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Conditions In Brief

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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

Definition

The thyroid gland is a butterfly-shaped gland in the front of the neck. It produces hormones that control metabolism. Hypothyroidism results when the thyroid gland doesn't produce enough thyroid hormone. The most common form of hypothyroidism is Hashimoto's thyroiditis.

Thyroid Gland

thyroid gland male
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Causes

Hashimoto's thyroiditis is an autoimmune disorder. The immune system produces antibodies that attack cells of the thyroid gland.

Hypothyroidism may also be caused by:

  • Congenital defects of the gland or how it works
  • Iatrogenic—occurs as the result of surgery or radiation therapy for thyroid cancer treatment
  • Iodine deficiency—rare in the US
  • Pituitary deficiency
  • Unknown reasons

Risk Factors

Hypothyroidism is more common in women, and in those aged 65 years and older. Other factors that may increase your risk of hypothyroidism include:

  • Family history of hypothyroidism
  • Autoimmune diseases, such as systemic lupus erythematosus, type 1 diabetes, or rheumatoid arthritis
  • Certain health conditions, such as infiltrative disorders, cancer, or infections
  • Surgery, radiation therapy, or radioablation in the neck region
  • Certain medications, such as lithium, iodine, or interleukins
  • Pituitary adenoma—benign tumor of the pituitary gland

Symptoms

You may not have symptoms of hypthyroidism. In those that have symptoms, hypothyroidism may cause:

Symptoms of severe or long-term hypothyroidism causes:

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include blood tests to check levels of thyroid stimulating hormone (TSH), and/or free T4. Your doctor may recommend other tests to rule out health conditions that are similar to hypothyroidism.

Treatment

Thyroid replacement therapy involves taking medications that replace the function of the thyroid gland. This therapy may also prevent cancer cell growth in people who had surgery or radiation treatment for thyroid cancer.

People with Hashimoto's thyroiditis are monitored as long as they have normal thyroid function and remain symptom-free. Once function decreases or symptoms appear, treatment is started with thyroid replacement therapy.

Prevention

There are no current guidelines to prevent hypothyroidism. If you are at high risk for developing hypothyroidism talk to your doctor about annual screening.

RESOURCES:

The American Thyroid Association

http://www.thyroid.org

Office on Women's Health

http://womenshealth.gov

CANADIAN RESOURCES:

Canadian Institute for Health

http://www.cihi.ca

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 Endocrinol Metab. 2005;90:4946-4954.

Hypothyroidism. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated November 12, 2013. Accessed November 25, 2013.

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.

Thyroid hormone treatment. American Thyroid Association website. Available at: http://www.thyroid.org/thyroid-hormone-treatment. Published June 4, 2012. Accessed November 25, 2013.

Last reviewed November 2013 by Kim Carmichael, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


 
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