Hypothyroidism is a disease in which the thyroid gland does not produce enough thyroid hormone. The thyroid gland is a butterfly-shaped gland in the front of the neck. It produces hormones that control metabolism. Hashimoto's thyroiditis is the most common cause of hypothyroidism.
Causes
Hashimoto's thyroiditis is an autoimmune disease. Your own immune system creates antibodies that attack the cells of the thyroid gland. This causes chronic thyroid inflammation and loss of thyroid function. Other causes of hypothyroidism include:
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Idiopathic thyroid atrophy – destruction of thyroid tissue for unknown reasons
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Iodine deficiency – when a thyroid gland needs iodine to produce thyroid hormone (rare in the United States)
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Subacute thyroiditis – following a viral upper respiratory tract infection
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Medical treatments – radiation to the neck or surgical removal of part of the thyroid gland (called subtotal thyroidectomy)
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Medications (lithium, iodine, alpha-interferons, thiourea, amiodarone, interleukins)
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Infiltrative disease (eg, cancer or infection)
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Pituitary adenoma – benign tumor of the pituitary gland
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition.
Risk factors include:
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Age: risk increases with age, especially over 65 years old
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Sex: female
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Genetics: multiglandular autoimmune syndrome
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Ethnicity: Caucasian
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History of family members with hypothyroidism
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History of other autoimmune diseases:
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Symptoms
Symptoms develop gradually, and they may go unnoticed for years.
Symptoms include:
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Fatigue
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Weakness
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Coarse, brittle hair; hair loss
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Facial puffiness
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Dry skin
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Swollen hands or feet
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Cold intolerance
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Weight gain
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Constipation
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Achy feeling all over
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Depression and irritability
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Memory loss
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Menstrual abnormalities or infertility
Symptoms of severe or prolonged cases include:
Diagnosis
The doctor will ask about your symptoms and medical/family history, and perform a physical exam. Blood tests will be done to confirm the diagnosis, which include thyroid stimulating hormone (TSH), free T4 and free T3, and antibodies that attack the thyroid gland.
Treatment
In the early stages of Hashimoto's thyroiditis, there is no specific treatment. However, most people with Hashimoto's thyroiditis eventually develop hypothyroidism. At that point, you will need to start taking medication (levothyroxine and/or triiodothyronine) that replaces the thyroid hormone(s) your thyroid is not producing. You will have to take this medication indefinitely.
To reduce the discomfort from constipation, you will be asked to eat a high-fiber diet. If you are overweight or obese, you will be given a low-fat and low-calorie diet.
Prevention
Individuals over 50 years old should have a screening test (TSH) every five years. Individuals with any of the following are at higher risk of getting hypothyroidism and should be regularly screened:
RESOURCES:
The American Thyroid Association
http://www.thyroid.org
Medline Plus
http://medlineplus.gov/
CANADIAN RESOURCES
Canadian Institute for Health
http://www.cihi.ca/cihiweb/dispPage.jsp?cw_page=home_e
Thyroid Foundation of Canada
http://www.thyroid.ca
References:
American Association of Clinical Endocrinologists. AACE medical guidelines for clinical practice for the evaluation and treatment of hyperthyroidism and hypothyroidism. Endocrine Practice. 2002; 8:457-469.
Escobar-Morreale HF, Botella-Carretero JI, Escobar del Rey F, et al. Treatment of hypothyroidism with combinations of levothyroxine plus liothyronine. J Clin Endorinol Metab. 2005;90:4946-54.
Harrison's Principles of Internal Medicine. 15th ed.McGraw Hill; 2001.
Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management JAMA. 2004;291:228-238.
