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Case In Point: Hyperthyroidism: 5 Cases to Hone Your Diagnostic Skills

Case In Point: Hyperthyroidism: 5 Cases to Hone Your Diagnostic Skills

Weight Loss and Anxiety in a Young Woman
1. A 32-year-old woman presents with weight loss of 6.4 kg (14 lb) during the past 8 months and diarrhea of recent
onset. Menstruation had ceased 10 weeks earlier. She appears anxious, with pressured speech. Physical examination detects
baseline sinus tachycardia, sweaty palms, and a diffusely enlarged thyroid gland. Laboratory tests reveal a thyroid-stimulating
hormone (TSH) level of 0.00 μU/mL (normal, 0.45 to 4.5 μU/mL), a free thyroxine (FT4) level of 4.8 ng/dL (normal,
0.61 to 1.76 ng/dL), and a positive thyroid-stimulating immunoglobulin (TSI) level with high titer.

This is a classic presentation of hyperthyroidism caused by Graves' disease. The diagnosis can be made based
on clinical presentation, physical examination, and selected laboratory tests. Further evaluation with a radioactive iodine
(RAI) uptake and thyroid scan would reveal an enlarged gland with increased uptake and confirm the diagnosis.
The tests would also yield necessary dosing information if the patient were to be treated with RAI ablation. Alternatively,
she could be treated with antithyroid medications or surgery. Subsequent to surgery, thyroid hormone replacement
therapy with levothyroxine would be needed.
If this patient were pregnant, treatment options would change. RAI ablation would now be contraindicated, and
the patient could be offered antithyroid treatment with propylthiouracil (PTU). Following pregnancy, RAI ablation
with subsequent thyroid replacement therapy would be recommended.

An Elderly Man With Recent Atrial Fibrillation
2. A 76-year-old man with known heart disease is admitted to the hospital because of new onset of shortness of breath,
fatigue, and atrial fibrillation. He denies weight loss, nervousness, and insomnia. There is no evidence of an acute myocardial
infarction or pulmonary embolus. On physical examination, his heart rate is 136 beats per minute; beats are irregularly
irregular; and fine rales are heard at both lung bases. His blood pressure is 152/82 mm Hg, without orthostatic
changes. Results of laboratory tests indicate a hemoglobin level of 14.6 g/dL, a TSH level of 0.02 μU/mL (normal, 0.45
to 4.5 μU/mL), and an FT4 level of 3.3 ng/dL (normal, 0.61 to 1.76 ng/dL).

An elderly patient with hyperthyroidism secondary to Graves' disease, toxic multinodular goiter, or toxic adenoma
often presents without classic symptoms. A diagnosis of Graves' disease is confirmed by measurement of TSI
and an RAI uptake and thyroid scan. Imminent treatment includes βblockers (and corticosteroids, if necessary) to
control the hyperthyroid state, which is now causing secondary atrial fibrillation and congestive heart failure.
βBlockers will control the tachycardia and reduce the risk of heart failure; corticosteroids will block the peripheral
conversion of T4 to triiodothyronine (T3). PTU might be useful for inhibiting intrathyroidal hormone production (oxidation
and organification) and the peripheral conversion of T4 to the metabolically active T3. Plans should be made
for RAI ablation, followed by thyroid hormone replacement therapy. In cases such as this, the atrial fibrillation is
usually not converted to a normal sinus rhythm until the hyperthyroid state is successfully treated. Anticoagulation
therapy should be considered as well.

Nodule in a Woman With Insomnia
3.A 29-year-old woman presents for her yearly pelvic examination and Pap smear. She complains of insomnia and
nervousness. Physical examination reveals an enlargement of the left lobe of the thyroid gland, which suggests the presence
of a nodule. Laboratory test results reveal a TSH level of 0.02 μU/mL (normal, 0.45 to 4.5 μU/mL) and an FT4 level of
2.3 ng/dL (normal, 0.61 to 1.76 ng/dL).

To confirm a diagnosis of hyperthyroidism secondary to toxic adenoma. in a patient with abnormal levels of TSH
and FT4, fine-needle aspiration and biopsy (FNAB) of the nodule are indicated. An RAI uptake and thyroid scan can
be used to investigate the possibility of "other" adenomas and to help determine the dosage of 131I for subsequent radioiodine
therapy. Many physicians turn to ultrasonography, but the initial evaluation that consists of TSH and FT4
measurement and FNAB is sufficient for diagnosis. Ultrasonography cannot distinguish benign from malignant
tissue.

Treatment is either surgery (partial thyroidectomy) or RAI ablation. If the nodule persists following treatment
with RAI ablation, a second tissue biopsy is indicated.

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