Diseases of the Endocrine Glands - The thyroid gland

The thyroid gland is located in the front of the neck just above its base. Normal amounts of thyroxin , the hormone secreted by the thyroid, are necessary for the proper functioning of almost all bodily activities. When this hormone is deficient in infancy, growth and mental development are impaired and cretinism results.


In adulthood, a deficiency of thyroxin hormone is caused primarily by a lack of sufficient iodine in the diet or by auto-immune factors. In hypothyroidism , the disorder resulting from such a deficiency, the metabolic rate is slower than normal, the patient has no energy, his expression is dull, his skin is thick, and he has an intolerance to cold weather.

Treatment consists of increasing the amount of iodine in the diet if it is deficient or giving thyroid hormone medication. Normal metabolic functioning usually follows, especially if treatment is begun soon after the symptoms appear.


An excess amount of thyroid hormone secretion is called hyperthyroidism . It causes physical fatigue but mental alertness, a staring quality in the eyes, tremor of the hands, weight loss with increased appetite, rapid pulse, sweating, and intolerance to hot weather.

Long-term treatment is aimed at decreasing hormone production with the use of a special medicine that inhibits it. In some cases, part of the gland may be removed by surgery; in others, radiation treatment with radioactive iodine is effective.

Hyperthyroidism may recur long after successful treatment. Both hypothyroidism and hyperthyroidism are common disorders, especially in women.

Other Thyroid Disorders

Enlargement of part or all of the thyroid gland occurs fairly often. It may be a simple enlargement of the gland itself caused by the lack of iodine, as in goiter , or it may be caused by a tumor or a nonspecific inflammation. Goiter is often treated with thyroxin, but it is easily prevented altogether by the regular use of iodized table and cooking salt. Treatment of other problems varies, but surgery is usually recommended for a tumor, especially if the surrounding organs are being obstructed.

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