Hypothyroidism 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

thyroid gland male
© 2009 Nucleus Medical Art, Inc.


Hashimoto's thyroiditis occurs when:

  • Immune system produces antibodies that attack cells of the thyroid gland, causing chronic thyroid swelling and loss of function
  • Other causes:
    • 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 US)
    • Subacute thyroiditis—following a viral upper respiratory tract infection
    • Medical treatments— radiation]]> to the head and neck or surgical removal of part of the thyroid gland (called subtotal ]]>thyroidectomy]]> )
    • Medications (eg, ]]>lithium]]> , iodine, alpha-interferons, thiourea, ]]>amiodarone]]> , interleukins) ]]>
    • Certain diseases (eg, cancer]]> or infection)
    • ]]>Pituitary adenoma]]> —benign tumor of the pituitary gland


Risk Factors

These factors increase your chance of developing hypothyroidism:

Risk factors include:

Tell your doctor if you have any of these risk factors.



Years may pass before you notice symptoms.

Symptoms include:

  • Fatigue
  • Weakness
  • Coarse, brittle hair; 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 with concentration
  • Blurred vision
  • ]]>Menstrual abnormalities]]> or ]]>infertility]]>

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 free 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: