What Happens

If your thyroid gland makes too much thyroid hormone, you may have symptoms of hyperthyroidism. Most hyperthyroidism is caused by an immune system problem called Graves' disease. At first, your hyperthyroidism may make you feel hot, have tremors in your hands, or lose weight. Over time, you may notice that your heart is beating fast, that you feel anxious, or that you are having a lot of bowel movements. You may also feel like you just don't have as much energy as usual.

Hyperthyroidism typically does not go away on its own. Most people need treatment to make hyperthyroidism go away. After treatment, many people develop hypothyroidism (too little thyroid hormone).

In rare cases, hyperthyroidism can cause a life-threatening condition called thyroid storm, which occurs when the thyroid gland releases large amounts of thyroid hormones in a short period of time.

What Increases Your Risk

You are more likely to have hyperthyroidism if:

• You are female.
• You have a family history of thyroid problems. People who have close relatives with Graves' disease or other thyroid problems are more likely to develop hyperthyroidism.
• You have an autoimmune disease, such as Addison's disease or type 1 diabetes.
• You smoke cigarettes. People who smoke are more likely to have Graves' disease and are more likely to have Graves' ophthalmopathy.