What is Hypothyroidism?
Posted: Wednesday, October 29, 2008
by Bart Nieuwenhuijsen
http://www.reverta.com
Hypothyroidism is a condition in which the thyroid gland fails to produce sufficient amounts of thyroid hormones (thyroxine (T4) and triiodothyronine (T3)). Hypothyroidism is associated with a decreased metabolic rate. Over 5 million Americans suffer from this condition, and many of them don't even realize it. The thyroid gland can be found just below the larynx, in front of and to either side of the trachea (windpipe).
Thyroid hormones are essential for all tissues in the body, since thyroid hormones regulate every cell's metabolism. If thyroid output is insufficient, more thyroid stimulating hormone (TSH) is being produced by the pituitary gland (a small sized gland in the middle of the brain just below the hypothalamus). The continued stimulation of the thyroid gland could result in a greatly enlarged thyroid, called a thyroid goiter.
Hypothyroidism is frequently caused by thyroiditis, an inflammation of the thyroid gland. This is usually an auto immune reaction, whereby the patient's own immune system attacks the thyroid. This condition occurs in about 5% of women after giving birth. This form of post-partum thyroiditis first causes hyperthyroidism, an increased output of the thyroid gland. However, sometimes part of the thyroid is being destroyed by thyroiditis or by treatments to contain the overactive thyroid and the patient can develop lifelong hypothyroidism.
Hypothyroidism can also be caused when the pituitary gland produces an insufficient amount of thyroid stimulating hormone (TSH) to induce the thyroid to create more thyroid hormones. This condition is often caused by damage to the pituitary, either by a tumor, surgery or radiation. Even more rare is the condition in which the hypothalamus does not produce enough thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to create TSH.
What are the symptoms of hypothyroidism?
- fatigue
- goiter
- increased sleepiness
- increased sensitivity to cold temperatures
- muscle cramps and joint pain
- inability to lose weight despite dieting
- water retention
- brittle hair and fingernails
- dry itchy skin
- constipation
- depression
- decreased heart output
- disturbed menstrual cycle (late symptom)
- arteriosclerosis (late symptom): lack of thyroid hormones raises the level of blood lipids including cholesterol, which is associated with increased risk for atherosclerosis and arteriosclerosis.
- sluggish speech with a hoarse sounding voice (late symptom)
How is hypothyroidism diagnosed?
Doctors often look at the levels of TSH (produced by the pituitary) and both free and total thyroid hormones T3 and T4. Additional diagnostic tests include a 24 hour urine T3 test, serum cholesterol test, anti-thyroid antibody test and a test for anemia.
The author is senior editor for reverta.com. To learn more (including treatment options) visit hypothyroidism or thyroid supplement.
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