Hepatic Failure/GI/Endocrine Emergencies

Criteria

Points

Precipitant history

• Positive

• Negative

Score

• > 44: Thyroid storm

• 25–44: Suggestive/impending storm

• < 25: Storm unlikely

Information from: Bahn RS, Burch HB, Cooper DS, et al. Hyperthyroidism and other causes of

thyrotoxicosis: management guidelines of the American Thyroid Association and American Association

of Clinical Endocrinologists. Thyroid 2011;21:593-646.

Thyroid crisis can develop in patients with a history of untreated hyperthyroidism but is more often

precipitated by an acute event. Precipitating events include surgery, pregnancy, and trauma. In

hospitalized patients, the most common cause is infection.

Drugs associated with thyroid crisis include radioactive iodine, overdose of levothyroxine

or liothyronine, cytotoxic chemotherapy, aspirin, iodinated contrast dye, amiodarone, and

organophosphate toxicity.

Rarely, thyroid crisis is the initial presentation for patients with undiagnosed hyperthyroidism.

Management

Treatment of thyroid crisis is complex and requires several interventions simultaneously.

Decrease thyroid hormone synthesis.

Methimazole and propylthiouracil inhibit production of new thyroid hormone.

ii.

Propylthiouracil is preferred in thyroid crisis because it not only blocks new thyroid synthesis

but also decreases peripheral conversion of T4 to T3.

iii.

Propylthiouracil is also preferred in the first trimester of pregnancy; after the start of the second

trimester, patients may continue propylthiouracil or transition to methimazole. Concentrations

of both agents in breast milk are low, but methimazole is generally preferred in breastfeeding

mothers due to risk of hepatotoxicity with propylthiouracil.

iv.

Propylthiouracil is given as a 500- to 1000-mg loading dose, followed by 250 mg every 6

hours. Doses may be given enterally or rectally.

Patients receiving propylthiouracil should be monitored for adverse effects, including

agranulocytosis, allergic hepatitis, and vasculitis.

vi.

If methimazole is used because of propylthiouracil allergy or intolerance, usual dose is 20–30

mg every 8 hours. Doses may be given enterally or rectally.

vii.

Intravenous steroids (hydrocortisone 300-mg loading dose, followed by 100 mg every 8 hours)

should be initiated to block the conversion of T4 to T3.

viii.

Plasmapheresis has been used to remove cytokines, antibodies, and thyroid hormones from

plasma when traditional therapies have not been successful. Effects are transient, lasting 24–

48 hours, but improvement in clinical status has enabled patients to be stabilized for definitive

therapy with thyroidectomy.

Inhibit thyroid hormone release with inorganic iodine.

Propylthiouracil and methimazole inhibit thyroid hormone synthesis but do not block release

of stored hormone from the thyroid gland.

ii.

Initial dose of iodine should be given at least 1 hour after the first dose of propylthiouracil or

methimazole to reduce the risk of providing more substrate for thyroid hormone production.

iii.

Oral potassium iodide (Lugol solution) is administered as 3–5 drops every 6 hours. If available,

sodium iodide can be given as an intravenous infusion of 0.5–1 g over 24 hours.