Understanding thyroid problems
‘What in the world is a thyroid problem?’ a young child may ask.
Well, in order to fill the void on thyroid, let’s start right from the basics. To start with, the thyroid gland is an endocrine gland, meaning ductless gland, situated just below the larynx (vocal box). The gland consists of two lobes lying on either side of the wind pipe. Both lobes are connected by thin tissue called isthmus. In view of this, it looks like a dumbbell and it weighs 20 gm in adults. The lobes and isthmus consist of numerous tiny follicles. The space inside the follicles is filled with a fluid called colloid in which thyroid hormones are stored in a protein called thyroglobulin.
Two thyroid hormones
Thyroid gland produces two hormones – Triiodothyronine (T3) and Thyroxine (T4) – which are secreted directly into our blood. These are produced in the follicles. C cells of thyroid gland produce another hormone called calcitonin which buffers the calcium level in our body. The thyroid hormones (T3 and T4) regulate the consumption of oxygen by tissues and cholesterol in the blood. Also, these hormones increase protein synthesis in all body cells.
Secretions of T3 and T4 are under the control of thyroid stimulating hormone (TSH) which is produced by the pituitary gland in the brain. When the levels of T3 and T4 go down, TSH production increases, so that their levels can be maintained. Reverse is also true – when T3 and T4 increase, TSH level comes down. This mechanism of keeping the secretions of T3 and T4 levels under control is called biofeedback mechanism, but some degree of intrathyroidal autoregulation also exists. Pituitary gland is again under the control of master gland hypothalamus that liberates a hormone called thyrotropin releasing hormone (TRH) which eventually regulates the secretion of TSH.
Role of iodine
Iodine is the raw material responsible for the production of thyroid hormones. This chemical element is naturally present in water and daily food we routinely consume. However, iodine content in drinking water varies from one region to another. Let’s pick up Delhi as an example. Concentration of iodine in Delhi water is comparatively low as it measures less than one part per million. One of the major sources of iodine is iodized table salt that we consume daily.
In general, iodine deficiency leads to goiter, which in turn may liberate less hormone and causes metabolic problems. In many parts of India, where people do not maintain iodine in their daily food intakes, iodine deficiency gives rise to goiter as well as other relative thyroid problems like developmental delays in both children and adults. Such iodine menace occurs primarily among the people living in the sub-Himalayan regions as well as flood-prone areas, deltas and sea coasts.
Three major ailments
We can broadly categorise three types of illnesses that can be developed as a result of thyroid problems. The first is thyrotoxicosis – excess production of thyroid hormone; secondly, hypothyroid – less production of thyroid hormone; and the third, tumor – tumor of thyroid glands. Thyrotoxicosis or hyperthyroidism leads to increase in metabolic activity. Generally people suffering from this thyroid-disorder start losing weight, irrespective of eating well in a normal way. They always show symptoms of great anxiety, tremor of hands and their eyes sometimes protruded (exopthalmos). Rapid pulse and menstrual disorder are also common symptoms.
Hypothyroid—less production of thyroid hormone—may lie in the thyroid gland, which is called primary hypothyroidism, or in the pituitary gland called secondary hypothyroidism. In hypothyroidism, metabolic rate becomes slow accompanied by weight increase, dry skin, hair loss, lethargic, weakness, cold intolerance and no interest in life. It can also cause obstinate constipation and irregular periods in females. This is a more common problem than hyperthyroidism. It occurs more often in females at the menopause time.
There is also a special type of hypothyroidsm which occurs in the newborn called cretinism. This is due to the deficiency of thyroid hormones. Clinical features suggesting cretinism are respiratory difficulty, jaundice, and feeding difficulty at the time of birth. Spout of open mouth, umbilical hernia and hypotonia of muscles may also be present. If not diagnosed early, it may lead to subnormal intelligence to the extent of madness. It is prudent that every newborn should be checked and tested for hypothyroidism
Now the tumor! It can be either benign (adenomas) or cancerous. Thyroid tumors or adenomas of cancerous kind are as rare as only about 0.5 percent of all cancers. However, research findings show that peak incidence occurs in people in their 50s and women are prone twice as frequently as men. As thyroid problems are alarming in all age groups, a timely vigil on this health menace is always the need of the hour now!
Dr Narottam Bhardwaj completed MBBS in 1973 and MD in Medicine in 1978 from Maulana Azad Medical College, University of Delhi. He worked for three years in LNJP and GB Pant Hospitals, New Delhi from 1982. He has been in private practice as a consultant physician to various hospitals like Indraprastha Apollo Hospital, etc. At present he is senior consultant- Internal Medicine at Max Hospital, Saket; Sukhda Hospital, GK-I, New Delhi. He is also Medical Advisor to Power Grid Corporation, Power Finance Corporation and SIEMENS. He has published several papers on diabetes, hypertension and heart disease. He has special interest in diabetes. He is a member of Delhi Medical Association and American Diabetic Association.