Endocrinol Metab Clin N Am 36 (2007) 595–615

Hypothyroidism
Madhuri Devdhar, MD, Yasser H. Ousman, MD*, Kenneth D. Burman, MD
Washington Hospital Center, 110 Irving Street, NW, Room 2A-72, Washington, DC 20010-2975 USA

Hypothyroidism is one of the most common disorders encountered in an endocrine office practice. Hypothyroidism results from reduced thyroid hormone actions at the peripheral tissues. This reduction in thyroid hormone action is, in the vast majority of cases, secondary to reduced thyroid hormone synthesis and secretion by the thyroid gland. Occasionally, peripheral resistance to thyroid hormone is the culprit. The availability of sensitive biochemical tests and effective therapies has simplified the diagnosis and …ver más…

Although isolated deficiency of thyrotropin releasing hormone (TRH) or TSH is possible [3–5], more often the patient who has central hypothyroidism presents with deficiency of other pituitary hormones, and central hypothyroidism is only part of the larger clinical picture of hypopituitarism. Primary hypothyroidism Primary hypothyroidism is responsible for the majority of hypothyroid cases. The following discussion reviews the most common entities that result in primary hypothyroidism. Chronic autoimmune (Hashimoto’s) thyroiditis is the leading cause of primary hypothyroidism in iodine-sufficient areas. Clinically, patients who have Hashimoto’s thyroiditis may present with or without goiter. Pathophysiologically, there is cell-mediated and antibody-mediated destruction of the thyroid gland [6]. Most patients have measurable autoantibodies against different components of the thyroid gland (thyroid peroxidase, thyroglobulin, TSH receptor, TSH blocking antibodies) [7–9]. Occasionally, a patient may present with thyrotoxicosis due to the presence of thyroid-stimulating autoantibodies (Hashitoxicosis) [10]. The prevalence is several times higher in women than in men. The prevalence of overt hypothyroidism varies from less than 1% to 2% of the population. Up to 15% of elderly women have thyroid autoantibodies [11]. Euthyroid individuals, who have detectable thyroid autoantibodies, are at increased risk for developing overt hypothyroidism.