Hyperthyroidism: Multiple possibilities in the female patient

Hyperthyroidism is a clinical syndrome characterized by an excess of thyroi d hormone, and its clinical consequences. A suppressed serum TSH concentrat ion is the earliest biochemical manifestation of hyperthyroidism. Subclinic al hyperthyroidism, characterized by suppressed serum TSH concentration alo ne, has important clinical consequences. These include bone loss in postmen opausal women and atrial fibrillation. A twenty-four hour radioiodine uptake and radionuclide scan are indispensab le in the differential diagnosis of hyperthyroidism. Graves' Disease, an au toimmune disorder, demonstrates a strong female prevalence; the twenty-four hour radioiodine uptake is normal or elevated. Therapeutic options, includ ing anti-thyroid drugs, radioactive iodine (I-131) and surgery are utilized in all age groups. These include use in women during the reproductive year s. Toxic nodular goiter and "hot" nodules are less common forms of hyperthy roidism; these too have normal or elevated radioiodine uptake, with charact eristic radionuclide scans. Hyperthyroidism with a near-zero radioiodine uptake also has important clin ical implications. Factitious (exogenous) hyperthyroidism is characterized by a low serum thyroglobulin concentration. Treatment consists of decreasin g the dosage of, or withdrawing, thyroid hormone. Painful subacute thyroidi tis, a post-vital syndrome, causes spontaneously resolving hyperthyroidism, which is often followed by hypothyroidism. The most common cause of hypert hyroidism with a low radioiodine uptake is painless, lymphocytic subacute t hyroiditis. Here too, hyperthyroidism spontaneously resolves and often pass es through a hypothyroid phase. This phase often requires therapy, and perm anent mild or severe hypothyroidism may result.