A number of different benign disorders of the thyroid gland can occur. Some of these thyroid disorders result in overactivity of the gland, leading to excess production of hormones and symptoms of hyperthyroidism. Others result in diminished activity of the gland, leading to decreased production of hormones and symptoms of hypothyroidism. The thyroid hormones T3 and T4 are essential for metabolism; when the gland is not functioning properly, there are a wide range of effects on the body.
The symptoms of thyroid disorders can be subtle, and it may not be readily apparent that the thyroid is to blame. Sometimes patients are clued in because there is thyroid enlargement—called goiter—or a lab test detects a change in the thyroid-stimulating hormone (TSH) level. Other times, a variety of seemingly random symptoms are found. For instance, a patient with hypothyroidism may have weight gain, fatigue, constipation, hair loss, and sensitivity to cold. On the other hand, a patient with hyperthyroidism may be irritable, experience weight loss, have changes in the menstrual cycle and problems with sleep.
Treatment for thyroid disorders includes use of synthetic thyroid hormone, anti-thyroid medications, radioactive iodine, and having the thyroid removed.