How are Thyroid Disorder Investigated and Treated?
The thyroid gland is an endocrine gland in your neck. It makes two hormones that are secreted into the blood: thyroxine (T4) and triiodothyronine (T3). These hormones are necessary for all the cells in your body to work normally.
Thyroid disorders are very common and tend mainly to occur in women, although anybody - men, teenagers, children and babies, too - can be affected. About one in 20 people has some kind of thyroid disorder, which may be temporary or permanent.
The thyroid gland lies in the front of your neck in a position just below your Adam’s apple. It is made up of two lobes - the right lobe and the left lobe, each about the size of a plum cut in half - and these two lobes are joined by a small bridge of thyroid tissue called the isthmus. The two lobes lie on either side of your wind-pipe.
What does my thyroid gland do?
The thyroid makes two hormones that it secretes into the blood stream. One is called thyroxine; this hormone contains four atoms of iodine and is often called T4. The other is called triiodothyronine, which contains three atoms of iodine and is often called T3. In the cells and tissues of the body the T4 is converted to T3. It is the T3, derived from T4 or secreted as T3 from the thyroid gland, which is biologically active and influences the activity of all the cells and tissues of your body.
What can go wrong with my thyroid?
- Hypothyroidism (underactive thyroid) - not enough thyroxine is produced for the body’s needs.
- Hyperthyroidism (overactive thyroid) - too much thyroxine is produced for the body’s needs.
- Hypothyroidism is the most common disorder.
Types of thyroid disease
There are many types of thyroid disease. However, the main conditions present in most thyroid illnesses are hypothyroidism (thyroid under activity) and hyperthyroidism (thyroid over activity).
Thyroid nodules and thyroid cancer
Thyroid nodules are common and treatable but should always be investigated since a small proportion of them are cancerous. The majority of thyroid cancers have a favourable prognostic and require a multidisciplinary approach (endocrinologist, surgeon, nuclear medicine specialist and sometimes oncologist). In the past years there has been a rise in the number of thyroid cancers being identified. There has been no change however, in the mortality rate.
Symptoms of thyroid disease
Signs and symptoms of hypothyroid and hyperthyroid conditions include:
- weak slow heart beat
- muscular weakness and constant fatigue
- sensitivity to cold
- thick puffy skin and/or dry skin
- slowed mental processes and poor memory
- goitre (increased size of the thyroid)
- menstrual disorder
- weight gain
- rapid forceful heartbeat
- muscular weakness
- weight loss in spite of increased appetite
- restlessness, anxiety and sleeplessness
- profuse sweating and heat intolerance
- eye changes
- goitre (increased size of the thyroid)
How is my thyroid gland controlled?
There has to be some sort of mechanism that regulates very carefully the amount of T4 and T3 secreted by your thyroid gland so that the right - the normal - amounts are manufactured and delivered into the blood stream. The mechanism is very similar to that which regulates the central heating in a house where there is a thermostat in, say, the living room, which is set to a particular temperature and which activates the gas- or oil-fired furnace, or boiler that heats the hot water. In the case of the thyroid the ‘thermostat’ consists of a little gland, called the pituitary gland that lies underneath your brain in your skull. The pituitary senses the level of thyroid hormones in your blood stream, just as the thermostat in your living room senses the temperature. Under normal circumstances, if the level drops just a little below normal, the pituitary reacts by secreting a hormone called the thyroid stimulating hormone, also known as TSH, and this hormone activates the thyroid gland to put out more T4 and T3.
Conversely, when the thyroid hormone levels rise above normal the ‘thermostat’ senses this and the pituitary stops secreting TSH so that the thyroid gland stops working so hard and the secretion of T4 and T3 is reduced.