Hashimoto’s Thyroiditis (Lymphocytic Thyroiditis)
The term “Thyroiditis” refers to “inflammation of the thyroid gland”. There are many possible causes of thyroiditis (see Thyroiditis brochure). Hashimoto’s thyroiditis, also known as chronic lymphocytic thyroiditis, is the most common cause of hypothyroidism in the United States. It is an autoimmune disorder involving chronic inflammation of the thyroid. The thyroid gland makes hormones that control virtually all of the body’s metabolic functions (how the body turns food into energy) and keep it working normally. Hashimoto’s thyroiditis is a type of autoimmune disease — your immune system doesn’t recognize your thyroid as your own and attacks it.
This condition tends to run in families. Over time, the ability of the thyroid gland to produce thyroid hormones often becomes impaired and leads to a gradual decline in function and eventually an underactive thyroid (Hypothyroidism). Hashimoto’s thyroiditis occurs most commonly in middle aged women, but can be seen at any age, and can also affect men and children.
What causes Hashimoto’s disease?
Researchers aren’t sure why some people develop autoimmune disorders such as Hashimoto’s disease. These disorders probably result from a combination of genes and an outside trigger, such as a virus.
In Hashimoto’s disease, your immune system makes antibodies that attack the thyroid gland. Large numbers of white blood cells called lymphocytes, which are part of the immune system, build up in the thyroid. Lymphocytes make the antibodies that start the autoimmune process.
Symptoms of Hashimoto’s thyroiditis
Because the condition usually progresses very slowly over many years, people with Hashimoto’s thyroiditis may not have any symptoms early on, even when the characteristic thyroid peroxidase (TPO) antibodies are detected in blood tests. TPO is an enzyme that plays a role in the production of thyroid hormones. If Hashimoto’s thyroiditis causes cell damage leading to low thyroid hormone levels, patients will eventually develop symptoms of hypothyroidism
- weight gain
- trouble tolerating cold
- joint and muscle pain
- constipation
- dry, thinning hair
- heavy or irregular menstrual periods and problems becoming pregnant
- depression
- memory problems
- a slowed heart rate
Who is most likely to develop Hashimoto’s disease?
Hashimoto’s disease:
- Is more common in women than men.
- Commonly appears between the ages of 30 and 50.
- Tends to run in families (hereditary).
- Is more likely to develop in people who have other autoimmune diseases, like certain liver conditions, B12 deficiency, gluten sensitivity, rheumatoid arthritis, type 1 diabetes, lupus and Addison’s disease (an adrenal gland condition).
How is Hashimoto’s thyroiditis diagnosed?
Hashimoto’s is typically diagnosed by a combination of your signs, symptoms, and blood tests. In many cases of Hashimoto’s disease, the thyroid may become enlarged and form a swelling in your neck called a goiter, which you may be able to see or feel. First, your doctor will review your health history, symptoms, and perform a physical exam to check for goiters. Next, your doctor will likely order blood tests to test your thyroid hormone function and antibodies.
- Thyroid Stimulating Hormone (TSH) Test
This standard hormone test looks at your thyroid stimulating hormone (TSH).6 TSH is made by the pituitary gland in your brain and it works by signaling your thyroid to produce the hormones your body needs. When your thyroid is under-functioning, your TSH level will usually be elevated because your pituitary gland is trying to prompt your thyroid gland to produce more hormones.
The typical normal range for TSH is 0.5–4.5 or 5.0 milli-international units per liter (mIU/L), but this can vary depending on the laboratory that’s doing the testing. If your TSH level falls under 0.5 mIU/L, this indicates that you have an overactive thyroid (hyperthyroidism). Numbers above the normal range, usually 5.0 mIU/L or higher, show that you may have hypothyroidism.
- Free T4 Test
Thyroxine, or T4, is the active thyroid hormone in the blood, and your doctor may measure the level of free T4 in your bloodstream to help confirm a Hashimoto’s thyroiditis diagnosis. Low levels of free T4 indicate some deficiency in thyroid hormone production, even if your TSH levels are normal.
- Anti-thyroid Antibodies Tests
Another blood test your doctor may order, especially if you have a goiter or subclinical hypothyroidism, looks for antibodies called thyroid peroxidase (TPO) antibodies. These antibodies attack the TPO enzymes found in your thyroid, gradually destroying it. If you have elevated levels, you likely have Hashimoto’s disease.9
That said, though the majority of people with Hashimoto’s disease—over 90 percent10—have elevated TPO antibody levels, this test alone isn’t a sign that you have the condition. Other forms of thyroiditis, such as silent thyroiditis or postpartum thyroiditis, may be responsible. Or you may be one of the more than one in 10 people who have the antibodies but normal TSH and free T4 levels.11
Having only the TPO antibodies present with normal TSH and free T4 levels means that your thyroid is functioning normally and you don’t have hypothyroidism, but it does mean that you may have Hashimoto’s disease. Remember that Hashimoto’s doesn’t always cause hypothyroidism.
- Imaging
In certain instances, like when you don’t have the TPO antibodies in your blood but your doctor still thinks you could have Hashimoto’s, he or she may order a thyroid ultrasound.
- Differential Diagnoses
Almost all instances of primary and subclinical hypothyroidism in the United States are caused by Hashimoto’s disease, so if your TSH level is above the normal range, Hashimoto’s is most likely the reason. However, occasionally an elevated TSH is an indicator of a different problem, so your doctor will rule out other possible conditions as well.
- TSH Resistance
- Thyroid Hormone Resistance
- Recovery From Another Illness Examples of these non-thyroidal illnesses include: Gastrointestinal diseases, lung, heart, kidney diseases, metabolic disorders, inflammatory diseases, surgery, trauma, bone marrow transplantation and heart attack
- TSH-Secreting Pituitary Adenoma
- Adrenal Insufficiency
References
https://www.niddk.nih.gov/health-information/endocrine-diseases/hashimotos-disease
https://my.clevelandclinic.org/health/diseases/17665-hashimotos-disease/outlook–prognosis
https://www.verywellhealth.com/how-to-test-for-hashimotos-disease-4159884
