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

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:

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.

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.