43 HYPOTHYROIDISM General Discussion Hypothyroidism usually results from decreased thyroid hormone production and secretion by the thyroid gland. Hypothyroidism can either be primary or central, which involves the pituitary gland (secondary hypothyroidism) or hypothalamus (tertiary hypothyroidism) and results in a decrease in the release of active TSH. In the United States, the most common cause of hypothyroidism is chronic autoimmune thyroiditis. Hypothyroidism is far more common in women and in the elderly. In fact, about 2–3% of older women have hypothyroidism. Other risk factors include the presence of thyroid peroxidase antibodies and a high normal level of TSH. Untreated hypothyroidism can result in decreased cardiac output, memory loss, infertility, and sleep apnea. The American Academy of Family Physicians recommends screening for hypothyroidism in patients 60 years of age or older or those patients with symptoms of hypothyroidism, a family history of thyroid disease, a history of autoimmune disease, or type 1 diabetes. Myxedema coma refers to severe complications of hypothyroidism, involving hypothermia and stupor or coma. Myxedema coma can be precipitated by mild illnesses, cold exposure, myocardial infarction, and medications that affect the CNS. Medications That Can Cause Hypothyroidism Amiodarone Ethionamide Interferon alpha Interleukin-2 Iodine excess Lithium Methimazole Propylthiouracil Sulfonamides Causes of Hypothyroidism Primary hypothyroidism • Agenesis and dysgenesis of the thyroid • External irradiation • Hashimoto’s disease (chronic autoimmune thyroiditis) • Infections – Mycobacterium tuberculosis – Pneumocystis carinii • Infiltrative disorders – Amyloidosis – Hemochromatosis – Leukemia – Lymphoma – Sarcoidosis – Scleroderma • Invasive fibrous thyroiditis • Iodine deficiency • Medications • Postpartum thyroiditis • Radioactive iodine therapy • Silent thyroiditis • Subacute thyroiditis • Thyroid hormone resistance • Thyroidectomy Secondary/tertiary hypothyroidism (central hypothyroidism) • Chronic lymphocytic hypophysitis Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: HAIR LOSS INFERTILITY, MALE SYNCOPE THROMBOCYTOPENIA Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on HYPOTHYROIDISM Full access? Get Clinical Tree
43 HYPOTHYROIDISM General Discussion Hypothyroidism usually results from decreased thyroid hormone production and secretion by the thyroid gland. Hypothyroidism can either be primary or central, which involves the pituitary gland (secondary hypothyroidism) or hypothalamus (tertiary hypothyroidism) and results in a decrease in the release of active TSH. In the United States, the most common cause of hypothyroidism is chronic autoimmune thyroiditis. Hypothyroidism is far more common in women and in the elderly. In fact, about 2–3% of older women have hypothyroidism. Other risk factors include the presence of thyroid peroxidase antibodies and a high normal level of TSH. Untreated hypothyroidism can result in decreased cardiac output, memory loss, infertility, and sleep apnea. The American Academy of Family Physicians recommends screening for hypothyroidism in patients 60 years of age or older or those patients with symptoms of hypothyroidism, a family history of thyroid disease, a history of autoimmune disease, or type 1 diabetes. Myxedema coma refers to severe complications of hypothyroidism, involving hypothermia and stupor or coma. Myxedema coma can be precipitated by mild illnesses, cold exposure, myocardial infarction, and medications that affect the CNS. Medications That Can Cause Hypothyroidism Amiodarone Ethionamide Interferon alpha Interleukin-2 Iodine excess Lithium Methimazole Propylthiouracil Sulfonamides Causes of Hypothyroidism Primary hypothyroidism • Agenesis and dysgenesis of the thyroid • External irradiation • Hashimoto’s disease (chronic autoimmune thyroiditis) • Infections – Mycobacterium tuberculosis – Pneumocystis carinii • Infiltrative disorders – Amyloidosis – Hemochromatosis – Leukemia – Lymphoma – Sarcoidosis – Scleroderma • Invasive fibrous thyroiditis • Iodine deficiency • Medications • Postpartum thyroiditis • Radioactive iodine therapy • Silent thyroiditis • Subacute thyroiditis • Thyroid hormone resistance • Thyroidectomy Secondary/tertiary hypothyroidism (central hypothyroidism) • Chronic lymphocytic hypophysitis Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: HAIR LOSS INFERTILITY, MALE SYNCOPE THROMBOCYTOPENIA Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on HYPOTHYROIDISM Full access? Get Clinical Tree
