Monday, 30th October 2017

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Take care of your thyroid

The thyroid is a butterfly-shaped gland situated in the front of the neck. It releases hormones that control many functions in the body such as breathing, heart rate, metabolic rate, body temperature, menstrual cycles and the lipid profile (mainly the triglyceride levels). It is under the control of two other glands in the brain, the pituitary and the hypothalamus. A deficiency of thyroid hormones causes weight gain, abnormal menstrual cycles and elevated triglycerides. These changes are usually picked up early both because of the symptoms, the physical changes in the patient and the fact that the thyroid gland is situated in the front of the neck. Changes in the size, texture or the appearance of nodules are visible and palpable.

By Dr Gita Mathai
  • Published 18.01.16
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The thyroid is a butterfly-shaped gland situated in the front of the neck. It releases hormones that control many functions in the body such as breathing, heart rate, metabolic rate, body temperature, menstrual cycles and the lipid profile (mainly the triglyceride levels). It is under the control of two other glands in the brain, the pituitary and the hypothalamus. A deficiency of thyroid hormones causes weight gain, abnormal menstrual cycles and elevated triglycerides. These changes are usually picked up early both because of the symptoms, the physical changes in the patient and the fact that the thyroid gland is situated in the front of the neck. Changes in the size, texture or the appearance of nodules are visible and palpable.

Thyroid disorders can be diagnosed by doing the thyroid function tests which estimate the level of hormones.

Normal values:

  • Serum thyroxine (T4) 4.6-12 ug/dl
  • Serum triiodothyronine (T3) 80-180 ng/dl
  • Thyroid stimulating hormone (TSH) 0.4-4.2 mcU/mL

Forty two million Indians suffer from thyroid diseases; 80 per cent have low levels of thyroid hormones (hypothyroidism). These individuals benefit from titrated doses of replacement thyroid hormones. The tablets are administered on an empty stomach and the dose is increased every two weeks until it is optimised.

Unregulated usage in unpurified forms (self administered tonics and health supplements for losing weight or gaining height or an appetite) mean that varying amounts of the hormone are being taken. The dosage may even change from day to day. Also, the person may actually have thyroid glands that function normally. Their obesity may be due to an imbalance between caloric intake and expenditure. In this scenario, taking supplements with varying amounts of thyroid hormone can be injurious to health. The pulse rate may go up and there may be heart beat irregularities. It can be fatal.

India has "goitre belts" where iodine deficiency results in an overworked, enlarged thyroid gland and a swelling in the front of the neck. The body cannot store iodine so the daily requirement (adults require 150 micrograms of iodine a day; pregnant and lactating women require 200 micrograms) has to be provided with salt in the food. It is also found naturally in fish and seaweed. The government has tackled this by selling iodised salt in which 30gm of iodine is added per kilo. On an average, 10-15gm of salt is consumed every day, and this provides most people with the required amount of iodine.

Despite this, hypothyroidism can occur if the body produces antibodies to thyroid hormones, a type of autoimmune disease called Hashimoto's thyroiditis, or the gland has been surgically removed. It can also occur with pituitary diseases, or with certain medications like lithium.

The thyroid gland can also go out of control because of excess stimulation from the pituitary gland, or because of cancerous or non-cancerous nodules secreting excess amounts of thyroid hormone. It can be part of Hashimoto's thyroiditis where the body destroys the thyroid hormones produced so that the gland is stimulated to work harder. It can occur owing to painful or painless inflammation of the thyroid gland. It may be due to extraneous administration of iodine or thyroid as part of tonics or health supplements.

A hyperactive thyroid can be treated with medication or radioactive iodine. Anti thyroid medications can be administered for short-term control. Beta blockers slow and regulate the heart rate. Sometimes, hyperfunctioning nodules or even the gland itself may need to be removed.

The thyroid controls almost all functions of the body. Malfuctions may be subclinical and present subtly. It is important to check thyroid functions as part of the master health check up, especially if you are a woman nearing the age of fifty.

 

Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her at yourhealthgm@yahoo.co.in