Morning Report: Thyroid Storm

Thyrotoxicosis: Hypermetabolic syndrome secondary to excess synthesis and secretion of thyroid hormones. Most common forms of hyperthyroidism being Graves disease, toxic multinodular goiter, and toxic adenoma.

Common Signs & Symptoms:
-Nervousness; anxiety; increased perspiration; heat intolerance; hyperactivity; palpitations.
-Tachycardia or atrial arrhythmia; hand tremors; hypertension; lid lag; weight loss.

Workup:
↓ TSH; ↑ thyroid hormones – thyrotoxicosis
↓ TSH; nml thyroid hormones – subclinical hyperthyroidism

(auto-antibody studies and scintigraphy beyond our scope)

Thyroid Storm AKA Thyrotoxic crisis: acute and life-threatening hyper metabolic state marked by fever, tachycardia, hypertension, neurologic and GI abnormalities.

Estimated mortality rates of about 90% if left untreated. With early management adult mortality rates have declined to less than 20%.

Burch Watorfsky score. See table 1.

Treatment:

B-blockers: Propranalol: 1mg IV q 15 min (max 5mg). 20-120 mg PO q6-8 hrs when symptoms resolved.

Antithyroid Meds: Methimazole and Propylthiouracil.

They inhibit the formation and coupling of iodotyrosines in thyroglobulin, which is necessary for thyroid hormone synthesis, thus reducing hormone levels.

Methimazole is more potent with longer duration of action, taken once daily, as opposed to PTU which is 2-3 times daily. Better compliance.

PTU is drug of choice in thyroid storm as it also inhibits conversion of T4 to T3. Otherwise it is second line, and reserved for use in pregnant patients or those allergic/intolerant to methimazole.

Iodine: Sodium Iodide 1g IV q8-12 hours. Blocks conversion of T4 to T3 and the release of thyroid hormone. Used usually for thyroid storm. Give an hour after anti- thyroid medications to prevent its use in thyroid hormone synthesis.

Glucocorticoids: Hydrocortisone 100mg IV q8. Decreases peripheral conversion of t4 to t3.

Adverse reactions: Include agranulocytosis, aplastic anemia, hepatitis. 2010 FDA added a boxed warning for PTU for severe liver injury and acute liver failure.

Burch Watorfsky Score