Overactive Thyroid (Hyperthyroidism)
Symptoms of Hyperthyroidism
Symptoms of hyperthyroidism may be vague and can often mimic other illnesses and conditions. If you have a very mild form of hyperthyroidism, you may not notice any symptoms. Symptoms are often particularly subtle in the elderly. However, an overactive thyroid often leads to discomfort or even disability that disrupts your everyday activities or routines.
Thyroid enlargement, called a goiter, occurs in most people with hyperthyroidism. You may see or feel a lump in the front of your neck. Sometimes only your doctor will be able to detect a goiter.
Other symptoms of hyperthyroidism include:
- Anxiety, nervousness, and irritability
- Frequent, loose bowel movements
- Difficulty sleeping
- Double vision
- Eyes that bulge out, or "protrude" (in patients with Graves' disease)
- Hair changes, including brittle hair, thinning hair, and hair loss from scalp
- Irregular heart beat (arrhythmia), especially in older adults
- Menstrual cycle changes, including lighter bleeding and less frequent periods
- Muscle weakness, especially in the thighs and upper arms
- Rapid fingernail growth
- Rapid heartbeat, usually over 100 beats per minute
- Shaky hands
- Thinning skin
- Weight loss despite increased appetite
Make an appointment with your health care provider if you have any of these symptoms. It is important to note that these symptoms can be due to other medical conditions and disorders ranging from anxiety to a tumor of the adrenal gland.
How Is Hyperthyroidism Diagnosed?
Blood tests can confirm a diagnosis of hyperthyroidism. Blood tests include those for thyroid-stimulating hormone (TSH). This is a hormone released by the pituitary gland to stimulate the thyroid to make thyroid hormone. Other blood tests include measures of thyroid hormone levels (typically elevated) and thyroid-stimulating antibody (called thyroid-stimulating immunoglobin test) to check for Graves' disease. If your test results are abnormal, your doctor may also order the following tests:
- Thyroid ultrasound, or thyroid scan, to check for nodules or inflammation
- Radioactive iodine uptake test to see your thyroid’s absorption of iodine
- Thyroid scan to see where iodine is in the thyroid
How Is Hyperthyroidism Treated?
There are several different ways to treat hyperthyroidism. Before choosing the one that's best for you, your doctor will consider your age, overall heath, severity of your symptoms, and specific cause of your overactive thyroid.
Treatment options include:
- Anti-thyroid drugs. These medications, including propylthiouracil (PTU) and methimazole (Tapazole), help prevent the thyroid gland from making new hormone. This doesn't permanently damage the thyroid, but some people may have serious side effects.
- Radioactive iodine (RAI) taken by mouth. Overactive thyroid cells quickly absorb this iodine and soon die. This prevents the release of thyroid hormone. Any remaining radioactive iodine disappears from the body within a few days. It may take a few months for the therapy to relieve hyperthyroidism symptoms, and a second dose may be needed. People who have this treatment will develop an underactive thyroid (hypothyroidism), and will need thyroid hormone supplements for the rest of their life. This therapy cannot be done during pregnancy.
- Surgery to remove all or part of the thyroid, called a thyroidectomy. Most people who have this procedure eventually develop an underactive thyroid and will need to take thyroid hormone-replacement medication for the rest of their life.
- Beta-blockers to slow down your heart rate. These medicines do not lower your thyroid hormone levels but help relieve symptoms related to a rapid heart rate.
After treatment, you will need regular blood tests to check your thyroid hormone levels. Your doctor may need to adjust your medication dose from time to time.