Thyroid Abnormality

Richard O. Wein and Randal S. Weber

The clinical presentations of symptoms related to thyroid diseases are multiple. This chapter focuses on symptoms related to hypothyroidism, hyperthyroidism, and the presentation of a thyroid mass. Patients with hypothyroidism complain of weight gain, fatigue, cold intolerance, hair loss, rough skin quality, constipation, irregularity of menstrual cycle, change in voice, depression, and rarely the development of carpal tunnel syndrome. In contrast those with hyperthyroidism note heat intolerance, palpitations, atrial fibrillation, anxiety, unintended weight loss, amenorrhea, hair- and skin-related changes, muscular weakness, and sweating. A thyroid mass may produce symptoms of a foreign body sensation in the throat, dysphagia, hoarseness, hemoptysis, and dyspnea.

Hypothyroidism

Besides surgical removal of the thyroid, other etiologies for hypothyroidism include the following:

Late stages of chronic lymphocytic thyroiditis (Hashimoto): Autoimmune lymphocytic infiltration of the thyroid gland. Diagnosis may be assisted with assay for antimicrosomal and antithyroglobulin antibodies.

Radiation: External beam radiation therapy or radioactive iodine (I-131) can lead to progressive fibrosis with lack of adequate function of the gland.

Subacute thyroiditis: Triphasic course: hyperthyroidism, followed by hypothyroidism, with return to euthyroid state. Etiologies are typically viral, or granulomatous (de Quervain disease).

Reidel thyroiditis: Chronic inflammatory disease of the thyroid characterized by dense “woody” fibrosis that extends beyond the thyroid capsule. Etiology is unclear.

Previously diagnosed hypothyroid patient who is noncompliant with thyroid hormone replacement: Failure in medication compliance will result in an elevated thyroid-stimulating hormone (TSH).

Medication related: Lithium, amiodarone, interferon-α, and interleukin-2 can impair the thyroid’s capacity to synthesize thyroid hormone.

Severe iodine deficiency: Iodine is required for the synthesis of triiodothyronine (T3) and tetraiodothyronine (T4). Acute supplementation of large quantities of iodine can result in decreased iodination of thyroglobulin (Wolff-Chaikoff phenomenon) transiently impairing hormone production.