In underdeveloped countries, a chronic lack of iodine in a diet (the thyroid needs iodine to produce thyroid hormones) is a major cause of hypothyroidism. Due to the addition of iodine to table salt and iodine-laced disinfectants used on cows' udders, this cause of hypothyroidism has disappeared in the U.S.
Hypothyroidism is the condition in which the thyroid is underactive (for example, it is producing an insufficient amount of thyroid hormones). Hypothyroidism is the most common thyroid disorder. Severe hypothyroidism can lead to a rare condition called myxedema, characterized by dry, thickened skin, coarse facial features, confusion, decreased body temperature, decreased heart rate, and, possibly, coma.
The most common cause of hypothyroidism is the body's immune reaction to itself, producing antibodies against the thyroid gland. One such autoimmune disorder is called Hashimoto's thyroiditis, an inflammation of the thyroid gland. Other causes include treatment of hyperthyroidism such as radioactive iodine treatment or surgery.
Symptoms of hypothyroidism are usually very subtle and gradual and may be mistaken for symptoms of depression. The following are the most common symptoms of hypothyroidism. However, each individual may experience symptoms differently. Symptoms may include:
- Dull facial expressions
- Cold intolerance
- Hoarse voice
- Slow speech
- Droopy eyelids
- Puffy and swollen face
- Weight gain
- Sparse, coarse, and dry hair
- Coarse, dry, and thickened skin
- Carpal tunnel syndrome (hand tingling or pain)
- Slow pulse
- Muscle cramps
- Sides of eyebrows thin or fall out
- Increased or irregular menstrual flow in women
Untreated hypothyroidism may lead to anemia, low body temperature, and heart failure.
The symptoms of hypothyroidism may resemble other conditions or medical problems. Always consult your doctor for a diagnosis. A condition called secondary hypothyroidism sometimes occurs as a result of a failing pituitary gland. When the pituitary gland fails, it no longer stimulates the thyroid to produce thyroid hormones.
In addition to a complete medical history and medical examination, diagnostic procedures for hypothyroidism may include blood tests to measure levels of thyroid hormones and the thyroid-stimulating hormones produced by the pituitary gland.
The goal of treatment is to restore the circulating thyroid hormone level back to normal.
Treatment may include prescription of thyroid hormones to replace the deficient hormones. Dosage of thyroid hormone may need to be increased or decreased over the years. Routine testing of the thyroid hormone levels in the blood is necessary to ensure that the patient is taking the correct dose of thyroid hormone replacement. A patient usually takes thyroid hormones for the rest of his or her life.
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Last reviewed: 4/30/2013