Published in City Times
Hyperthyroidism affects approximately 1 in every 1000 women and is roughly ten times more common in women than men. While it can affect all age groups of people, it is most commonly seen in individuals above the age of 15 years. Mothers suffering from Graves’ Disease, could give birth to babies who suffer from hyperthyroidism called Neonatal Grave's disease, says Dr. Belal Alshammaa, Diabetologist and Endocrinologist, American Hospital, Dubai.
What is Hyperthyroidism and how does it occur?
Hyperthyroidism is the overproduction of thyroid hormones by an overactive thyroid gland. The thyroid is a gland located in the front of the neck which produces the hormones thyroxine, T4 and triiodothyronine, T3. These hormones regulate the body’s metabolic rate by helping to form the protein RNA, ribonucleic acid, thereby enhancing oxygen absorption in the cells of the body. The production of T3 and T4 in turn, are controlled by the Thyroid Stimulating Hormone (TSH) produced by the pituitary gland.
Hyperthyroidism may take the form of Graves’ disease, Basedow’s, throtoxicosis or diffuse toxic goiter, resulting from an overabundance of thyroid hormone. A small part of the thyroid may become overactive as in there being a nodule or toxic adenoma, giving rise to the condition. Sometimes, a pre-existing goiter which is an enlarged thyroid, may overproduce the hormones. Also, subacute thyroiditis may occur due to an inflammation of the gland and consequent overproduction of the hormones.
What are the causes of Hyperthyroidism?
Hyperthyroidism is often associated with the body's over-production of auto-antibodies in the blood which cause the thyroid to grow and secrete excess thyroid hormone. The tendency to hyperthyroidism is often inherited, particularly by female family members. The condition may also be triggered by dietary additives or drugs but no other identifiable contributory factors are yet known.
How do the symptoms of hyperthyroidism manifest themselves?
Heat intolerance, palpitations, muscle weakness, tremors, anxiety, a faster working nervous system, profuse sweating, moist skin, loss of weight with increase in appetite, sleeplessness, and diarrhea. Women may have decreased menstrual flow and irregular cycles. An elevated body temperature may be an indication of a heightened metabolic rate and hyperthyroidism.
How is hyperthyroidism diagnosed?
Just by looking at a patient you can tell she’s suffering from hyperthyroidism, based on the clinical symptoms. The combination of physical examination, clinical history and a simple blood test to determine the amount of thyroid hormone in the patient's blood may be sufficient to diagnose hyperthyroidism. A radioactive thyroid scan and a radioactive iodine uptake (RAIU) test may be done to confirm diagnosis. A radioactive thyroid scan may be done to evaluate thyroid nodules, or to detect areas of the thyroid gland that are overactive or underactive. A radioactive substance called a tracer, which is usually iodine or technetium, is given before either test and is absorbed by the thyroid gland from the blood stream. Ultrasonography may help to determine the extent of involvement and very rarely are any other diagnostic measures like CT Scan or MRI required.
What is the treatment modality following diagnosis?
The best way to treat hyperthyroidism is by converting it to hypothyrodism and then treat the patient for hypothyrodism! Having said this, the treatment in hyperthyroidism is usually, either to reduce the synthesis of the thyroid hormone by blocking the thyroid from making the thyroid hormone by giving some drugs, or by removing the thyroid, not by surgery, unless it is needed or when the women refuse RAI and can’t tolerate medication. Treating the patient with radio active iodine is the preferred mode of treatment really.
What is involved in removing the thyroid by using radio active iodine (RAI)?
Ablating the thyroid gland using RAI is a very safe and simple procedure. A radioactive iodine uptake (RAIU) test using technetium is done to measure the thyroid uptake in an individual suffering from hyperthyroidism. Based on this result we decide the amount of RAI to be given. These are usually in the form of capsules and only one capsule may be all that is required for most patients. Sometimes, should there be an under-dose, we give a second dose of RAI since it is better to over-treat than under-treat with no harmful consequence to the patient. Within two months of taking the RAI, the patients will become hypothyroid, following which we will treat them for hypothyroidism.
Some quarters claim that it is not adviseable to treat women in the reproductive ages with RAI, especially if they plan to become pregnant. Is this true?
No. It is 100% safe even given to women in this age group and women planning pregnancy. The only contra-indication for RAI is that it should not be given to pregnant women in any stage of pregnancy. But there is no problem at all using RAI on women planning to get pregnant because this does not affect fertility or lead to any kind of malformation in the foetus or give rise to leukemia in the child. RAI has been studied for over 60 years and all reports have returned safe. Over 2 million people have been treated with RAI and many of them were followed up to 60 years, and none has reported any adverse effects.
Why not anti-hyperthyroidism drugs?
Yes, some people do elect to give the temporary block of the thyroid hormone synthesis, in the form of anti hyperthyroidism drugs, thinking that the gland may come back to normal. This could happen only in about one-third of the cases. These drugs work initially for about a year or so but then the patients come back to square number one with the problem. Once you stop the drugs, the gland resumes its hyperfunction. So you have wasted your time taking these drugs. Moreover, these drugs are not safe during pregnancy and could have some serious side effects.
Side effects as in?
Liver toxicity and stomach irritation. The most serious side effect is Agranulocytosis, which means a lowered white blood cell (WBC) count in the blood (neutropenia). When WBC count is reduced significantly, the body’s ability to fight infection is lost and the patient could die from severe infection because she/he doesn’t have enough defenses to counter the infection. This is one of the known side effects of anti-hyperthyroidism drugs. However, if you recognize the symptoms of this early and withdraw the drug, the WBC count comes back to normal. Fortunately, this is a very, very rare instance.
At what point of time is surgery recommended?
Surgery is not the preferred way to deal with hyperthyroidism at all. Its role is very limited, It may be resorted to only during pregnancy when the woman cannot be given the anti-hyperthyroid drug or the RAI.
What is the prognosis for patients following treatment with RAI and then getting treated for hypothyroidism?
Prognosis is good and most patients lead normal lives with proper treatment.