TOC  |  ENDO

*HYPOTHYROIDISM (MYXEDEMA)                                                                                                            

A. Adult hypothyroidism

1. Goitrous
   a. Autoimmune Hashimoto's thyroiditis
   b. Endemic iodine deficiency
   c. Hereditary defects in hormonogenesis
   d. Goiterogen: iodine, antithyroid drugs (PTU), lithium, amiodarone, etc.
   e. Infiltration: amyloidosis, sarcoidosis, lymphoma, malignancy, etc..
   f. Partial peripheral resistance to thyroid hormone
   g. Circulating thyroid hormone binding antibodies
2. Non goitrous
   a. Idiopathic thyroid atrophy (autoimmune thyroiditis)
   b. Subacute or silent thyroiditis
   c. Iatrogenic: radioiodine Rx, thyroidectomy, irradiation
   d. Pituitary failure (secondaryhypothyroidism): tumors, trauma, idiopathic, Sheehan's synd., etc.
   e. Hypothalamic dysfunction (tertiary hypothyroidism)
   f. Biologically inactive TSH

B. Infantile hypothyroidism (Cretinism)

1. Goitrous
   a. Hereditary defects in thyroid hormonogenesis
   b. Endemic iodine deficiency
   c. Maternal ingestion of goitrogens (iodine, tionamides, lithium)
2. Non goitrous
   a. Idiopathic thyroid agenesis
   b. Maternal I 131 Rx duriing pregnancy
   c. Congenital impaired response to thyrotropin

REF:
Update on the Management of Hyperthyroidism and Hypothyroidism  (Review) - Kenneth A. Woeber
Arch Intern Med.. April 24, 2000;160:1067-1071