Disease, Condition & InjuryHead & neck conditionsNeck

Hypothyroidism

(Hashimoto’s Thyroiditis; Underactive Thyroid)

Hypothyroidism – Definition

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.

Hypothyroidism – Causes

Hashimoto’s thyroiditis occurs when the immune system produces antibodies that attack cells of the thyroid gland. This causes chronic thyroid swelling and loss of function. Other causes include:

  • 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 United States)
  • Subacute thyroiditis — following a viral upper respiratory tract infection
  • Medical treatments — radiation to the head and neck or surgical removal of the thyroid gland (called subtotal thyroidectomy)
  • Medicines (eg, lithium, iodine, alpha-interferons, thiourea, amiodarone, interleukins)
  • Certain diseases (eg, cancer or infection)
  • Pituitary adenoma — benign tumor of the pituitary gland

Hypothyroidism – Risk Factors

These factors increase your chance of developing hypothyroidism:

Risk factors include:

  • Age: risk increases with age, especially over 65 years old
  • Sex: more common in females
  • Genetics: multiglandular autoimmune syndrome
  • Ethnicity: Caucasian, Hispanic
  • History of family members with hypothyroidism
  • History of other autoimmune diseases:
    • Pernicious anemia
    • Type 1 diabetes
    • Underactive adrenal or parathyroid glands
    • Rheumatoid arthritis
    • Lupus

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

Hypothyroidism – Symptoms

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

Hypothyroidism – Diagnosis

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 total T3
  • Antibodies that attack the thyroid gland

Hypothyroidism – Treatment

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:

  • Medicine to replace the thyroid hormones (eg, levothyroxine, triiodothyronine)
  • High-fiber diet to reduce constipation
  • Low-fat, low-calorie diet if you are overweight or obese

Hypothyroidism – Prevention

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:
    • Have Type 1 diabetes
    • Have infertility (females)
    • Take certain medicines

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