Hypothyroidism: Causes, Screening, and Therapeutic Approach

Abstract

Hypothyroidism is common. It could be due to a primary disorder within the thyroid gland or secondary to pituitary or hypothalamic disease. The clinical presentation of hypothyroidism depends on the duration and severity of the disease. Since thyroid hormones affect the metabolism and function of virtually all nucleated cells, it has diverse clinical manifestations. The most important diagnostic test is the thyroid function test (TFT). Screening for thyroid function is recommended for neonates and elderly patients. Replacement therapy with levothyroxine is indicated. Sickle cell anemia (SCA) is an inherited hemoglobinopathy that frequently causes hypothyroidism. One study conducted among patients with SCA who have high serum ferritin levels assessed the association between gonadal and thyroid hormones with iron indices; it was found that there was a significant relation between serum ferritin level and free T3 and free T4. This was probably due to endocrine dysfunction secondary to high ferritin levels and iron overload.