Hashimoto's thyroiditis, also known as Hashimoto's Disease or chronic lymphocytic thyroiditis, is an autoimmune disease in which the body's immune system attacks the thyroid gland. Hashimoto's thyroiditis was the first ever recognized autoimmune disease.
Hashimoto's thyroiditis is the most common cause of primary hypothyroidism in North America and Europe. According to the U.S. National Library of Medicine1, it affects between 0.1% and 5% of adults in Western countries.
The American Association of Clinical Endocrinologists2 says that about 14 million Americans are affected by Hashimoto's thyroiditis. It is seven times more common in females than males. It is most prevalent among people aged between 45 and 65 years.
Hashimoto's thyroiditis is less common among children. However, in areas where iodine is a dietary scarcity, a significant proportion of children can develop the disease.
Hashimoto's disease is a major cause of goiter (a non-cancerous enlargement of the thyroid gland).
What are the signs and symptoms of Hashimoto's thyroiditis?
Hashimoto's thyroiditis develops gradually over several years, causing progressive thyroid damage along the way. The patient's levels of thyroid hormones gradually decrease.
Most of signs and symptoms are those of a person with an underactive thyroid, and may include some of the following symptoms:
- Abnormal sensitivity to cold temperatures
- Blood cholesterol levels rise
- Difficulty concentrating
- Dry skin
- Enlarged neck
- Face may appear swollen, puffed up
- General tiredness
- In females, menstruation is prolonged and abnormally bloody
- Muscle pains
- Pale skin
- Stiffness, especially the hands and feet
- Voice becomes hoarse
- Weight gain which does not appear to be the result of overeating
People with hypothyroidism do not all have the same set of symptoms. If you have a hoarse voice, constipation, a puffy and pale face, dry skin, and feel generally tired for no clear reason, you should see your doctor.
What are the causes of Hashimoto's thyroiditis?
Hashimoto's thyroiditis is an autoimmune disease. The patient's own immune system creates antibodies that attack and damage the thyroid gland.
Our immune system is designed to protect us against harmful invaders, such as viruses, bacteria, parasites and fungi. In patents with Hashimoto's thyroiditis, their immune system mistakenly recognizes normal thyroid gland cells as harmful, foreign tissue and attacks them.
Experts are not sure why the immune system becomes activated in such a way. Some suggest that perhaps a virus or bacterium may play or role, maybe a genetic fault, or possibly a combination. So far, none of these environmental or genetic factors have been compellingly proven to be the cause of Hashimoto's thyroiditis.
Diagnosing Hashimoto's thyroiditis
A significant number of patients with Hashimoto's thyroiditis are misdiagnosed with chronic fatigue syndrome, depression, fibromyalgia, an anxiety disorder, PMS (pre-menstrual syndrome) or cyclothymia. This is because during the early stages of hypothyroidism symptoms are relatively non-specific.
A doctor who is experienced and trained in diagnosing and treating thyroid diseases, such as an endocrinologist, can detect goiter during a physical examination, as well as carefully checking and identifying hallmark symptoms of hypothyroidism.
During the early stages of the disease, an endocrinologist is much more likely to diagnose Hashimoto's thyroiditis accurately than a primary care physician (general practitioner, GP). However, during the early stage a patient is more likely to see a GP first.
If the patient is feeling progressively tired, has pale and/or dry skin, a hoarse voice and constipation, the doctor will order some diagnostic tests.
Diagnostic tests may include:
- T4 (thyroxine) test - thyroxine is a hormone produced by the thyroid gland. This blood test measures how much thyroxine there is in the blood. If levels are low it means there could be something wrong with the thyroid gland.
- Serum TSH test - TSH stands for thyroid-stimulating hormone (thyrotropin). If blood levels of TSH are high, this is the most accurate indicator of hypothyroidism. TSH is produced in the pituitary gland. When the thyroid gland does not produce enough thyroid hormone blood levels of TSH rise.
If TSH levels are normal hypothyroidism is ruled out.
- Antithyroid antibody test - According to the American Association of Clinical Endocrinologists3, "increased antithyroid antibodies provide the most specific laboratory evidence of Hashimoto's thyroiditis." However, it also warns that the antibodies are not present in all cases.
Hashimoto's disease can sometimes change the results of total cholesterol, serum sodium, serum prolactin and complete blood count.
Doctors will not usually order imaging studies.
What are the treatment options for Hashimoto's thyroiditis
If the patient is diagnosed with Hashimoto's thyroiditis but thyroid hormone levels are normal and there is no goiter (swelling of the thyroid gland), the doctor will usually recommend watchful waiting.
Patients who require treatment will usually need to be treated for life.
Synthetic hormone treatment
For patients with goiter or hypothyroidism, thyroid hormone therapy is required.
The patient needs to take one tablet of levothyroxine each day. People with an underlying heart disease or severe hypothyroidism start off on a low dose which is gradually increased.
The treatment may take a few months before any improvements in symptoms are noticed.
There may be some hair loss during the first few months of treatment. This effect is temporary.
The patient will need to have periodical laboratory tests, the results of which decide whether doses require adjustments. The human body is extremely sensitive to even small alterations in thyroid hormone levels.
Drug interactions - some medications and supplements may interfere with levothyroxine absorption. Some foods may affect absorption as well, including soy products or very high fiber foods.
The following medications and supplements may interfere with proper levothyroxine absorption: