk factors of hyperthyroidism in cats admitted at one of the largest veterinary teaching hospital in Brazil. Between 2002 and 2007, 234 cats were admitted to the veterinary teaching hospital of the University of São Paulo, Brazil. Total thyroxine (T4t) serum concentration was measured from all cats. Also analyzed the medical charts of cats. Of the 234 cats, 26 (11.1%) were considered hyperthyroid (T4t ≥3.8 µg/dL). Of these 26 cats, only two (7.7%) were initially diagnosed as hyperthyroid. The age of cats ranged from 6 to 27 years old (13.1 ± 4.5 years). Twelve patients (46.2%) were female and 14 (53.8%) were male. Eight (30.8%) cats were Siamese, while the others were mixed breed (69.2%). Dry food was the most common food type consumed by cats. There was a high prevalence of hyperthyroid cats with concomitant chronic kidney disease (CKD). This study sheds light on the importance of routinely monitoring feline hyperthyroidism and brings epidemiological and clinical data of this endocrinopathy in cats from one of the largest veterinary teaching hospitals in the country.