Graves’ disease and hyperthyroidism

What is Graves’ disease?

Graves’ disease is an autoimmune condition. This means that your immune system, which normally protects the body and helps it fight disease, produces antibodies that attack the thyroid gland. These antibodies mimic the action of TSH and drive the gland to produce large amounts of thyroid hormones — a condition called hyperthyroidism.

Although it can appear at any age, in both men and women, Graves’ disease is more common in women aged 20 to 50, who often have a family history of thyroid disease.

What are the complications?

If left untreated, hyperthyroidism can lead to heart failure or to fragile bones (osteoporosis). In addition, pregnant women with uncontrolled Graves’ disease are at higher risk of miscarriage, premature birth and having a baby with a low birth weight.

Graves’ disease can also cause swelling behind the eyes, which can make them bulge outwards. This condition is called Graves’ ophthalmopathy (thyroid eye disease) and is relatively rare.

Signs and symptoms

• Goitre (an enlarged thyroid gland)
• Bulging or swollen eyes, or itchy eyes
• Difficulty breathing
• Anxiety, irritability
• Difficulty sleeping, tiring easily
• A fast heartbeat (tachycardia) or irregular heart rhythm (arrhythmia), trembling hands
• Heavy sweating, sensitivity to heat
• Weight loss despite eating as usual
• Changes in the hair and skin

How is it diagnosed?

Graves’ disease is diagnosed through a clinical examination and a series of tests:

Clinical examination. After taking your full personal and family medical history, your doctor will examine you: feeling your thyroid for any enlargement, examining your eyes for any irritation, checking your pulse and looking for signs of tremor.

Blood tests. When thyroid hormone levels are high, the pituitary gland produces less TSH. Very low TSH levels and high T4 levels in the blood point to hyperthyroidism.

Radioactive iodine uptake test. The thyroid uses iodine to make its hormones; when it makes them in large quantities, it uses more iodine. The test involves swallowing a capsule containing a small, harmless amount of radioactive iodine and then measuring how much iodine the thyroid takes up. When the uptake is high, it is probably Graves’ disease.

How is it treated?

Graves’ disease is curable and, with the right treatment, can easily be brought under control. The available treatments are:

Antithyroid drugs. These reduce the amount of hormone the thyroid produces. The preferred drug is methimazole; in women who are pregnant or breastfeeding, propylthiouracil (PTU) is preferred. These medicines help control the disease but do not cure it permanently, and they are generally not taken for long periods.

Beta-blockers (e.g. atenolol). These control many of the symptoms, mainly the fast heartbeat, tremor and anxiety. They do not cure the disease, however, because the thyroid continues to produce too much hormone.

Radioactive iodine. This cures Graves’ disease, but it usually leads to permanent destruction of the thyroid gland. You will very probably need to take thyroid hormone tablets for the rest of your life afterwards, to keep your hormone levels normal. Radioactive iodine treatment can make the ophthalmopathy worse, but this usually settles with steroid treatment (prednisone).

Surgery (thyroidectomy). This is a permanent solution, but it is not usually the preferred option, because there is a risk of injury to the nearby parathyroid glands (which control calcium metabolism) and to the nerves of the larynx (voice box). It is recommended when neither antithyroid drugs nor radioactive iodine are suitable or effective.

What does this mean for you?

To avoid complications, Graves’ disease needs to be diagnosed and treated early. An endocrinologist — the doctor who specialises in hormone disorders — can diagnose it and give you the right treatment. Follow your doctor’s instructions and book regular check-ups so that your condition can be monitored. If your symptoms come back, see your doctor straight away, as your dose may need adjusting or your treatment may need to change.