Classification and Etiopathogenesis of Hypothyroidism

Hypothyroidism is a graded phenomenon characterized by a deficient thyroidal production of thyroid hormone. This condition comprises multiple functional or structural disorders, both congenital and acquired. The clinical expression of hypothyroidism varies between individuals, depending on the cause, duration, and severity of the hypothyroid state, but almost all organs and systems may be affected by a deficiency of thyroid hormone production. This chapter describes the epidemiology, multiple etiologies, and clinical manifestations of hypothyroidism