The infinite variations of thyroid disease – includes related information – Cover Story
Together with other glans in the endocrine system, the thyroid regulates and integrates the body’s metabolic activities. The hormones work like chemical messengers that act on every cell of the human body.[Publishers’ note: The following in-depth study is based on interviews with patients and medical experts in the specialized field of thyroid disorders and current medical literature and scientific research.]
Q: Which hormones does the thyroid produce?
A: It produces thyroxine, a compound of iodine and the amino acid tyrosine. Most of the iodine in the body is stored in the thyroid gland. A feed-back mechanism controls the release of thyroxine into the bloodstream.
Q: How does thyroxine affect bodily function?
A: Thyroxine accelerates the release of energy in the tissues. It derives its energy from combustion with glucose. With the accelerated combustion, breathing and circulation of blood are increased to meet the demand for oxygen; bodily and mental — activity are stimulated. The body temperature rises.
If thyroxine flow is normal, the thyroid remains balanced. If it drops, the thyroid fails to maintain its energy. Too much thyroxine can create hyperthyroidism.
Q: Cretinism is associated with the failure of the thyroid gland to develop normally. The disorder has been linked to thyroid malfunction. How?
A: Cretinism, or infantile myzedema, is a condition created by a lack of thyroid secretion during the birth process that retards the gland from developing. The newborn with this condition is usually a normal baby, presumably because the fetus was able to use thyroxine from the mother’s thyroid. After birth the child’s mental and physical functions begin to degenerate.
If the infant is given thyroxine soon after birth, however, there is a possibility that normal development can be achieved.
Q: Goiter has always been associated with thyroid disorder. Is the cause a faulty thyroid? To what extent is diet also related?
A: Iodine is the thyroid’s most important source of raw material necessary for proper functioning. Deprived of the element, the thyroid is forced to stimulate the production of thyroxine. Consequently, the effort causes overgrowth (goiter formation).
Where the soil lacks iodine, thyroid deficiency and goiter are prevalent. Iodine regulates the body’s metabolization of food (the process of converting food into energy), and, when taken as a medication, must be carefully prescribed; an overdose can have serious consequences.
Iodized salt, the product of iodine added to ordinary salt, has reduced goiter cases considerably in the United States and other countries. Consumers who seek other nutritional sources of the mineral because of their concerns about excessive salt consumption have not, as yet, found a proven substitute.
Claims have been made for kelp, a mineral from the sea that constitutes a large part of the Japanese diet. While thyroid disease is seldom experienced in Japan, any connection between its rarity and kelp consumption has yet to be substantiated.
In Austria, researchers have studied Vitamin A and carotene levels in 190 patients with thyroid disease. Serum levels of carotene were found to be decreased only in those patients with hypothyroidism, but serum levels of Vitamin A were significantly decreased in both the hypothyroid and the hyperthyroid patients.
These findings seem to indicate that Vitamin A helps keep the thyroid on an even keel (Smolle, Wawschin, Hayn et al., “Serum Levels of Vitamin A and Carotene in Thyroid Disease,” Acta Med. Aust.).
Q: Besides the formation of a goiter) are there other characteristics of an overactive thyroid?
A: Medical science sometimes does not know why thyroid glands begin overworking.
The condition is known as hyper thyroidism.
Weight loss often occurs, and metabolism accelerates. Too much thyroid hormone in the body can also cause exhaustion, and patients are unable to relax.
Symptoms of an overactive thyroid include nervousness; excessive perspiration and intolerance of heat; insomnia; palpitations; increased hunger, thirst, and weight loss; bulging eyes; abdominal swelling; muscle weakness; and emotional instability.
Q: Should treatment be sought if symptoms of overactive thyroid are experienced?
A: Emergency treatment is called for if the individual experiences such symptoms as sudden fever, extreme muscle weakness, persistent restlessness, irregular heartbeat, tremors, or mental confusion. These may be symptomatic of a surge in thyroid hormones which can be life threatening.
Q: Underactivity of the thyroid gland seems to affect people of all ages; what are the underlying causes?
