Modem concepts of primary thyroid gland failure

Abstract

Primary thyroid gland failure is a common medical disorder occurring in mild or severe forms in 10% to 15% of our population. Symptoms may be classical and easy to recognize or very subtle, escaping clinical detection. This disorder is more common in females and increases with advancing age. The most important diagnostic test is measurement of the serum thyrotropin (TSH) concentration, which will increase above the normal range in both mild and severe cases. Most clinical effects of thyroid hormone deficiency can be explained by the "nuclear thyroid hormone hypothesis," which states that thyroid hormones act predominantly by effecting the transcription of key genes in affected tissues. Therapy of hypothyroidism is easy, inexpensive, and precise, involving pure L-thyroxine and measuring dose requirements and efficacy by monitoring serum TSH concentrations.