Hashimoto's thyroiditis (hypothyroidism)

Hashimoto's thyroiditis or Hashimoto's disease (also known as chronic lymphocytic thyroiditis) is an autoimmune disease affecting thyroid function, where the body's immune system creates antibodies that attack and inflame the thyroid.

Hashimoto's thyroiditis is the most common cause of hypothyroidism (or underactive thyroid or low thyroid) in the United States. Hypothyroidism is an endocrine disorder in which the thyroid gland does not produce enough thyroid hormone called T4 (thyroxine), which is used to help the body use energy as well help maintain function of the brain, heart, muscle, and other organs.

Signs and symptoms
Symptoms of an underactive thyroid due to Hashimoto's include:
 * Weight gain
 * Hair loss (or thinning)
 * Fatigue
 * Sensitivity to cold
 * Constipation
 * Joint and muscle pain
 * Excessive or prolonged menstrual bleeding
 * Depression

Cellular hypothyroidism
Some patients may exhibit Hashimoto's hypothyroid symptoms, yet display normal ranges in their thyroid blood tests. This could be an indication of “cellular or peripheral hypothyroidism”, where there's a deficiency at the cellular level. While thyroid hormone production may be functioning properly, the transportation of thyroid hormone into cells will be hindered if there is mitochondrial dysfunction.

Mitochondrial dysfunction has been implicated countless times, not only as a contributor to, but often cited as the immediate cause of ME/CFS symptoms.

Viral triggers of Hashimoto's
Viral infections are common triggers of Hashimoto's thyroiditis, and hypothyroidism. Epstein-Barr virus (EBV), Human Herpesvirus 6 (HHV-6) are perhaps two of the most common viral triggers for Hashimoto. Others include Herpes Simplex 1 & 2 (HSV), Cytomegalovirus (CMV), Enterovirus, and Parvovirus B19.

Studies linking viral infections to Hashimoto's & ME/CFS
Studies suggesting a viral trigger for Hashimoto's thyroiditis and autoimmune thyroiditis (AIT) that are also viruses commonly associated with ME/CFS.

Hashimoto's and sleep apnea
Hashimoto's thyroiditis (HT) and sleep apnea can both result in extreme fatigue. New evidence suggests a connection between Hashimoto's and obstructive sleep apnea (OSA). In fact, the association could be bi-directional, where either condition could potentially develop as a consequence of the other.

Hashimoto's HLA risk alleles
Variations in several human leukocyte antigen (HLA) complex family of genes have been studied as possible risk factors for Hashimoto thyroiditis. Associations have been found between Hashimoto's disease and the following HLA alleles:
 * C*07:04
 * DQB1*03:03
 * DRB1
 * DRB1*04:10

HLA risk alleles link ME/CFS and Hashimoto's
In a large 2020 study, CFS patients with Human Leukocyte Antigen (HLA) risk alleles (C*07:04 and DQB1*03:03) were found to share the following autoimmune diseases, ordered by frequency:
 * 1) Hashimoto's thyroiditis
 * 2) Psoriasis
 * 3) Rheumatoid arthritis
 * 4) Alopecia areata
 * 5) Crohn’s disease or ulcerative colitis

Diagnosis
Hashimoto's thyroiditis is usually diagnosed based on multiple examinations, often beginning with hypothyroid symptom evaluation. This can be accompanied by blood tests and ultrasound.

Blood tests indicating Hashimoto's disease include elevated levels of thyroperoxidase antibodies (TPO), and elevated levels of thyroid stimulating hormone (TSH). Other lab testing can include Thyroglobulin antibodies (Tg), Free thyroxine (T4), or Free triiodothyronine (T3).

This might be followed by an ultrasound to confirm an enlarged thyroid gland, and other features of Hashimoto's thyroiditis.

Learn more

 * Hashimoto's - Thyroid UK