HYPOTHYROIDISM : WHEN THE THYROID GOES COLD!

Guest Article by Dr Krishna G Seshadri MBBS, AB (Internal Medicine), AB(Endocrinology) about Hypothyroidism

Hypothyroidism...

The thyroid gland is a small butterfly shaped gland in the bottom of the neck lying in front of the windpipe. It is a ductless gland that secretes a hormone called thyroxin.Thyroxin is an important hormone that performs myriad functions that include maintaining the body's metabolism and heat regulation. It is also important for the growth of the body and the brain, normal menstrual function in women and overall well being of the body and the mind. Disturbances in thyroid function are very common in India particularly in women. Decreased functioning of the thyroid called hypothyroidism is the most common condition and will be the focus of this article.

Causes...

Hypothyroidism can occur due to many causes. In newborns and in children it may be because of the absence or wrong location of the thyroid gland, or due to faulty hormone production. Hypothyroidism can also occur if a person has the thyroid removed due to surgery. The most common cause however, is the destruction of the thyroid by the person's own body cells by a process called  "autoimmunity".

Normally, our body has a defense system made up of cells that destroy foreign invading organisms like bacteria. Each cell of our body has an "identity badge" that tells these cells that they are "not foreign" and therefore must not be destroyed. In some persons, these defence cells by mistake recognize the body's own cells as foreign and destroy it - this process is called autoimmunity. Some examples of autoimmune disease are rheumatoid arthritis, lupus and of course hypothyroidism. This autoimmune process destroys the thyroid cells and causes decreased secretion of the thyroid gland. This results in hypothyroidism

Symptoms...

The symptoms of the hypothyroidism are varied. The most common symptoms are unexplained fatigue, weight gain despite having a decreased appetite, hoarseness of voice, constipation, hair loss, thickening and drying of skin, inability to tolerate cold environments, inability to remember, and difficulty in getting up from a sitting position. In women, additional symptoms include menstrual disturbances including irregular menses, excessive menses and in severe cases - absent menses. Women who have delivered recently are particularly prone to develop hypothyroidism and these women may have difficulty in losing the weight gained during pregnancy, non-resumption of menses and depression. In children, the symptoms include weight gain, lack of gain in height, and poor performance in school. However many patients may be asymptomatic and in these patients often the condition is diagnosed by the doctor who orders the test based on clinical suspicion and examination.

Consequences...

Untreated hypothyroidism can lead to progressive weight gain, thickening of the skin, dulling and slowing of the mental process. The heart can become enlarged and not function properly. Fluid can accumulate in the bag that surrounds the heart. The arteries that supply the heart can also become clogged - leading to heart attacks. Children can become short, stunted and mentally retarded - "cretins".  Hypothyroidism can also lead to menstrual irregularity and infertility in women. In addition, it can also cause depression and a psychotic condition called myxedema madness. In extremely severe hypothyroidism every body function becomes slowed down and the patient may lose consciousness - a condition called myxedema coma.

Who should be tested for hypothyroidism?

Persons with any of the above symptoms must be tested for hypothyroidism. In addition, thyroid testing must be done in the following persons irrespective of symptoms:

1. Persons with a swelling of the thyroid.
2. All new born children must have a thyroid test on the fourth day after delivery  - hypothyroidism occurs in 1 out of every 4000 children born and is the most correctable form of mental retardation if detected early. In western nations - the law mandates that all newborn children must have a blood test for thyroid deficiency. While it is not a law in our country, more and more doctors feel that this is an important test that prevents significant problems.
3. Women who are pregnant - Recent research has shown that women who are hypothyroid during pregnancy may have children with lower intelligence quotients (IQ) than women who are normal. So many doctors get thyroid functions in pregnant women.
4. Women after delivery: A form of hypothyroidism that masquerades as depression is very common in women who have delivered and this can be treated if recognized early.
5. Persons on certain drugs like the cardiac drug amiodarone and the psychiatric drug lithium are more likely to have thyroid problems and must have testing done.
6. Older men and women may have thyroid problems without symptoms and need to be tested.

What test is needed?

For most patients a simple blood test that will measure the thyroid hormone (called Free T4) and the hormone secreted by the gland that controls the thyroid (pituitary gland) called TSH is sufficient. The doctor will make a decision for treatment based on this test, or order additional tests if needed.

What is the treatment for hypothyroidism?

The treatment for hypothyroidism is taking a medicine called levo - thyroxin (Eltroxin, Thyrox, Thyronorm) in the appropriate doses decided by the doctor. This drug will perform the work of the hormone normally secreted by the gland.  It must be remembered that the drug does not stimulate or cure the thyroid - it merely performs its function. Therefore, the drug must be taken in most people for the rest of their life and cannot be stopped once the test becomes normal. The doctor will do a test 6 - 8 weeks after starting the medicine to assess whether the dose is correct or not and make adjustments. Once the correct dose is reached, testing is usually done once a year. When taken in the correct dose - the drug has no side effects.

The medicine must be taken on an empty stomach and it is sufficient to take the medicine once a day. If a person is taking drugs like iron, medicines to reduce cholesterol or antacids, these medicines must be taken at a different time after consultation with the doctor. Unlike other medicines, which must be stopped when a woman becomes pregnant, the dose of the thyroxin must be increased in pregnancy and in no account stopped.

Can I use thyroxin to lose weight?

No. The only use of thyroxin is to treat hypothyroidism. If used to treat conditions like obesity or depression or just as a tonic, it can have side effects including causing problems with the heart and loss of bone called osteoporosis. It is not advisable to take thyroid medicines without the advice of the doctor.

In summary hypothyroidism is a very common condition among Indian women. The disease can be easily suspected and diagnosed. The treatment is simple and effective. In most people, treatment is lifelong.

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