Hyperthyroidism (overactive thyroid)

Hyperthyroidism (overactive thyroid) occurs when your thyroid gland produces too much of the hormone thyroxin. Hyperthyroidism can accelerate your body’s metabolism, causing unintentional weight loss and a rapid or irregular heartbeat.

Several treatments are available for hyperthyroidism. Doctors use anti-thyroid medications and radioactive iodine to slow the production of thyroid hormones. Sometimes, hyperthyroidism treatment involves surgery to remove all or part of your thyroid gland.

Although hyperthyroidism can be serious if you ignore it, most people respond well once hyperthyroidism is diagnosed and treated.

Hyperthyroidism can mimic other health problems, which can make it difficult for your doctor to diagnose. It can also cause a wide variety of signs and symptoms, including:
1. Unintentional weight loss, even when your appetite and food intake stay the same or increase
2. Rapid heartbeat (tachycardia) — commonly more than 100 beats a minute
3. Irregular heartbeat (arrhythmia)
4. Pounding of your heart (palpitations)
5. Increased appetite
6. Nervousness, anxiety and irritability
7. Tremor — usually a fine trembling in your hands and fingers
8. Sweating
9. Changes in menstrual patterns
10. Increased sensitivity to heat
11. Changes in bowel patterns, especially more frequent bowel movements
12. An enlarged thyroid gland (goiter), which may appear as a swelling at the base of your neck
13. Fatigue, muscle weakness
14. Difficulty sleeping
15. Skin thinning
16. Fine, brittle hair

Older adults are more likely to have either no signs or symptoms or subtle ones, such as an increased heart rate, heat intolerance and a tendency to become tired during ordinary activities.
Risk factors
Risk factors for hyperthyroidism, include:

1. A family history, particularly of Graves’ disease
2. Female sex
3. A personal history of certain chronic illnesses, such as type1 diabetes, pernicious anemia and primary adrenal insufficiency

Hyperthyroidism can lead to a number of complications:
1. 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 that increases your risk of stroke, and congestive heart failure — a condition in which your heart can’t circulate enough blood to meet your body’s needs.
2. Brittle bones.
Untreated hyperthyroidism can also lead to weak, brittle bones (osteoporosis). The strength of your bones depends, in part, on the amount of calcium and other minerals they contain. Too much thyroid hormone interferes with your body’s ability to incorporate calcium into your bones.
3. 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.
4. Red, swollen skin.
In rare cases, people with Graves’ disease develop Graves’ dermopathy. This affects the skin, causing redness and swelling, often on the shins and feet.
5. Thyrotoxic crisis.
Hyperthyroidism also places you at risk of thyrotoxic crisis — a sudden intensification of your symptoms, leading to a fever, a rapid pulse and even delirium. If this occurs, seek immediate medical care.