SINGAPORE - The thyroid - a butterfly-shaped gland in the front of the neck - produces hormones to regulate heart rate and maintain healthy skin. It also determines your metabolic rate as well as controls brain and bone development in infants.
When it is not in top form, it can make you less energetic, cause joint ache and weight gain, dry out your skin and even make you depressed.
When it is overworked and gives out too much hormones, it can affect your quality of sleep, cause your heart to race, and lead to weight loss.
Thyroid hormone imbalances often occur because of autoimmune disorders - when your own immune system mistakenly attacks healthy cells and tissues.
According to a Singapore General Hospital spokesperson, thyroid disorders usually crop up between the ages of 20 and 50 - and women are five times more likely than men to develop them.
"There are two main types of thyroid disorders - the development of nodules in the gland, and abnormal thyroid hormone levels," says Dr Samantha Yang from the Division of Endocrinology at the National University Hospital.
"In the former, benign nodules are harmless unless they are large enough to compress your neck. As for the latter, excessive levels cause hyperthyroidism, while insufficient levels cause hypothyroidism.
"Both types can lead to irregular periods and infertility. However, patients can become pregnant once they manage to control their thyroid hormone levels with the right medication for either one," she adds.
Hyperthyroidism occurs when the thyroid gland produces too much hormones.
Symptoms include an increased heart rate, diarrhoea, intolerance to heat, soft nails, increased skin dampness, lighter periods, unexplained weight loss, restlessness, insomnia, anxiety, nervousness and irritability.
It is mostly caused by Graves' Disease - a hereditary autoimmune disorder, where the body's antibodies attack the thyroid - that is common in women below 40.
The antibodies are produced by the brain to regulate thyroid hormone levels.
In Graves' Disease, they cause the thyroid to become overactive and also affect the eyes, causing red and swollen eye muscles.
That is why one of the more common symptoms of Graves' Disease is bulging eyes, explains Dr Yang. In severe cases, it could affect your vision.
Apart from Graves' Disease, another cause of hyperthyroidism is toxic nodular goiter. More common in women above 40, it involves an enlarged thyroid gland containing round growths called nodules.
These produce too much thyroid hormones. "It's not hereditary and the nodules are usually not cancerous. You can be treated with anti-thyroid medication or radioactive iodine to remove the hyperfunctioning thyroid tissues. Both treatments help to reduce thyroid hormone production," says Dr Yang, who adds that if you choose anti-thyroid medication, you will need to take it for life.
The medication is said to rarely have side effects, although some allergic reactions, like rashes and mouth ulcers, or liver dysfunction that could lead to jaundice or abdominal pain, have been noted.
Most patients need to be on anti-thyroid medication for at least 18 months. A further treatment period depends on how severe the problem is. If the nodules recur after you stop medication, you can opt for surgery to remove the thyroid gland, but you will need to be on lifelong thyroid hormone replacement therapy after that.
Sufferers of hyperthyroidism should avoid foods high in iodine. "Iodine produces thyroid hormones. When you consume a lot of it, the already-abnormal thyroid gland could produce even more hormones," Dr Yang points out. So reduce your intake of shellfish, seaweed, and even eggs.
This occurs when the thyroid gland doesn't produce enough hormones. Symptoms include a decreased heart rate, constipation, feeling cold all the time, brittle hair and nails, dry skin, heavy periods, unexplained weight gain, sluggishness, joint pain, forgetfulness and depression.
Women aged 40 and above have the highest risk, says Dr Yang.
Hypothyroidism is commonly caused by Hashimoto's Disease - a hereditary autoimmune condition in which your antibodies slowly destroy the thyroid gland.
This results in an underactive gland which can't produce enough hormones for the body. The treatment is straightforward: Lifelong hormone replacement therapy.
The medication is said to be free of side effects. In fact, an upside is that it helps patients shed the extra kilos they gained as a result of the disease.
As hypothyroidism can affect foetal brain and bone development, you should be reviewed by a doctor the moment you know you're pregnant. Your hormone replacement dosage will need to be adjusted to cater to your unborn child's developmental needs.
Can you die from a thyroid disorder?
Can you die from a thyroid disorder?
Thyroid disease can be fatal if it is not controlled and left to progress, says Dr Yang.
Both types of the disorder can lead to complications, as the heart, brain and internal system that regulates your body temperature won't be able to function properly. If you have benign thyroid nodule growths that are too large, they could compress your windpipe and threaten your life. They could also become cancerous and lead to thyroid cancer (women have a lower risk compared to men).
Hyperthyroidism: "My hands shook when I put on makeup…"
"I was diagnosed with hyperthyroidism at 25. I'd been getting such bad heart palpitations, I could actually see my chest rising and falling quickly. My hands also shook badly when I put on my makeup. Plus, my body always felt hot, my periods were irregular and I had bad mood swings.
"Although these symptoms made me physically uncomfortable, they didn't affect my work or lifestyle, so I didn't bother about them. It was only after a pre-employment check-up that I found out I had hyperthyroidism.
"I didn't know of anyone in my family with thyroid problems, and I was disheartened about having to be on lifelong medication. I've lived with hyperthyroidism for almost 11 years now. I go for annual eye checks to keep thyroid-related eye disease at bay, and avoid foods high in iodine. But I worry that as the years go by, my condition might worsen and lead to an early death. I also wonder about the long-term effects of my medication. Will it cause some other illness to kick in?"
- Rohana Haron, 36, educator
Hypothyroidism: "My periods became irregular and I was losing hair"
"I was 30 when I was diagnosed with hypothyroidism. Before that, I was always tired and didn't have the energy to go to work or to hang out with friends for too long.
"My periods became irregular, and my hair started falling out as well. At first, I thought it was my bad diet, too much work and too little rest. But when things persisted for about three months, I saw a doctor, who told me I had an underactive thyroid or hypothyroidism.
"When he told me the symptoms, everything clicked. It explained my recent weight gain - I'd put on 4kg within three months and couldn't shed the extra weight - and why I felt cold so easily. I was confused and upset that I had a lifelong illness, but what depressed me most was the possibility that the disease could hinder my desire to some day get pregnant and have kids.
"Although my medication has helped me cope with my condition, I've had a few disturbing episodes of memory loss. About five years ago, my short-term memory became significantly worse over a two-month period.
"At lunch one day, I was unable to focus on what my colleague was saying to me. I couldn't even figure out how to respond to her - it was like my entire brain had shut down.
"I panicked and called my doctor. He ran a battery of tests - including a red blood cell count - and found that I had slight anaemia (often associated with hypothyroidism), which could have led to the memory loss. After taking iron supplements for a week, my short-term memory and concentration problems went away."
- Leeza Tan, 40, administrator
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