Clinical clues to diagnosis include:
- history of hyperthyroidism, most commonly Graves' disease
- new physiologic stress to precipitate thyroid storm
- extreme signs and symptoms of adrenergic hyperactivity
- opthalmopathy (exophthalmos, lid lag) if history of Graves'
- altered mental status
- proximal myopathy
Diagnostic tests:
- low TSH with elevated FT4 or Ft3 is diagnostic
Treatment:
- If clinical suspicion is high, treat immediately
- block synthesis: propylthiouracil (PTU), this is generally favored over methimazole because it also inhibits peripheral conversion of T4 --> T3
- block hormone release: iodine (Lugol's iodine solution). PTU should be given 1 hour prior to this to prevent organification of the iodine. Don''t give to patients with iodine-induced hyperthyroidism. Lithium, which has more side affects and is difficult to dose, can be used as an alternative.
- prevent peripheral hormone conversion: dexamethasone
- block peripheral adrenergic blockade: propranolol
- provide supportive care: acetaminophen, ice packs, cooling blankets, treat underlying precipitant, hydrocortisone for potential relative adrenal insufficiency (if given, can exchange for dexamethasone)
Source
Sternlicht, J. Morgan, J. "Thyroid and Adrenal Disorders." Marx: Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th ed. Mosby. 2006