Graves Disease: An Oxymoron – Dr. Chiam Keng Hoong

Source: edusanjalbiochemist.blogspot.com

Source: edusanjalbiochemist.blogspot.com

You meet a few close-knit friends for a buffet lunch and they marvel at your supermodel figure. They envy your inability to gain a single pound despite your enormous appetite.

Your partner is clearly confounded by the fact that you are sweating profusely although it is a cool night. You have stripped to the bare minimum but are still flushed and hot. You have to run to the shower several times and let cold water gush over your body in order to cool down.

Anger and frustration pervades your sense of being each time things do not go according to plan. Close friends are avoiding you and gossip is going around the camp about how easily irritated and agitated you get.

People describe you as a person who could pierce anyone’s confidence just by staring at them with your bulging, unmoving eyes. You find that you get excessively nervous about trivial things. You have palpitations at rest and your heart refuses to calm down – thumping away like a drum in the middle of the night.

Do any of the above sound familiar? If you answered yes, you may have a condition called hyperthyroidism. Affecting mainly the female population by a ratio of 7:1, these symptoms are often insidious, chronic and progressive.

Hyperthyroidism occurs when the thyroid gland goes into overdrive and releases more than normal amounts of thyroid hormones. The hormones circulate throughout the body and elevate the activity of all organs as they play a major role in the body’s metabolism.

It is important to note that hyperthyroidism is merely a term describing symptoms linked with a hyperactive thyroid gland and not a diagnosis on its own. The most common cause of hyperthyroidism is Graves’ disease that, despite its name, does not imply that the prognosis and general outlook of the condition is a bleak one. An autoimmune disorder, Graves’ disease manifests when self-produced antibodies persistently stimulate the thyroid gland. In healthy people, these autoantibodies are absent or present in minimal amounts and do not cause hyperthyroidism.

As a general physician who is approached only when symptoms have become troubling, I find that most patients welcome the increased energy and appetite as they can achieve and maintain their ideal weight while eating whatever they desire. It is hardly unusual then that patients do not seek treatment until the symptoms are intolerable and social embarrassment from profuse sweating, tremors and behavioural changes materialises.

The myriad of signs and symptoms associated with hyperthyroidism is best categorized according to the affected organs, as in table 1.

Table 1: Signs and symptoms of hyperthyroidism

Organ Symptoms Signs
General Lethargy, heat intolerance, weight loss, increased appetite, restlessness, anxiety, irritability, insomnia Goiter (neck swelling), finger clubbing
Skin Excessive sweating Warm, moist skin
Nerves and muscles Shaking hands Tremors, weakness at shoulders and hips
Heart Palpitations, vague chest discomfort Irregular pulse, tachycardia
Lungs Breathlessness on exertion
Kidneys Increased urination, unquenchable thirst
Intestinal Loose stools
Eyes Double vision, tearing, eye discomfort or pain Protruding eyeballs
Reproductive Irregular and/or reduced menstruation

Initial assessment is usually by a general physician or medical officer at a primary care level before referral to a physician for further management. Having a loved one around during the consultation would be helpful in identifying important symptoms that require collaboration with another eyewitness. History taking and physical examination is aimed at eliciting the signs and symptoms described in table 1. Some of the signs differentiating Graves’ disease from other causes of hyperthyroidism are eye protrusion (A), pretibial myxoedema (B) and finger clubbing (C) as shown below.

Following referral to a physician, a panel of blood tests is done to confirm the diagnosis of hyperthyroidism as well as assess the severity of the illness and its complications. Specific tests like thyroid function test and thyroid autoantibody markers are done alongside common tests like complete blood count, liver function test, kidney function test, cholesterol and glucose level. An electrical recording (electrocardiogram) and ultrasound study (echocardiogram) of the heart are done to detect thyrotoxic cardiomyopathy, a complication of hyperthyroidism that could progress to heart failure. In tertiary settings, an ultrasound of the thyroid gland is also done to rule out other causes of hyperthyroidism like multinodular goiter or solitary toxic nodule. A diffusely smooth and enlarged thyroid gland is in keeping with Graves’ disease.

Conventional treatment of Graves’ disease is with oral anti-thyroid agents, radioiodine therapy and surgical removal of the thyroid gland. There are two anti-thyroid medications available in Malaysia – carbimazole and propylthiouracil. Close compliance and monitoring of side effects is required during treatment. The most worrying side effect is agranulocytosis, where the body fails to produce sufficient white blood cells that function as its main defense mechanism against infections. It is advisable to seek treatment urgently if you come down with a fever while taking anti-thyroid medications.

If anti-thyroid medications fail to normalise thyroid hormone levels or control the symptoms after 12 to 18 months, patients are advised for radioiodine therapy. It is a painless treatment where patients consume a small amount of translucent liquid that diminishes the function of the thyroid gland, rendering it inactive towards the autoantibodies. Patients are rarely subjected to surgical intervention, as radioiodine therapy is effective in curing Graves’ disease.

Radioiodine therapy and complete resection of the thyroid both result in irreversible termination of thyroid gland function. Patients will require life-long thyroid hormone replacement with levothyroxine and regular follow up consultations.

Current and future research is aimed at advancing modern therapy towards targeting the autoantibodies rather than the thyroid gland itself. It is hoped that with the advent of such treatment, the common fears and worries about radioiodine therapy can be eliminated. In the meantime, it is best to mention that patients should seek advice from doctors with regards to the different modalities of management of Graves’ disease.

Dr. Chiam Keng Hoong is an internal medicine physician and a MRCP holder. He currently works in Sabah.

References

  • Harrison’s Principles of Internal Medicine, 17th Edition

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