Hyperthyroidism: Symptoms, Causes, Treatment And More

What is hyperthyroidism?

Hyperthyroidism, also known as overactive thyroid, is a condition in which the thyroid gland makes excess thyroid hormone. Hyperthyroidism causes the body's metabolism to increase significantly leading to rapid weight loss, irregular or fast heartbeat, sweating, irritability or nervousness. The thyroid gland is a butterfly-shaped gland present in the front of the neck. It controls metabolism or the way a body turns food into energy and also has effects on the heart, cholesterol, bones and muscles. Although the gland in itself is quite small, it has a huge impact on a person's health as every aspect of metabolism is controlled by thyroid hormones.

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What are the causes of Hyperthyroidism?

The thyroid produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which regulate the rate at which the body consumes carbohydrates and fats, maintain body temperature, influence heart rate, and also regulate protein production. Further, the rate at which the thyroid releases T3 and T4 is governed by the pituitary gland and the hypothalamus, both in the brain. The hypothalamus directs the pituitary gland to release thyroid-stimulating hormone (TSH), and the existing levels of T3 and T4 in the bloodstream again determine the amount of TSH released. Also, the thyroid gland releases T3 and T4 hormones depending on the amount of TSH it receives. Thus, if the thyroid gland is diseased and releases excess T3 and T4 on its own, the levels of TSH will drop below normal, and vice versa. In hyperthyroidism, the thyroid gland releases excess T3 and T4 hormones. Several conditions can cause hyperthyroidism, which includes Grave's disease, toxic adenoma, Plummer's disease (toxic multi-nodal goitre) and thyroiditis.

What are the signs and symptoms of Hyperthyroidism?

Common symptoms of hyperthyroidism include:

1. Fatigue
2. Poor concentration
3. Goitre (or visibly enlarged thyroid gland or), thyroid nodules
4. Frequent bowel movements
5. Increased appetite
6. Heat intolerance
7. Increased sweating
8. Irregular menstrual cycles in women
9. Restlessness, nervousness
10. Sleep disorders
11. Weight loss

Sometimes, patients may also experience an uncommon problem known as Grave's ophthalmopathy that affects the eyes. The eyeballs protrude beyond their normal protective orbits and may even bulge out of them, causing the front surface of the eyeballs to become dry. This results from the swelling of tissues and muscles behind the eyes. Signs of Grave's ophthalmopathy include

1. Red or swollen eyes
2. Protruding eyeballs
3. Discomfort or tearing in one or both eyes
4. Blurred vision, inflammation, reduced eye movement, sensitivity to light

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Which specialist should be consulted in case of signs and symptoms?

Patients suspected of having hyperthyroidism must consult an endocrinologist (a doctor who specializes in hormone glands of the body and its disorders). Those with eye involvement may also be referred to an ophthalmologist (eye doctor).

What are the screening tests and investigations done to confirm or rule out the disorder?

1. Physical examination: A physical exam by the doctor will check for high blood pressure, increased heart rate, enlarged thyroid gland, swelling around the eyes, and tremors in the hands.
2. Blood tests: Blood tests are carried out to measure the levels of thyroid hormones (TSH, T3 and T4), cholesterol and glucose levels.
3. Radioactive iodine uptake: The patient is given a small dose of radioactive iodine, which accumulates in the thyroid gland over time since the gland uses iodine to synthesise hormones. The patient is checked after two, six and 24 hours to determine the level of iodine absorbed by the thyroid gland. A high uptake of the radioactive iodine indicates excess production of thyroxine and hyperthyroidism.
4. Thyroid scan: During this test, the patient is injected with a radioactive isotope into the vein present on the inside of the elbow or vein in the hand. The patient is then asked to lie on a table with their head stretched back as a camera produces images of the thyroid gland on a computer screen.

What treatment modalities are available for the management of Hyperthyroidism?

Treatment for hyperthyroidism depends on the exact cause and severity of symptoms. It may be treated in the following ways:

1. Anti-thyroid medication - These medications prevent the thyroid gland from producing excess hormones, reducing the symptoms of the disorder.
2. Radioactive iodine - Radioactive iodine is taken orally, where the thyroid gland absorbs it. This causes the gland to shrink. Symptoms subside within three to six months. However, this treatment can cause the thyroid gland to become underactive, and the patient may require medication to replace thyroxine.
3. Beta-blockers - Though these drugs are generally used to treat high blood pressure, they can reduce a rapid heart rate and prevent palpitations.
4. Surgery - The surgery that removes most of the thyroid gland is called thyroidectomy. The risks involved in undergoing this treatment are damage to vocal cords and parathyroid glands. This is used mostly in cases when a patient cannot tolerate anti-thyroid drugs or is unable to undergo radioactive iodine surgery.

What are the known complications in the management of Hyperthyroidism?

Complications of hyperthyroidism include:

1. Heart issues like rapid heart rate, abnormal heart rhythm, heart failure
2. Osteoporosis
3. Surgery complications like scarring of the neck, hoarseness of voice due to damage to the voice box, low calcium levels due to damage to parathyroid levels and hypothyroidism.

What precautions or steps are necessary to stay healthy and happy during the treatment?

The most important element after diagnosis of hyperthyroidism involves receiving the required medical attention. During treatment too, a patient can cope with the condition and aid healing by practising certain habits:

1. Regular exercise - Helps improve cardiovascular system and muscle tone, reduce appetite and increase energy levels.
2. Relaxation techniques - Helps in maintaining a positive attitude, especially as stress is a risk factor in Grave's disease.

What are the dietary and physical activity requirements during the treatment?

Extra calories and including protein in the diet are beneficial for patients as they cope with weight loss and muscle wastage. Hyperthyroidism can lead to the thinning of bones and it is important to get enough calcium and vitamin D to prevent osteoporosis.