The Facts

• Autoimmune disease is a disorder in which the immune system attacks healthy organs. In the case of autoimmune thyroid disease, the thyroid can become either underactive or overactive. Doctors are unsure what causes autoimmune disease, but it often runs in families.
  
  

Hashimoto's Thyroiditis

• With Hashimoto's Thyroiditis, also known as Hashimoto's Disease or chronic lymphocytic thyroiditis, the thyroid is attacked by the immune system and becomes underactive (or hypothyroid).
  
  

Graves' Disease

• The immune system also attacks the thyroid with Graves' Disease, but instead of becoming underactive, the thyroid begins to overproduce thyroid hormone.
  
  

Diagnosis

• Both Graves' Disease and Hashimoto's Thyroiditis are diagnosed by blood tests. An overabundance of thyroid stimulating hormone (TSH) in the blood means that the thyroid is underactive, while a low level of TSH means the thyroid is overactive.
  
  

Treatment

• Hashimoto's is treated with a thyroid hormone replacement pill while Graves' is treated with a thyroid suppressing medication, radioactive iodine therapy, or in severe cases, surgical removal of the thyroid.