Thyroid Disorders
Hypothyroidism 1. An underactive thyroid gland with deficient thyroid secretion (thyroxine); lower than normal T4 levels. 2. Results in slowed metabolic processes, affecting body temperature, heartbeat, and slowing of body processes. 3. Etiology: decreased thyroid-releasing hormone secreted by the hypothalamus or by the pituitary gland; atrophy of the thyroid gland; chronic autoimmune thyroiditis (Hashimoto’s disease); overdosage with antithyroid medication. 4. Symptoms may include constipation, depression, dry hair and hair loss, dry skin, fatigue, slow heart rate, swelling of the thyroid gland (goiter), unexplained weight gain or difficulty losing weight, carpal tunnel syndrome. 5. If untreated, leads to myxedema (severe hypothyroidism) with symptoms of swelling of hands, feet, face. Can lead to coma and death. 6. Treatment: lifelong thyroid replacement therapy.
Red Flag: Can result in exercise intolerance, weakness, apathy; exercise-induced myalgia; reduced cardiac output.
Hyperthyroidism 1. Hyperactivity of the thyroid gland. 2. Etiology unknown. 3. Thyroid gland is typically enlarged and secretes greater than normal amounts of thyroid hormone (thyroxine), e.g., Graves’ disease, thyroid storm, thyrotoxicosis. 4. Metabolic processes are accelerated. 5. Symptoms include nervousness, hyperreflexia, tremor, hunger, weight loss, fatigue, heat intolerance, palpitations, tachycardia, goiter, and diarrhea. 6. Treatment: antithyroid drugs. 7. Radioactive iodine may also be prescribed; surgical ablation may be necessary.
Red Flag: Can result in exercise intolerance; fatigue is associated with hypermetabolic state |