HYPOTHYROIDISM

The word hypothyroidism is a combination of two words; ‘hypo’ meaning below or less than normal and ‘thyroid’ which is the gland that produces the thyroid hormones, important for metabolic health. So, hypothyroidism is when the thyroid gland does not produce sufficient thyroid hormones to meet the normal needs of the body.

The thyroid gland is a butterfly-shaped gland located in the lower front of the neck, just below the Adam’s apple. It is an endocrine gland, and the endocrine system is responsible for coordinating many of the activities of the body. The thyroid gland produces hormones that are secreted into the blood and then transported to every tissue of the body. Its primary function is to produce thyroid hormones. 

These thyroid hormones have many effects on the body. They have a metabolic effect, therefore having effects on almost all the tissue in the body. They affect appetite and the intake of substances. They also have cardiovascular effects as they increase the rate and the strength of the heartbeat. Consequently, they increase blood flow and the temperature of the body. The thyroid hormones also have effect on growth and development. They help in the growth of young people and the maturation of their brain. They can also influence their sleep, way of thinking and sexuality. 

When thyroid hormone levels are becoming very low, the cells of the body will not be able to get enough thyroid hormone and the processes of the body will start slowing down.

Some of the symptoms that the thyroid hormone levels are becoming low are: dry skin, increased sensitivity to cold, fatigue, weakness, constipation, heavy periods, memory loss, unexplained weight gain, depression, slow heart rate, slow movements and speech, coma, etc. But because the symptoms are so variable and nonspecific, the only way to obtain a concrete diagnosis is through a blood test. Also, thyroid disease runs in families, so if you have it, you should explain to your relatives and encourage them to get periodic thyroid-stimulating hormone tests.

CAUSES

There are many reasons the cells in the thyroid gland cannot produce enough thyroid hormone. Below are the list of some of the causes;

Autoimmune disease: This is the most common cause of hypothyroidism. It is when the immune system that protects the body from invading infections mistakes thyroid gland cells and their enzymes for invaders and then fights them. So, there will be no sufficient thyroid cells and enzymes left to make enough thyroid hormone. This may happen because of the genes or some environmental trigger. It is more common in women than men. Autoimmune thyroiditis can begin suddenly or it can develop slowly over time. The most common forms are Hashimoto’s thyroiditis and atrophic thyroiditis.

Surgical removal of part or all of the thyroid gland: Some people with thyroid nodules, thyroid cancer, need to have part or all of their thyroid removed. If the whole thyroid is removed, they will definitely become hypothyroid because the production of thyroid hormone will decrease. Such people will now need to take thyroid hormone. But if part of the gland is left, it may be able to make sufficient thyroid hormone to keep blood levels normal.

Radiation treatment: People with Graves’ disease, nodular goiter, or thyroid cancer are treated with radioactive iodine for the purpose of destroying their thyroid gland. Patients with Hodgkin’s disease, lymphoma, or cancers of the head or neck are treated with radiation. All these patients can lose part or all of their thyroid function.

Congenital hypothyroidism: This is hypothyroidism that a baby is born with. A few babies are born without a thyroid or with only a partly formed one. A few have part or all of their thyroid in the wrong place. In some babies, the thyroid cells or their enzymes are defective although this happens less often.

Thyroiditis: Thyroiditis is an inflammation of the thyroid gland, which is normally as a result of autoimmune attack or by a viral infection. It causes stored thyroid hormone to leak out of the thyroid gland. Consequently, the whole supply of stored thyroid hormone is dumped into the blood at once. Initially, this leakage increases hormone levels in the blood, leading to hyperthyroidism, a condition in which thyroid hormone levels are too high and this may last for up to 3 months. Then later, the thyroid may become underactive, resulting to hypothyroidism which usually lasts 12 to 18 months, but sometimes is permanent. 

Medicines: Medicines such as amiodarone, lithium, interferon alpha, and interleukin-2 can interfere with the function of the thyroid gland and therefore affect the production of thyroid hormones. These drugs are most likely to trigger hypothyroidism in patients who have a genetic tendency to autoimmune thyroid disease.

Too much or too little iodine:  Iodine is a mineral the thyroid gland uses to make hormones. And since iodine comes into the body in food and travels through the blood to the thyroid, proper intake of food containing iodine is required to keep thyroid hormone production in balance. Taking in too much iodine can cause or worsen hypothyroidism.

Rare disorders that infiltrate the thyroid: this is a relatively uncommon cause of hypothyroidism. In a few people, diseases deposit abnormal substances in the thyroid and impair its ability to function. For example, amyloidosis can deposit amyloid protein, sarcoidosis can deposit granulomas, and hemochromatosis can deposit iron. All these substances can affect the functionality of the gland. 

CURE

There is presently no permanent cure for hypothyroidism, and most patients have it for life. However, it can be controlled and managed. Also, there are exceptions: many patients with viral thyroiditis have their thyroid function return to normal, as do some patients with thyroiditis after pregnancy.

Hypothyroidism is usually treated by taking daily hormone replacement tablets called levothyroxine. Levothyroxine replaces the thyroid hormone, which your thyroid gland has failed to sufficiently produce. Hypothyroidism may become more or less severe, therefore, it is unlikely that you will continue to take the same dose. So your dose of thyroxine may need to change over time. You will need to make a lifetime commitment to treatment. But if you take your pills every day and work with your doctor to get and keep your thyroxine dose right, you should be able to keep your hypothyroidism well controlled throughout your life. Your symptoms should disappear and the serious effects of low thyroid hormone should improve.