The thyroid is a small, butterfly-shaped gland in the front of your neck. In people with Hashimoto’s disease
the immune system makes antibodies that attack the thyroid gland
large numbers of white blood cells, which are part of the immune system, build up in the thyroid
the thyroid becomes damaged and can’t make enough thyroid hormones
Thyroid hormones control how your body uses energy, so they affect nearly every organ in your body—even the way your heart beats.
Overview
Hashimoto's disease is an autoimmune disorder affecting the thyroid gland. The thyroid is a butterfly-shaped gland located at the base of the neck just below the Adam's apple. The thyroid produces hormones that help regulate many functions in the body.
An autoimmune disorder is an illness caused by the immune system attacking healthy tissues. In Hashimoto's disease, immune-system cells lead to the death of the thyroid's hormone-producing cells. The disease usually results in a decline in hormone production (hypothyroidism).
Although anyone can develop Hashimoto's disease, it's most common among middle-aged women. The primary treatment is thyroid hormone replacement.
Hashimoto's disease is also known as Hashimoto's thyroiditis, chronic lymphocytic thyroiditis and chronic autoimmune thyroiditis.
symptoms
Some people may not have any symptoms at first. As the disease slowly progresses, the thyroid gland becomes enlarged (a condition called a goiter). A goiter is a common first sign of Hashimoto’s disease. A goiter is painless, but can create a feeling of fullness in the throat, and can make the front of your neck look swollen.
Other symptoms of Hashimoto’s disease that develop over time include:
- Tiredness (fatigue).
- Weight gain.
- Feeling cold.
- Joint stiffness and muscle pain.
- Constipation (trouble having a bowel movement).
- Depression.
- Puffy eyes/face.
- Dry skin.
- Thinning hair/hair loss.
- Heavy or irregular periods.
- Difficulty becoming pregnant.
- Memory problems/difficulty thinking or concentrating.
- Slow heartbeat.
Causes
The exact cause of Hashimoto's is not known, but many factors are believed to play a role. They include:
Genes. People who get Hashimoto's often have family members who have thyroid disease or other autoimmune diseases. This suggests a genetic component to the disease.
Hormones. Hashimoto's affects about seven times as many women as men, suggesting that sex hormones may play a role. Furthermore, some women have thyroid problems during the first year after having a baby. Although the problem usually goes away, as many as 20% of these women develop Hashimoto's years later.
Excessive iodine. Research suggests certain drugs and too much iodine, a trace element required by your body to make thyroid hormones, may trigger thyroid disease in susceptible people.
Radiation exposure. Increased cases of thyroid disease have been reported in people exposed to radiation, including the atomic bombs in Japan, the Chernobyl nuclear accident, and radiation treatment for a form of blood cancer called Hodgkin's disease.
Risk Factor
The cause of Hashimoto’s thyroiditis is not known. However, several risk factors have been identified for the disease. It is seven times more likely to occur in women than men, especially women who have been pregnant. Your risk may also be higher if you have a family history of autoimmune diseases, including:
- Graves’ disease
- type 1 diabetes
- lupus
- Sjögren’s syndrome
- rheumatoid arthritis
- vitiligo
- Addison’s disease
Diagnosis
A number of conditions may lead to the signs and symptoms of Hashimoto's disease. If you're experiencing any of these symptoms, your health care provider will conduct a thorough physical exam, review your medical history and ask questions about your symptoms.
Testing thyroid function
To determine if hypothyroidism is the cause of your symptoms, your provider will order blood tests that may include the following:
TSH test. Thyroid stimulating hormone (TSH) is produced by the pituitary gland. When the pituitary detects low thyroid hormones in the blood, it sends TSH to the thyroid to prompt an increase in thyroid hormone production. High TSH levels in the blood indicates hypothyroidism.
T-4 tests. The main thyroid hormone is thyroxine (T-4). A low blood level of T-4 confirms the findings of a TSH test and indicates the problem is within the thyroid itself.
Antibody tests
More than one disease process can lead to hypothyroidism. To determine if Hashimoto's disease is the cause of hypothyroidism, your health care provider will order an antibody test.
The intended purpose of an antibody is to flag disease-causing foreign agents that need to be destroyed by other actors in the immune system. In an autoimmune disorder, the immune system produces rogue antibodies that target healthy cells or proteins in the body.
Usually in Hashimoto's disease, the immune system produces an antibody to thyroid peroxidase (TPO), a protein that plays an important part in thyroid hormone production. Most people with Hashimoto's disease will have TPO antibodies in their blood. Lab tests for other antibodies associated with Hashimoto's disease may need to be done.
Treatment
Most people with Hashimoto's disease take medication to treat hypothyroidism. If you have mild hypothyroidism, you may have no treatment but get regular TSH tests to monitor thyroid hormone levels.
T-4 hormone replacement therapy
Hypothyroidism associated with Hashimoto's disease is treated with a synthetic hormone called levothyroxine (Levoxyl, Synthroid, others). The synthetic hormone works like the T-4 hormone naturally produced by the thyroid.
The treatment goal is to restore and maintain adequate T-4 hormone levels and improve symptoms of hypothyroidism. You will need this treatment for the rest of your life.
Monitoring the dosage
Your heath care provider will determine a dosage of levothyroxine that's appropriate for your age, weight, current thyroid production, other medical conditions and other factors. Your provider will retest your TSH levels about 6 to 10 weeks later and adjust the dosage as necessary.
Once the best dosage is determined, you will continue to take the medication once a day. You'll need follow-up tests once a year to monitor TSH levels or any time after your provider changes your dosage.
A levothyroxine pill is usually taken in the morning before you eat. Talk to your doctor if you have any questions about when or how to take the pill. Also, ask what to do if you accidentally skip a dose. If your health insurance requires you to switch to a generic drug or a different brand, talk to your doctor.
Precautions
Because levothyroxine acts like natural T-4 in the body, there are generally no side effects as long as the treatment is resulting in "natural" levels of T-4 for your body.
Too much thyroid hormone can worsen bone loss that causes weak, brittle bones (osteoporosis) or cause irregular heartbeats (arrhythmias).
Effects of other substances
Certain medications, supplements and foods may affect your ability to absorb levothyroxine. It may be necessary to take levothyroxine at least four hours before these substances. Talk to your doctor about any of the following:
- Soy products
- High-fiber foods
- Iron supplements, including multivitamins that contain iron
- Cholestyramine (Prevalite), a medication used to lower blood cholesterol levels
- Aluminum hydroxide, which is found in some antacids
- Sucralfate, an ulcer medication
- Calcium supplements
- T-3 hormone replacement therapy
Naturally produced T-4 is converted into another thyroid hormone called triiodothyronine (T-3). The T-4 replacement hormone is also converted into T-3, and for most people the T-4 replacement therapy results in an adequate supply of T-3 for the body.
For people who need better symptom control, a doctor also may prescribe a synthetic T-3 hormone (Cytomel) or a synthetic T-4 and T-3 combination. Side effects of T-3 hormone replacement include rapid heartbeat, insomnia and anxiety. These treatments may be tested with a trial period of 3 to 6 months.
lternative medicine
Products with T-3 and T-4 hormones derived from pigs or other animals are available as prescriptions or as dietary supplements, such as Armour Thyroid, in the United States. Concerns about these products include the following:
The balance of T-4 and T-3 in animals isn't the same as in humans.
The exact amount of T-4 and T-3 in each batch of a natural extract product can vary, leading to unpredictable levels of these hormones in your blood.
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