Myxoedema coma in a dog with a cervical abscess

A 7-year-old, female, neutered Staffordshire bull terrier was referred with a 2-month history of a ventral cervical mass, a recent development of generalised skin swelling and a history of sad facial expression for the last 4 years. Clinical examination revealed generalised non-pitting oedema and depressed mentation. A tentative diagnosis of myxoedema coma was made based on clinical findings and laboratory results. Treatment with oral levothyroxine was administered, and a marked reduction of the non-pitting oedema was observed after 48 hours. Total T4 (<6 nmol/L; reference interval: 10-45) and thyroid-stimulating hormone (0.79 ng/mL; reference interval: 0.00-0.60) levels confirmed hypothyroidism. A migrating foreign body causing a cervical abscess was detected and removed by exploratory surgery. At 2-month follow-up, the clinical signs had resolved and total T4 levels were at the ideal level. This case emphasises the importance of early recognition and treatment of myxoedema in dogs presenting with non-pitting oedema.