Hyperthyroidism

HYPERTHYROIDISM 72A

A 25-year-old African American woman presents with a complaint of rapid weight loss despite a voracious appetite. Physical examination reveals tachycardia (pulse rate, 110 beats/min at rest), fine moist skin, symmetrically enlarged thyroid, mild bilateral quadriceps muscle weakness, and fine tremor.

What are the salient features of this patient’s problem? How do you think through her problem?

Salient features: Weight loss with increased appetite; tachycardia; moist skin; enlarged thyroid; muscle weakness; tremor

How to think through: Weight loss, weakness, and tachycardia indicate a systemic process. To avoid anchoring prematurely to thyroid disease as an explanation, what are the other major disease categories that could cause these findings? (Infection, malignancy, connective tissue diseases, vasculitis, medication toxicity.) What other symptoms of hyperthyroidism could you elicit to help confirm your suspicion? (Heat intolerance, restlessness, diarrhea, sleep disturbance, irregular menses.) What additional physical examination signs should be sought when considering hyperthyroidism? (Eyelid lag, exophthalmos, hyperdefecation, abnormally rapid relaxation phase to deep reflexes, pretibial myxedema.) In this case, examination of the thyroid gland shows asymmetry. What common etiologies of hyperthyroidism might present with an asymmetrical exam? (Toxic adenoma, toxic multinodular goiter.) What common etiologies are more likely to present as symmetrical processes? (Graves disease, viral thyroiditis, early autoimmune thyroid disease [“hashimotoxicosis”], thyroid-stimulating hormone [TSH]–producing pituitary adenoma.) How should her thyroid function be evaluated? (Serum TSH alone is the most sensitive initial test.) If the TSH suppressed, what would be the next diagnostic steps? (Serum triiodothyronine [T₃], thyroxine [T₄], thyroid-stimulating immunoglobulins; thyroid ultrasonography, and possibly a radioactive iodine scan; ophthalmology evaluation.) If the TSH in this patient is found to be suppressed, how should she be treated while awaiting the subsequent studies? (The nonspecific β-blocker propranolol is used to control tachycardia and to improve anxiety.) What are the complications of untreated hyperthyroidism? (Heart failure, osteoporosis, risk of thyroid storm.) What are the features of thyroid storm? (Fever, delirium, vomiting, diarrhea, tachycardia, heart failure.)