What is a goiter? How common is it in the Philippines? What causes this condition? How is it treated? --orly_ email@example.com
Goiter simply refers to an enlarged thyroid gland--a small, butterfly-shaped organ that straddles our windpipe (trachea) just below our Adam's apple. The thyroid gland produces hormones that regulate the way our body uses or produces fats, carbohydrates, and proteins and helps control our body temperature and heart rate.
Normally, the thyroid cannot be felt or seen except in very thin people, but when enlarged, it presents as a visible and palpable swelling on the neck called goiter.
Goiter is highly prevalent in the Philippines
Goiter affects only five percent of the world's population, but among Filipinos, the 2007 figures released by the Food and Nutrition Research Institute (FNRI) showed that close to eight percent have goiters, with the highest prevalence rate occurring in Bicol (12 percent), Eastern Visayas (11.4 percent), Metro Manila (9.7 percent), and Cagayan Valley (8.5 percent). A more recent (2012) survey by a working group of the Philippine Society of Endocrinology and Metabolism (PSEM) revealed that 8.9 percent of Filipinos have a goiter.
What causes goiter?
There are a variety of conditions that can give rise to a goiter. In the Philippines, the most common is a diet that is deficient in iodine, a trace element that we source from the food we eat. After being absorbed into our bloodstream by our intestine, iodine is collected by our thyroid gland because it is needed in the production of thyroid hormones. Lack of iodine in the diet forces the thyroid gland to work harder to be able to collect iodine, thus it enlarges. To eliminate this cause of goiter, our government has mandated that all salt sold in our markets be iodized.
Excess iodine intake (either from food or supplements) also produces goiter because in the presence of excess iodine, the thyroid is stimulated to produce more than the usual amount of thyroid hormones, a condition called hyperthyroidism and becomes bigger. Other causes of goiter include inflammation of the thyroid gland (thyroiditis), intake of medications such as lithium or aminoglutethimide, and pregnancy.
There are also two autoimmune diseases that bring about goiter, Graves' disease and Hashimoto's disease. In Graves' disease, the number one cause of hyperthyroidism is that our immune system mistakenly attacks the thyroid gland, causing it to produce excess hormones. This overstimulation causes the thyroid to enlarge. In Hashimoto's disease, on the other hand, our immune system damages the thyroid so that it produces very little thyroid hormone. Sensing a low thyroid hormone level, the pituitary gland (an endocrine gland located in the brain) produces a hormone that stimulates the thyroid to produce more hormones, which then causes the gland to enlarge.
Treatment of Goiters
A goiter is not a medical problem and no intervention is necessary if the blood level and activity of the thyroid hormones is normal. It only becomes significant if it is associated with decrease (hypothyroidism), or increase (hyperthyroidism) production or the activity of thyroid hormones; becomes large enough to press on surrounding structures; or, is nodular (i.e., it contains lumps or nodules) as there is a strong association between thyroid nodules and thyroid cancer.
Incidentally, hypothyroidism or hyperthyroidism can occur even without a goiter. In the PSEM study, only half of Filipinos who have hyperthyroidism had goiters while only one in six to 10 of those with hypothyroidism and other conditions had enlarged thyroid gland.
There are three main modalities that are employed singly or in combination in the treatment of goiters: drugs, surgery, and radioiodine therapy.
The drugs are designed to normalize the thyroid hormone levels in the blood (i.e., to increase levels if they are high or decrease levels if they are low) and to control symptoms that are present.
Surgery, on the other hand, which involves removal of all or part of the thyroid gland, is employed if the goiter is large and causes difficulty in breathing or swallowing, or if it is nodular.
Radioactive iodine therapy, meanwhile, is used in some cases of goiters that are associated with a hyperactive thyroid gland. This treatment involves taking radioactive iodine orally.
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