The Dept of Anaesthesia & Intensive Care, CUHK
- terminal state of decompensated hypothyroidism
- hypothermia, sometimes due to CNS depressants (eg phenothiazines,
- obscure, but hypothermia, respiratory acidosis and hyponatraemia with inappropriate ADH may all play a part.
- hypothermia with absence of shivering. May be profound
- hypotension: commonly accompanied by bradycardia. Baroreceptor dysfunction,
and reduction in plasma volume contribute. Small heart suggests adrenal
- hypoventilation: very frequent. Contributing factors include: decreased responsiveness to hypoxia and hypercarbia, respiratory muscle fatigue, obesity, thickening of vocal cords, drugs
GI & GU
- paralytic ileus, megacolon and urinary retention frequent
- coma: due to combination of hypothermia, hypercarbia, hypoxia, cerebral
oedema and other metabolic derangements.
- drugs (eg phenytoin, frusemide, NSAIDs, steroids, dopamine) can affect
thyroid hormone concentrations and thus mimic biochemical hypothyroidism
- monitor in ICU
- 200-300 mg hydrocortisone per day. Patients with myxoedema coma may have
impaired glucocorticoid response to stress or even frank co-existent adrenal
insufficiency (Schmidt's syndrome; may be masked by hypothyroidism). (Synacthen
test not valid in hypothyroid patients).
© Charles Gomersall December 1999
April, 2014 unless
otherwise stated. The author, editor and The Chinese University of Hong Kong
take no responsibility for any adverse event resulting from the use of this