Dietary hyperthyroidism in a dog with epileptic seizures

This report discusses a case of suspected dietary hyperthyroidism in a 2-year-old male crossbreed dog. The dog presented with a history of tonic-clonic seizures, seen over the previous 6 months, and was refractory to increasing doses of phenobarbitone. Serum total thyroxine concentrations were persistently elevated on repeated sampling; the rest of the investigations were normal. The initial diet – a raw food diet – was tested and found to contain detectable levels of total thyroxine. Dietary hyperthyroidism was therefore proposed as a potential cause of seizures in this case.