Iatrogenic hyperthyroidism associated with hypocobalaminaemia in a dog

ABSTRACT

Hypocobalaminaemia in veterinary species has been primarily associated with gastrointestinal disease, and minimal research has investigated other causes. Recent research has suggested that extra‐gastrointestinal factors may also affect cobalamin concentrations. This is supported by transient hypocobalaminaemia seen in dogs undergoing routine orthopaedic surgeries (e.g., tibial plateau levelling osteotomy). Additionally, a feline study identified an association between hyperthyroidism and the development of hypocobalaminaemia, with cobalamin levels normalising once the thyroid hormones are stabilised. The relationship between thyroid hormone and cobalamin has not been researched in other species, including dogs. This case report describes a dog with iatrogenic hyperthyroidism and concurrent hypocobalaminaemia. Baseline cobalamin was not available for comparison. After normalisation of the thyroid hormones, the cobalamin values increased into the normal range. This finding suggests that the relationship between thyroid hormones and cobalamin levels may extend beyond feline patients, and further investigation is warranted in other veterinary species.