A: Hypothyroidism can follow hyperthyroidism, as the hyperactive thyroid gland in an exhaustive state may become underactive. The danger inherent in that condition is a severe slowing down of body functions. The patient is overwhelmed by feelings of weariness, exhaustion, aches, pains, and reduced pulse rate.
Patients also begin to eat less (but always gain weight). Cold and heat are felt more acutely. Hair becomes thinner and drier. Skin becomes dry and thickens. Puffy tissue also accumulates on the vocal cords. The voice may deepen abnormally. Hearing loss may ensue. Women develop heavy, prolonged menstrual periods. Both men and women may lose interest in sexual activity.
Hypothyroidism is not a rare condition. While it is seldom seen at birth, it can develop for no apparent reason. Treatment consists of a regimen of synthetic thyroid hormones.
Q: Are thyroid nodules serious? Should they always be removed?
A: A thyroid nodule usually shows up as a swelling in the front part of the neck. Nodules can be painful and large enough to make swallowing and breathing difficult. Their origins are not known.
If the nodules are small, the doctor may advise leaving them alone. A thyroid scan may reveal cancer. Removal of the gland surgically will require treatment with thyroxine tablets to compensate for loss of the natural hormone.
Q: What are the functions of the parathyroid glands?
A: There are four parathyroid glands on the edge of the thyroid. They produce hormones that work with calcitonin (made by the thyroid gland) and are important in controlling the level of calcium in the blood. Calcium, among other functions, regulates blood clotting and the functioning of the nervous and muscle systems.
Q: If hormonal treatment for disease is not successful, is surgery an option?
A: Before a patient is hospitalized for surgery, there are several diagnostic tests performed. Because the thyroid’s primary function is to control metabolism, many surgeons recommend removal of a faulty thyroid gland or part of the gland. If medical therapy and surgery are not successful, radioactive iodine is sometimes used.
Surgery is also used to eliminate an enlarged thyroid-gland (goiter) or cancerous tumors of the thyroid.
Q: Does the thyroid degenerate with aging?
A: Thyroid function in the elderly varies. Many individuals never notice the gradual decrease in the rate of hormone production. Others accept the symptoms of thyroid degradation as a natural consequence of growing older. The normal thyroid, after age 70, contains numerous nodules. The changes are of minor significance and do not indicate thyroid dysfunction, nor do they require treatment.
Because thyroid function can be affected by physical stress, starvation, or depression, many elderly become vulnerable to hypothyroidism from lifestyle rather than from normal aging.
Diabetes in well-controlled patients usually does not affect thyroid function. Medications and drugs, often used habitually by the elderly, can contribute to thyroid abnormalities.
Phenobarbital, Dilantin, and Reserpine (an antihypertensive medication) have been known to accelerate thyroid dysfunction in the elderly.
Consist of two lobes, one on either side of Adam’s apple, joined at their lower ends by a bridge of glandular tissue across the upper part of the trachea.
A hormone made by the thyroid gland that controls the rate at which metabolism takes place (the more secreted, the faster your metabolism runs). Thyroxine containes iodine.
Each one about the size of a pearl, these glands are located on the thyroid gland. They produce parathyroid hormones.
Inflammation of the thyroid due to a virus infection.
Also known as Graves’ disease, toxic goiter. An overactive thyroid condition.
Also known as Hashimoto’s disease. An underactive thyroid condition.
A form of retardation caused by a thyroid deficiency during pregnancy. Early treatment has been known to restore the condition to normal.
An enlargement of the thyroid gland. Simple goiter is caused by lack of iodine in the diet.
References and interviews: DeGroot, Larso, Refeloof, and Stanbury, The Thyroid and Its Diseases, Fifth Edition. Published by Wiley Medical; Professional Guide to Diseases. Published by Intermed Communications; The Merck Manual, Sixteenth Edition; J.C. Mortensen, Journal of Clinical Endocrinology; Scientific American Medicine; J.D. Fachie, Henry Ford Hospital; Ruth Winter, M.S., Medicines in Food; Frank H. Netter, M.D., Endocrine System; Kelly D. Davis, M.D.; John C. Morris, MD.; William H. Snyd, M.D.; Alastair J. Wood, M.D.; Russell T. Joffe, M.D.; Shigenobu Nagataki; Duncan C. Thomas M.D.
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