Hyperthyroidism in Cats

Abstract

This review draws on published research studies to summarize the available evidence about the risk factors for feline hyperthyroidism. Based on the known goitrogens that may be present in the cat's food, drinking water or environment, it proposes measures that cat owners can implement that might prevent, or reduce the prevalence of, thyroid tumors and hyperthyroidism in their cats.

ANIMAL MODELS OF DISEASE: Feline hyperthyroidism: an animal model for toxic nodular goiter

“…Approximately, 2% of hyperthyroid cats develop thyroid carcinoma, which can be classified as either follicular, papillary or mixed (Turrel et al 1988, Hibbert et al 2009). However, the prevalence of malignancy developing within a feline goiter appears to increase progressively over time, especially if the toxic goiter is not definitively treated with thyroidectomy or radioiodine (Peterson 2012, Broome & Peterson 2014, Peterson & Broome 2014a. A similar prevalence of thyroid cancer is also reported in humans with toxic nodular goiter (Sokal 1954, Gandolfi et al 2004, Cerci et al 2007, Khan & Nose 2010.…”

“…Over the last 35 years, the prevalence of thyroidal pathologic abnormalities and the associated state of hyperthyroidism have steadily increased. It is now accepted as the most common endocrine disorder in cats and the most important cause of morbidity in middle-aged cats in the USA, Canada, UK, Europe, Australia, New Zealand, and Japan (Mooney & Peterson 2012, Peterson 2012.…”

“…In three studies in which senior euthyroid cats were screened for thyroid nodules, 38% (Chaitman et al 1999), 59% (Norsworthy et al 2002a), and 76% (Boretti et al 2009) of these cats had a palpable goiter. When these euthyroid nodules were examined histopathologically, 65-85% were confirmed as nodular hyperplasia or adenoma (Norsworthy et al 2002b, Ferguson & Freeman 2006.…”

“…Since first being reported in the USA in the late 1970s (Peterson et al 1979), there has been a dramatic increase in the prevalence of hyperthyroidism in cats, and it has emerged worldwide as one of the most common diseases affecting mature and senior cats (Peterson 2012).…”

“…Spontaneous hyperthyroidism is an extremely common endocrine disorder of middle-to old-aged cats (Mooney & Peterson 2012, Peterson 2013a. Since first being reported in the USA in the late 1970s (Peterson et al 1979), there has been a dramatic increase in the prevalence of hyperthyroidism in cats, and it has emerged worldwide as one of the most common diseases affecting mature and senior cats (Peterson 2012).…”