Hyperthyroidism

Overview
  • Hyperthyroidism is a clinical syndrome caused by excess levels of circulating thyroid hormones beyond that required to meet physiological demands. Multiple etiologies can lead to hyperthyroidism the most important is Graves Disease.
Clinical Consequences
  • Much of the clinical syndrome of hyperthyroidism can be predicted given the physiological actions of thyroid hormones discussed in Thyroid Hormone Physiology. Excess thyroid hormone results in increased whole-body metabolism which manifests as an increased basal metabolic rate]] that can lead to weight loss despite increased appetite. The resultant increased in body temperature may lead to diaphoresis and heat intolerance. In addition, patients may display tachycardia and palpitations due to increased sympathetic activity. Hyperthyroidism is a common of cause of pushing elderly hearts into atrial fibrillation.
  • Thyroid hormone stimulation of the CNS can lead to tremors, irritability, and nervousness. Excess GI Motility often leads to a Dysmotility Diarrhea. A classic symptom of hyperthyroidism is exopthalmos. Finally, certain causes of hyperthyroidism may yield a goiter.
Treatment
  • Treatment of hyperthyroidism can be achieved either pharmacologically or surgically. A pharmacological approach involves administration of propylthiouracil or methimazole, drugs which inhibit thyroid peroxidase and thus synthesis of active hormone. Alternatively, the thyroid gland can be surgically removed or radiatively ablated with radioactive 131I which concentrates in the thyroid gland and then destroys the tissue. Following iatrogenic destruction of the thyroid gland, the patient must then be treated for hypothyroidism for the rest of their life with thyroid hormone replacement therapy (levothyroxine).