Thyroid Disorders

Hyperthyroidism

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Hyperthyroidism occurs when the thyroid produces excess thyroid hormone. The thyroid gland is located in the neck and produces several hormones, which control metabolism, or the way cells use energy. Hyperthyroidism is a common disorder affecting over two million Americans, most of whom are women.

The most common cause of the condition is Graves' disease, which accounts for 85 percent of cases. Hyperthyroidism also can result from nodular goiter, a condition in which an inflammation of the thyroid occurs due to viral infections or other causes, ingestion of excessive amounts of thyroid hormone, and ingestion of excessive iodine.

Initially, many patients do not experience any symptoms and therefore do not get diagnosed with hyperthyroidism until it is more advanced. In older people, some or all of the typical symptoms of hyperthyroidism may be absent, and the patient may just lose weight or become depressed. Typical symptoms of the condition include:

• Nervousness and irritability
• Increased resting heart rate, which causes heart palpitations
• Heat intolerance and increased sweating
• Tremors
• Weight loss with increase in appetite
• Frequent bowel movements
• Thyroid enlargement causing a lump in the neck
• Pretibial myxdemia, which causes a thick redness on the front of legs and typically occurs with Graves' disease
• Thin, delicate skin and irregular fingernail and hair growth
• Menstrual disturbance, such as decreased flow
• Mental disturbances
• Sleep disturbances, including insomnia
• Changes in vision, eye irritation or exophthalmos, which is a protrusion of the eyes that typically occurs with Graves' disease

Reviewed by health care specialists at UCSF Medical Center.
Last updated May 8, 2007