Hypothyroidism
En Español (Spanish Version)More InDepth Information on This ConditionHypothyroidism happens when 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. The most common form is Hashimoto's thyroiditis.
Thyroid Gland
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Hashimoto's thyroiditis occurs when the
immune system produces antibodies that attack cells of the thyroid gland. This causes chronic thyroid swelling and loss of function.
Other causes include:
- Idiopathic thyroid atrophy—destruction of thyroid tissue for unknown reasons
- Iodine deficiency—when a thyroid gland needs iodine to produce thyroid hormone (rare in the United States)
- Subacute thyroiditis—following a viral upper respiratory tract infection
-
Medical treatments—
radiation
to the head and neck or surgical removal of the thyroid gland (called subtotal
thyroidectomy
)
-
Medicines (eg,
lithium
, iodine, alpha-interferons, thiourea,
amiodarone
, interleukins)
-
Certain diseases (eg,
cancer
or infection)
- Pituitary adenoma
—benign tumor of the pituitary gland
These factors increase your chance of developing hypothyroidism:
Risk factors include:
- Age: risk increases with age, especially over 65 years old
- Sex: more common in females
- Genetics: multiglandular autoimmune syndrome
- Ethnicity: Caucasian, Hispanic
- History of family members with hypothyroidism
-
History of other autoimmune diseases:
Tell your doctor if you have any of these risk factors.
Years may pass before you notice symptoms.
Symptoms include:
Symptoms of severe or prolonged cases include:
-
Stupor or
coma
- Slow heart rate
- Depressed breathing
- Hypothermia
(low body temperature)
- Hoarseness
The doctor will ask about your symptoms and medical and family history, and perform a physical exam. To confirm the diagnosis,
blood tests
will be done, which include:
- Thyroid stimulating hormone
(TSH)
- Free T4 and total T3
- Antibodies that attack the thyroid gland
In the early stages of Hashimoto's thyroiditis, there is no specific treatment. But, in most cases, you will end up developing hypothyroidism. Treatment includes:
To help reduce your chance of getting hypothyroidism, take the following steps:
- Get a screening test every five years if you are 50 years old or older.
-
Get regular screenings if you:
The American Thyroid Association
Canadian Institute for Health
Thyroid Foundation of Canada
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.
Braunwald E.
Harrison's Principles of Internal Medicine
.
15th ed. New York, NY: McGraw Hill; 2001.
Escobar-Morreale HF, Botella-Carretero JI, Escobar del Rey F, et al. Treatment of hypothyroidism with combinations of levothyroxine plus liothyronine.
J Clin Endocrinol Metab
. 2005;90:4946-4954.
Roberts CG, Ladenson PW. Hypothyroidism.
Lancet
. 2004;363:793-803.
Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management
JAMA
. 2004;291:228-238.
Last Reviewed September 2011