Hypothyroidism

Overview

Definition

The thyroid gland is a butterfly-shaped gland in the front of the neck. It makes hormones that control metabolism. Hypothyroidism is when the thyroid does not make enough thyroid hormone.

Thyroid Gland
thyroid gland male
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Causes

Hypothyroidism may be caused by damage or injury to the thyroid. This may happen with:

  • Disorder of the immune system
  • Congenital defects of the gland or how it works
  • Surgery, medical procedures, or radiation therapy for thyroid treatment

It may also be caused by:

  • Problems with pituitary glands that sends signal to the thyroid
  • Iodine deficiency—rare in the US, iodine is needed to make thyroid hormones

In some people, the cause may remain unknown.

Risk Factors

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

  • Family history of hypothyroidism
  • Recently gave birth, especially if you had hypothyroidism before
  • Surgery, radiation therapy, or radioablation in the neck region
  • Autoimmune diseases, such as systemic lupus erythematosus, celiac disease, type 1 diabetes, or rheumatoid arthritis

SymptomsandDiagnosis

Symptoms

Symptoms may not always appear. In those that have symptoms, hypothyroidism may cause:

  • Fatigue
  • Weakness
  • Coarse, brittle hair, and hair loss
  • Facial puffiness
  • Dry skin
  • Swollen hands or feet
  • Cold intolerance
  • Weight gain
  • Constipation
  • Achy feeling all over
  • Depression and irritability
  • Memory loss
  • Difficulty concentrating
  • Blurred vision
  • Menstrual abnormalities or infertility

Symptoms of severe or long-term hypothyroidism causes:

  • Slow heart rate
  • Depressed breathing
  • Hypothermia—low body temperature
  • Coma

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done.

A blood test may be done to check levels of thyroid stimulating hormone (TSH), and/or free T4. Other tests may be recommended to rule out health conditions that are similar to hypothyroidism.

Treatments

Treatment

Medicine can be used to make up for the missing thyroid hormones. The amount of medicine needed may change over time.

Prevention

There are no current guidelines to prevent hypothyroidism.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (Hashimoto's Thyroiditis; Underactive Thyroid)

RESOURCES

American Thyroid Association https://www.thyroid.org 

Office on Women's Health https://womenshealth.gov 

CANADIAN RESOURCES

Health Canada https://www.canada.ca 

Thyroid Foundation of Canada http://www.thyroid.ca 

References

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(8):4946-4954.

Hypothyroidism in adults. EBSCO DynaMed Plus website. Available at:  http://www.dynamed.com/topics/dmp~AN~T115914/Hypothyroidism-in-adults . Updated November 27, 2017. Accessed December 15, 2017.

Roberts CG, Ladenson PW. Hypothyroidism. Lancet. 2004;363(9411):793-803.

Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA. 2004;291(2):228-238.

Thyroid hormone treatment. American Thyroid Association website. Available at: https://www.thyroid.org/thyroid-hormone-treatment. Accessed December 15, 2017.