Wednesday, May 20, 2009

STI: Little gland, big impact

May 21, 2009

Little gland, big impact

The first International Thyroid Awareness week from May 25 to 31 throws the spotlight on thyroid disorders, which tend to affect Asians more. POON CHIAN HUI reports


Many things can go wrong when the thyroid gland malfunctions.


At the heart of thyroid disorders is the hormone thyroxine, produced by the butterfly-shaped gland that sits in front of the windpipe.


Thyroxine is akin to the 'energy source' for all bodily functions, said Dr Luke Tan, a consultant ear, nose and throat - head and neck surgeon at Gleneagles Hospital.


Dr Tan has a special interest in thyroid surgery.


'It affects general well-being, energy levels, body weight, mood, can cause menstrual irregularities and skin and hair changes, among other things,' he said.


Abnormal hormone production can result in two conditions.


Hyperthyroidism results when excessive amounts of thyroid hormones are produced. Also known as Grave's disease, this is the most common thyroid disorder in Singapore, said Dr Daphne Khoo, head and senior consultant at the department of endocrinology at Singapore General Hospital.


'Women between 20 and 40 years old are especially affected by Grave's disease,' said Dr Khoo. Symptoms include weight loss with increased appetite, breathlessness, muscle weakness, moodiness, fast heart rate and irregular periods. Some may also experience more visible signs like puffy eyelids and protruding eyes.


'It really bothers the patient when the eyes are affected,' she said. 'One can go blind due to increased eye pressure, and women get very upset over their 'fish-eye' appearance.'


However, for hypothyroidism - caused by an underactive thyroid gland - the signs are more subtle.


Common effects are weight gain, constipation, increased cholesterol level and, in women, very heavy periods. Other than symptoms being fairly innocuous, the progression of the disease can be quite gradual as well.


However, this does not mean that it should be taken less seriously. Early screening and treatment is important because both thyroid disorders can be life-threatening, said Dr Khoo.


For instance, in pregnant women, excessive thyroid hormones increase the risk of miscarriages. Insufficient hormones, however, can cause the baby to have brain development problems, like a lower IQ, as thyroid hormones are heavily involved in growth and development.


In general, thyroid hormone disorders hit women harder - about 80 per cent of cases involve women, said Dr Khoo - although Oriental (Chinese, Japanese and Korean) men may suffer a rare complication called thyrotoxic periodic paralysis, which normally renders their limbs immobile. An injection of potassium ions can correct the temporary paralysis.


Another class of problems arise from tumour growth. Dr Tan said: 'It appears as a mass in the lower part of the neck, which typically moves up when the person swallows.' Tumours that are cancerous will have to be removed by surgery. Benign ones are removed if the person encounters breathing or swallowing problems, he said.


Although thyroid cancer is less common than hormone-related problems, the lack of symptoms means that it usually goes undetected by the person, he said.


According to the American Thyroid Association, thyroid problems are three times higher in Asians compared to other ethnic groups. Dr Khoo estimates that up to 4 per cent of the population in Singapore have some kind of thyroid disorder.


However, one should not panic when faced with a thyroid problem.


'Although it can be a lifelong problem, as long as you take your medication, it can be managed well,' said Dr Khoo.


In addition to medication to regulate hormone levels, surgery and radioactive iodine therapy can be used to treat cancer and also to reduce the size of the thyroid gland for hyperthyroidism sufferers.

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