Thyroid – the delicate balance of nature
Too much or too less of anything is not good. God has created human being with so many such parts that even a mild deviation from that delicate balance could throw us off completely from our tracks. One such organ is a butterfly-shaped endocrine gland situated in the neck, which secretes hormones that control metabolism, growth and regulation of normal bodily functions – commonly known as thyroid gland.
How does thyroid gland perform so many functions? Thyroid gland is able to do these by producing hormones, the principal ones are triiodothyronine (T3) and thyroxin or tetraiodothyronine (T4). They regulate metabolism and affect the growth and rate of other systems in the body. Thyroid gland produces T3 and T4 by using iodine and tyrosine. Now, to produce T3 and T4, our thyroid gland needs another hormone called Thyroid Stimulating Hormone (popularly known as TSH). TSH is produced by a group of cells known as thyrotope, which is situated in anterior pituitary gland. This gland is situated near our brain.
When once thrown off the delicate balance of normal limits of thyroid secretion, it could lead to health issues. When this gland secretes less thyroid hormone, the condition is known as hypothyroidism and when it secretes thyroid hormone in excess (overactive thyroid), the condition is known as hyperthyroidism. “Hypothyroidism is by far commoner than hyperthyroidism,” said Suman Bijlani, a Mumbai-based gynecologist wrote in response to an email query sent by this correspondent on behalf of Anand Diagnostic Laboratory. Dr Bijalni has also observed that there is a marked increase in thyroid problems in the recent past. One of the reasons (for increase in numbers) could be stress. Stress weakens the immune system and may encourage production of auto antibodies. It may also impair the delicate balance of hormones throughout the body system. The other reason could be higher detection due to better awareness among people,” she added.
Difference between hypo and hyperthyroidism
- Swelling of feet, face or entire body
- Weight gain
- Slow reflexes and thinking
- Muscle cramps
- Cold intolerance
- Irregular periods
- Low fertility
- Weight loss
- Heat intolerance
- Increased thirst and appetite
- Enlarged heart and protruding eyes (in long-standing cases)
- Iodine is required for the production of thyroid hormones. Dietary deficiency of thyroid hormone can cause hypothyroidism.
- Certain auto-antibodies (antibodies produced against our own organ systems) can cause destruction of the thyroid gland which can decrease its function.
- Congenital hypothyroidism is a condition wherein the hypothyroidism is present at birth and affects the baby in the womb also (See Box).
- Sometimes radiation for cancer treatment can reduce thyroid gland function.
- Certain drugs can temporarily reduce thyroid gland function.
- Stress has been implicated but not proven to increase the risk.
- Women are much more likely to suffer from it than men.
- With increasing age, the risk increases.
- Auto immune antibodies (Grave’s disease is the commonest cause of hyperthyroidism)
- Local tumor of the gland (“hot” nodule), generalised production of excess hormone or inflammation of the thyroid (thyroiditis).
- Temporary hyperthyroidism may be caused immediately post delivery (post partum thyroiditis). It usually resolves without treatment in a few weeks or months.
- Occasionally improper/excess dose of thyroid hormone tablet can mimic hyperthyroidism
Anand Diagnostic Laboratory (ADL), Bangalore’s largest independent medical testing lab received over 1812 blood samples (over a 8-day period -May 31 to June 8 2013) for thyroid testing, of which 25 cases were found to hyperthyroidism and 55 cases of hypothyroidism. About 200 cases reported were found to have isolated increases in thyroid stimulating hormone (TSH). “This could indicate transient or non specific elevation of TSH or thyroiditis or latent hypothyroidism,” said Dr N Jayaram, Director of ADL.
ADL uses Chemiluminescence and Electrochemiluminescence based immunoassay methods to estimate TSH, T3 and T4 values in the blood. “These are tested methodologies that are comparable if not better than other methods such as ELISA and Radio-immuno assay. As such, all methods are standard and it is the laboratory’s operational convenience. In our personal experience, there is more variation from batch to batch when we do ELISA testing,” added Dr Jayaram.
The TSH confusion
Usually T3, T4 and TSH have a reciprocal relationship. “During our routine testing, we come across various combinations of thyroid test results. Rise in T3 / T4 results in a fall in level of TSH and vice-versa. There are few occasions when all three hormones are elevated and this is likely to be associated with a problem in the pituitary gland. Unfortunately, this straightforward relationship is often not evident. This may be the result of various factors of which treatment with thyroid hormones is one. The most commonest feedback or enquiry that we receive in our laboratory – and most other laboratories is with regards to TSH,” added Dr Jayaram.
The TSH levels keep fluctuating throughout the day and are different on different days. TSH levels are significantly lower towards the evening, TSH levels can be higher at menopause, medications such as contraceptives, foods such as cabbage, radish and its family can alter levels of TSH. “What needs to be confirmed before starting medication for an abnormal TSH is whether it is a transient or a persistent abnormality, which means you repeat the test after a week to confirm the same,” added Dr Jayaram. Many a times, the time taken and the dose required for normalization of TSH varies from person to person. “The doctor will have to titrate the dose to achieve this. At times, change of the prescription / brand of medication also helps,” said Dr Jayaram
Cure for thyroid disorders
In case of hypothyroidism there is no particular cure. The condition can be maintained by taking pills. “The treatment is simple, though lifelong. Replacement of the deficient thyroid hormone (thyroxine) in the form of oral tablets containing the same is enough. The tablet is to be taken on empty stomach daily once. The dose is decided by the doctor depending on the severity of the deficiency, and may have to be adjusted till the optimum dose is reached. Doses may need to be changed seasonally also. Hence regular monitoring of thyroid hormones is essential throughout life,” added Dr Bijlani. “But it is very important to note that many people get back to hypothyroid state after stopping medication. Hence it is very important to consult your doctor before you stop medication,” said Dr Jayaram.
Cure for Hyperthyroidism:
- In case of a single “hot” nodule, which is producing the excess hormone, surgical removal is the best option. If the entire gland is overactive, partial or subtotal removal of the thyroid gland is effective.
- For other cases, long-term drug treatment can control the symptoms and effects of hyperthyroidism.
- Radioactive iodine can cause permanent destruction (partial or total) of the thyroid gland. “Many of these patients develop permanent hypothyroidism as a result and need lifelong thyroid hormonal replacement,” added Dr Bijlani.
Congenital hypothyroidism, as the name suggests, is problem that affects a child at birth. This results in partial or complete loss of thyroid function (hypothyroidism). It occurs when the thyroid gland fails to develop or function properly. In many cases either the thyroid gland is absent or located in a wrong place or smaller in size (hypoplastic). In some cases, a normal-sized or enlarged gland is present, but may be producing low levels of thyroid hormones.
When left undetected and untreated, congenital hypothyroidism can lead to intellectual disability and abnormal growth. While it is mandatory to screen infants for congenital hypothyroidism in developed economies like US and many other Asian countries, it is yet pick up pace in India. While some state governments in India are slowly screening and making necessary regulations to mandate neonatal screening for congenital hypothyroidism, the whole country is yet to wake up.
“It is very important for newborns to be screened for hypothyroidism. If detected early, it can be treated and normalcy can be achieved else, it could lead to abnormal intellectual and physical development,” said Savita Naik, a Mumbai-based pediatrician. “We regularly conduct new born screening in our hospital,” she added. She runs Shree Guru Maternity Nursing Home in suburbs of Mumbai.