Thyroid storm is decompensated hyperthyroidism (mortality 10 to 30 percent) presenting with hyperthermia (often greater than 39 to 40°C), severe tachycardia or atrial fibrillation, hypertension followed by hypotension, GI symptoms, neurologic changes from agitation to coma. The pharmacologic stack is multimodal and time-sensitive. The classic order: (1) PTU 500 to 1000 mg loading then 250 mg every 4 hours blocks new hormone synthesis and inhibits peripheral T4 to T3 conversion (preferred over methimazole in storm because of the conversion-blocking effect), (2) iodine (SSKI or Lugol) is given 1 hour or more after PTU to block release of pre-formed hormone, never before because iodine alone could fuel synthesis (Jod-Basedow), (3) propranolol IV controls heart rate, blunts adrenergic symptoms (tremor, agitation), and at high doses also decreases T4 to T3 conversion; cardioselective beta-blocker if asthma, (4) hydrocortisone 100 mg IV every 8 hours blocks T4 to T3 conversion and treats relative adrenal insufficiency, (5) supportive care: cooling blanket, acetaminophen (avoid aspirin which displaces T4 from binding proteins and worsens crisis), IV NS, treat precipitant (infection, surgery, missed dose, stress), monitor in ICU. Levothyroxine is the opposite of what is needed.
In-depth explanation
Storm is treated with PTU then iodine then propranolol then hydrocortisone in that order, plus cooling and supportive care. The 1-hour separation between PTU and iodine and the avoidance of aspirin are the two NCLEX-favorite traps.
For study reference only. Always follow current clinical guidelines and your institution’s protocols.