It is quite tiny but vitally-important for numerous tasks in the human body. Each and every cell requires the hormones emanating from this gland not only to regulate cell-differentiation but also for cell energy consumption. The rate of metabolism and the hormones secreted from the thyroid are inextricably linked, says Consultant Endocrinologist Dr. Chaminda Garusinghe [...]

The Sunday Times Sri Lanka

Small but vital

Consultant Endocrinologist Dr. Chaminda Garusinghe discusses the functions of the thyroid and problems associated with this gland including goitre

It is quite tiny but vitally-important for numerous tasks in the human body. Each and every cell requires the hormones emanating from this gland not only to regulate cell-differentiation but also for cell energy consumption.

The rate of metabolism and the hormones secreted from the thyroid are inextricably linked, says Consultant Endocrinologist Dr. Chaminda Garusinghe attached to the National Hospital of Sri Lanka. These hormones help regulate metabolism, allow us to grow, produce offspring and carry out a host of different functions.

In the form of a brownish-red butterfly, the thyroid nestles in the front of the neck, just below the Adam’s apple on either side of the wind-pipe (trachea). Weighing about 30gms, it is flanked at the rear by four para-thyroid glands.

Thyroxine (T4) and triiodothyronine (T3) are the hormones or special chemicals put out by the thyroid which is part of the endocrine system and plays a crucial role in the development of the brain and the proper functioning of the nervous system, even while a baby is still in the womb, MediScene learns.

Describing the functioning of the thyroid, Dr. Garusinghe says that it extracts iodine, which is present in low concentrations in blood, and uses it to produce the thyroid hormones. Thyroid deficiency could be quite common owing to a lack of iodine in the food consumed by people, but this has now been overcome by the universal iodization of salt that is used in cooking .

Dr. Garusinghe picks out the malfunctioning of the thyroid and attributes it to iodine deficiency or an intrinsic disease of the gland such as thyroiditis.

An iodine deficiency could also result in goitre (swelling of the thyroid gland). Sometimes, substances dubbed ‘goitrogens’ could cause thyroidal problems, it is understood. These could take the form of drugs, chemicals or food and this Endocrinologist says some very nutritious vegetables fall into this category — manioc when crushed and not de-toxified by soaking, soyabeans, spinach (nivithi) and cruciferous vegetables of the Brassica family which includes broccoli, cauliflower, cabbage, Chinese cabbage and radish are some of these.

‘Endemic goitre’, meanwhile, could come about due to lack of iodine in the food and water consumed by certain communities, particularly in mountainous regions across the globe. For, iodine is a trace element in seawater and soil and enters the food chain through plants growing in iodine-rich soil or fish or plants from the sea. Iodine is found in seafood including shellfish and seaweed, plants such as cereals or grains and cow’s milk, it is learnt.

Pointing out that the presence of a goitre does not mean that thyroxine levels are abnormal, Dr. Garusinghe says that a simple blood test can indicate whether there is a problem or not.

What needs to be checked out is whether the goitre is putting pressure on the surrounding structures or compressing the wind-pipe which could bring in its wake respiratory issues such as breathing difficulties and a nocturnal cough. Sometimes, rarely, the goitre could press on the food-pipe causing dysphagia. Some goitres may create trouble by growing into the chest cavity behind the sternum (breast-bone).

Once it is established that there is a goitre, a thorough assessment whether thyroid hormone levels are normal, other structures are affected by the enlarged gland or there is a malignancy has to be checked out. There are no medications to retard or shrink the progress of an established goitre and the answer would be surgery, he says.

Referring to a goitre which harbours a malignancy (cancer), he says that an ultrasound scan is essential to ascertain whether the nodules in the goitre have any suspicious features. Sometimes it is obvious and then a fine-needle aspiration test would follow, performed on the suspicious area of the gland to obtain a few cells to be examined by a histopathologist. Although it is not 100% sensitive, it is a good investigation.

Urgent surgery to remove the goitre may be needed if it is having an impact on other structures, is growing rapidly or is cancerous. If the nodule is small and has suspicious features, it should be biopsied under ultrasound guidance, he says.

If it is an innocent goitre without rapid growth, conservative management would suffice but periodic assessment is essential. In such cases, sometimes surgery is performed for cosmetic reasons due to a patient’s preference.

“Thyroid-removal is not simple but major surgery carried out under general anaesthesia. These days due to the vast experience and skill of surgeons, complications are minimal,” says Dr. Garusinghe. “The complications could include long-term paralysis of the vocal cords which could result in a voice-change or loss of voice.”

If the para-thyroid glands are damaged or the supply of blood to them is harmed, there will be a drop in blood-calcium levels, resulting in numbness, tightness, seizures and also cramps. There could still be recovery with time, but if the damage is permanent, calcium and Vitamin D will have to be taken life-long, according to him.

“Once the thyroid is removed, thyroxine will have to be taken daily with blood tests, once in three to six months, to check thyroxine levels. This regimen is also essential during pregnancy and has to be closely monitored and dose-adjustments made when necessary. Otherwise, the impact on the baby and his/her brain development could be disastrous,” adds Dr. Garusinghe.

Problems associated with the thyroid

Hypothyroidism is caused by an underactive thyroid which does not produce adequate thyroxine to meet the body’s needs. It is common in middle-aged women. If a woman is sub-fertile or having irregular menstruation; a young person has high cholesterol; or a person presents with a low heart-rate, hypothyroidism should be suspected.

Symptoms – Lethargy, tiredness, weakness, feeling sleepy, feeling cold, dry skin, hair-loss, hoarseness of voice, constipation, joint pains and muscle cramps, depression, weight-gain, menstrual irregularities and sub-fertility in women and erectile dysfunction in men.

Treatment — Thyroxine tablets would have to be taken life-long.

Hyperthyroidism is caused by an over-active thyroid which has excessive secretion of thyroxine. It is a common thyroid disease in the country, affecting people of all ages.

Symptoms – Weight loss despite increased appetite, anxiety, increased sweating, heat intolerance, tremors, hyperactivity and palpitations and in women menstrual irregularities.

Prominent or bulging eyes, redness in the eyes, tearing, double vision and reduced vision could also be part of the condition indicating clearly that it is Graves’ Disease.

An involvement of the heart, meanwhile, could lead to heart failure.

Treatment-Tablets of carbimazole or methimazole taken for about 6 to 18 months may bring about a permanent cure. If the disease recurs, Radioactive Iodine (RAI) Therapy would be needed at which time the patient should avoid pregnancy for one year after such treatment.

Thyroiditis or an inflammation (swelling) of the gland could be caused by a viral disorder. This, however, would pass with time but a follow-up with a doctor is important to detect a possible subsequent malfunction of the gland.


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