What is hyperthyroidism?
When your thyroid gland produces more thyroxine than the body needs, it results in hyperthyroidism. Increased thyroxine levels in blood due to this or other causes (eg: excessive intake of thyroxine supplements) affects various body systems and result in a condition named thyrotoxicosis.
What are the symptoms of hyperthyroidism?
A patient with hyperthyroidism may have the following symptoms:
- Decreased sleep
- Feeling warm/ increased sweating
- Increased hunger
- Weight loss
- Irregular menses
- Prominent eyes/ stare
- Thyroid enlargement
In some patients with hyperthyroidism, eye symptoms may be prominent. They may have bulging of the eye ball, eye pain, discomfort, difficulty of eye movement, blurring of vision or double vision. If untreated it may result in loss of vision.
If hyperthyroidism is not treated early, it may result in a life threatening condition called thyrotoxic storm.
What are the causes of hyperthyroidism?
The most common cause of hyperthyroidism is Grave’s disease. In this condition your body produces an antibody which drives your thyroid to produce more thyroxine. Other causes include nodules in the thyroid gland, which may be single or multiple. A rare cause of hyperthyroidism is a pituitary tumor producing excessive TSH. Symptoms similar to hyperthyroidism may result from inflammation of the thyroid gland (thyroiditis) or excessive intake of thyroxine hormone.
How is hyperthyroidism diagnosed?
Hyperthyroidism is diagnosed by clinical examination followed by blood tests for T4 and TSH. In hyperthyroidism, T4 is elevated and TSH will be suppressed. In some cases, you doctor might ask for T3 levels or thyroid antibody levels. To differentiate between various causes of thyrotoxicosis and to decide on which treatment modality your need, a nuclear scan of the thyroid gland (Technetium99m or Iodine 131/125) may be asked for.
How is hyperthyroidism treated?
Most patients with hyperthyroidism are initially treated with medications. Anti thyroid drugs like carbimazole, methimazole or propylthiouracil (PTU) may be prescribed by your doctor. These medications decrease the thyroxine production from the thyroid gland in a few weeks. Your doctor may also advise you to take medications like propranolol and anti anxiety drugs for faster relief.
Once anti thyroid medications are started, you need regular monitoring. You may be asked to repeat blood test in 1-2 months and follow up with the doctor. Your doctor will adjust the dose of medication. In some patients, it may be possible to gradually decrease and stop the medications, resulting in remission of the disease. In others, the disease recurs and your doctor may advise you to consider alternate methods of therapy.
Other than medications, hyperthyroidism may be treated by radio iodine therapy or surgery. In radioiodine therapy, patient is asked to take radioactive iodine orally, which is specifically taken up by the thyroid gland, minimizing any radioactive damage to other parts of the body. You should avoid close contact with other persons, especially small children, for a few days after the radio iodine therapy. It typically takes a few weeks to months to be completely effective. In the interim, your doctor may advise you to take anti thyroid medications. In some patients, a second dose of radio iodine may be required.
Surgery is the other option for treatment of hyperthyroidism. In this, patient’s thyroid gland is removed. Surgery for hyperthyroidism should be done only in specialized centers, having an endocrinologist, and by an experienced surgeon, who is well supported by good anesthesia team. Patient’s symptoms should be well controlled by medications by the endocrine team before surgery is attempted. Otherwise it may result in a serious condition called thyrotoxic storm and even death of the patient.
After surgery and often after radio iodine therapy, patient may need thyroid hormone replacement lifelong.
What are the side effects of anti thyroid medications?
Anti thyroid medications result in decrease in blood levels of thyroid hormones. As the levels come down too low, you may experience some fatigue, weight gain and body aches. These usually settle with adjustment of medication dose. Rarely, there may be variations in liver enzymes and your doctor might ask you to do liver function tests to monitor that. In a very small percentage of patients, there might be a drop in white blood cell count, predisposing them to infections.
If you develop high fever with sore throat while you are on anti thyroid medications, you should immediately stop the medication, do complete blood counts and see your doctor as soon as possible.