Hyperthyroidism (overactive thyroid) is a condition in which your thyroid gland produces too much of the hormone thyroxine. Hyperthyroidism can accelerate your body’s metabolism significantly, causing sudden weight loss, a rapid or irregular heartbeat, sweating, and nervousness or irritability.
Hyperthyroidism can mimic other health problems, which may make it difficult for your doctor to diagnose. It can also cause a wide variety of signs and symptoms, including:
- Sudden weight loss, even when your appetite and the amount and type of food you eat remain the same or even increase
- Rapid heartbeat (tachycardia) — commonly more than 100 beats a minute — irregular heartbeat (arrhythmia) or pounding of your heart (palpitations)
- Increased appetite
- Nervousness, anxiety and irritability
- Tremor — usually a fine trembling in your hands and fingers
- Changes in menstrual patterns
- Increased sensitivity to heat
- Changes in bowel patterns, especially more frequent bowel movements
- An enlarged thyroid gland (goiter), which may appear as a swelling at the base of your neck
- Fatigue, muscle weakness
- Difficulty sleeping
- Skin thinning
- Fine, brittle hair
When to see a doctor
If you experience unexplained weight loss, a rapid heartbeat, unusual sweating, swelling at the base of your neck or other symptoms associated with hyperthyroidism, see your doctor. It’s important to completely describe the changes you’ve observed, because many signs and symptoms of hyperthyroidism may be associated with a number of other conditions.
If you’ve been treated for hyperthyroidism or currently are being treated, see your doctor regularly as advised so that he or she can monitor your condition.
Hyperthyroidism, particularly Graves’ disease, tends to run in families and is more common in women than in men. If another member of your family has a thyroid condition, talk with your doctor about what this may mean for your health and whether he or she has any recommendations for monitoring your thyroid function.
Hyperthyroidism can lead to a number of complications:
- Heart problems. Some of the most serious complications of hyperthyroidism involve the heart. These include a rapid heart rate, a heart rhythm disorder called atrial fibrillation and congestive heart failure — a condition in which your heart can’t circulate enough blood to meet your body’s needs. These complications generally are reversible with appropriate treatment.
- Brittle bones.
- Eye problems. People with Graves’ ophthalmopathy develop eye problems, including bulging, red or swollen eyes, sensitivity to light, and blurring or double vision. Untreated, severe eye problems can lead to vision loss.
- Red, swollen skin.
- Thyrotoxic crisis.
Tests and diagnosis
Hyperthyroidism is diagnosed using:
- Medical history and physical exam. During the exam your doctor may try to detect a slight tremor in your fingers when they’re extended, overactive reflexes, eye changes and warm, moist skin. Your doctor will also examine your thyroid gland as you swallow to see if it’s enlarged, bumpy or tender and check your pulse to see if it’s rapid.
- Blood tests. A diagnosis can be confirmed with blood tests that measure the levels of thyroxine and TSH in your blood. High levels of thyroxine and low or nonexistent amounts of TSH indicate an overactive thyroid. The amount of TSH is important because it’s the hormone that signals your thyroid gland to produce more thyroxine. These tests are particularly necessary for older adults, who may not have classic symptoms of hyperthyroidism.
If blood tests indicate hyperthyroidism, your doctor may recommend one of the following tests to help determine why your thyroid is overactive:
- Radio iodine uptake test.
- Thyroid scan.
Treatments and drugs
Several treatments for hyperthyroidism exist. The best approach for you depends on your age, physical condition, the underlying cause of the hyperthyroidism, personal preference and the severity of your disorder:
- Radioactive iodine.
- Anti-thyroid medications.
- Beta blockers.
- Surgery (thyroidectomy).
If Graves’ disease affects your eyes (Graves’ ophthalmopathy), you can manage mild signs and symptoms by avoiding wind and bright lights and using artificial tears and lubricating gels. If your symptoms are more severe, your doctor may recommend treatment with corticosteroids, such as prednisone, to reduce swelling behind your eyeballs. In some cases, a surgical procedure may be an option:
- Orbital decompression surgery.
- Eye muscle surgery.
Lifestyle and home remedies
Once you begin treatment, symptoms of hyperthyroidism should subside and you should start feeling much better. The following suggestions also may help:
- Ask your doctor about supplementing your diet.
- Get enough calcium and vitamin D.
If you have Graves’ ophthalmopathy or dermopathy, the following suggestions may help soothe your eyes or skin:
- Apply cool compresses to your eyes.
- Wear sunglasses.
- Use lubricating eyedrops.
- Elevate the head of your bed.
- Try over-the-counter creams for swollen skin.