Intravenous administration of levothyroxine for treatment of suspected myxedema coma complicated by severe hypothermia in a dog.

A 7-year-old male English Coonhound with suspected myxedema coma complicated by severe hypothermia and metabolic abnormalities was treated with a combination of active external and core rewarming techniques, i.v. and oral administration of levothyroxine, supplemental oxygen, and administration of fluids (0.9% NaCl solution). Myxedema coma develops as a consequence of severe hypothyroidism and is characterized by a hypometabolic, stuporous state. Myxedema coma is associated with a high mortality rate, and most reported cases have involved Doberman Pinschers. Intravenous administration of levothyroxine can be used successfully in combination with oral administration to restore normal metabolic function and assist in warming and thermoregulation, although dosages should be conservative to avoid adverse cardiovascular effects.