Hyperthyroidism

Question 1

Pathomechanism and Diseases associated with Hyperthyroidism

Answer 1

Patho:
■ Graves disease (anti-TSH-R Ab) = ⅔ cases
■ Toxic multinodular goiter: 2nd most common.
● Process: Peroid of Iodine Deficiency= Decreased T4= Thyroid cell hyperplasia = Multinodular Goiter= Increaseed risk of TSH receptor mutation that becomes constitutively active= Eventually excessive production of T3, T4

■ Toxic adenoma: solitary T4 producing adenoma, “hot nodule”
■ Exogenous: iodine excess (food contamination, contrast media) can
cause thyroid storm if already hyperthyroid

Question 2

Symptoms of Hyperthyroidism

Answer 2

Irritability, tremor, diarrhea, weight loss, increased apettite, sweating, dyspnea, palpitations, hypertension, tachycardia, oligomenorrhea, infertility.

■ Grave’s: also has exophthalmos and pretibial myxedema

Question 3

Complications of Hyperthyroidism :

Answer 3

■ Arrhythmia (especially atrial fibrillation), high-output heart failure
■ Thyroid storm: significant worsening of preexisting hyperthyroidism
(e.g. in infection, thyroid trauma during surgery). May be fatal.
● Causes agitation, delirium, fever, diarrhea, coma, tachyarrhythmia.

Question 4

Diagnosis of Hyperthyroidism :

Answer 4

Usually T3/T4 high, TSH low
■ Graves: anti-TSHR Ab
■ Scintigraphy: hot nodules in toxic adenoma, can visualize toxic
multinodular goiter. Graves will be generalized as “warm.”

Question 5

Treatment of Hyperthyroidism

Answer 5

Symptom control: propranolol
■ Block T4 synthesis: propylthiouracil and methimazole
● Both have risk of agranulocytosis. Methimazole is teratogenic, PTU is
more hepatotoxic.
■ Radioiodine uptake to destroy gland
■ Thyroidectomy/&$)$,::H&-.-,:6&’()*&.+&!B1&(8K$’H&,8#&0&WDL&
■ Tx of Thyroid storm: ß blockers, PTU, corticosteroids, potassium
iodide (4 P’s: propranolol, PTU, prednisolone, potassium iodide)