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Hypothyroidism: Symptoms and Risk Factors

Hypothyroidism is a condition in which the thyroid gland fails to produce enough of the hormones that are essential for a wide variety of functions in the body, including proper cardiac, nerve, gastrointestinal, and psychologic function.

Hypothyroidism affects about five million Americans. The most common cause worldwide is iodine deficiency. However, in the United States, where iodized salt is commonly used, most cases are due to an autoimmune disease called Hashimoto’s thyroiditis. Other causes include drugs (e.g., lithium and amiodarone), genetic factors, neck surgery, and radiation therapy.

Myxedema coma is a life–threatening complication of hypothyroidism that is marked by confusion, disorientation, low blood pressure, low body temperature, decreased breathing rate, and, though rarely, coma. Causes of myxedema coma in patients with hypothyroidism can include infection, heart attack, stroke, trauma (including surgery and burns), low blood sugar, electrolyte disturbances, severe bleeding, noncompliance with thyroid medications, and various drugs (e.g., beta–blockers, sedatives, narcotics, and phenothiazine antipsychotic drugs). 


Symptoms can be subtle and nonspecific, including weakness, fatigue, and weight gain. Chronic or severe disease can result in:

  • Goiter (a swelling at the base of the neck)
  • Dull facial expression
  • Drooping eyelids
  • Hoarse speech
  • Thinning or dry, brittle hair
  • Dry skin
  • Myxedema (swelling of the skin)
  • Menstrual disorders
  • Slow heart rate
  • Constipation
  • Depression
  • Tingling
  • Decreased coordination
  • Anemia

Risk Factors

  • Gender: The majority of cases occur in women.
  • Age: Risk of hypothyroidism increases with age.
  • Genetics: Hypothyroidism is associated with several gene mutations.
  • Obesity


Hypothyroidism: Diagnosis and Treatment >>