- What is Hashimoto’s disease
- Symptoms
- Associated diseases
- Examinations and testing
- Treatment
- Daily life
- Pregnancy and Hashimoto’s disease
What is Hashimoto’s disease?
Hashimoto’s disease is characterized by chronic inflammation of the thyroid gland. It is also called chronic thyroiditis. Among thyroid diseases, Hashimoto’s disease is much more common in women than men, with a male-to-female ratio of between 1:20 and 1:30. When comparing age groups, Hashimoto’s disease is common in people in their late 20s or older, particularly those in their 30s and 40s, but it is rare in toddlers and school children. Hashimoto’s disease is an autoimmune disorder. However, it is still not clear what triggers the autoimmune dysfunction. Inflammation due to an autoimmune disorder can cause thyroid swelling and lead to thyroid dysfunction.
Age distribution of Hashimoto’s disease patients at the time of their first visit to Ito Hospital (new, untreated patients in 2020)
Women in their 30s and 40s are common. This in part due to advances in research regarding the relationship between thyroid hormones and rates of fertility and miscarriage. Women increasingly seek care at hospitals for examinations regarding pregnancy.
Hashimoto’s disease and hypothyroidism
- Origin of the disease name
- Hashimoto’s disease was named after Dr. Hakaru Hashimoto, a surgeon at Kyushu University. He was the first to describe the disease, publishing an article in a German medical journal in 1912.
Not all patients with Hashimoto’s disease develop hypothyroidism. While chronic inflammation of the thyroid gland is Hashimoto’s disease, thyroid function may remain normal when inflammation is mild. However, if inflammation progresses, thyroid function worsens, leading to hypothyroidism. For patients with Hashimoto’s disease, approximately 10% have clear symptoms of hypothyroidism, 20% have asymptomatic mild hypothyroidism, and the remaining 70% have normal thyroid function.
Symptoms
Thyroid swelling (goiter)
In Hashimoto’s disease, the entire thyroid swells and enlarges. This swelling (goiter) may be detected during health check-ups, leading to diagnosis. The size of goiter varies, ranging from a nearly normal-sized thyroid to one that is obviously enlarged. Basedow’s disease also causes thyroid swelling, but Hashimoto’s disease goiters tend to be comparatively harder and have bumpy surfaces.
■ Normal thyroid gland
■ Normal thyroid gland
Symptoms of hypothyroidism
Hypothyroidism is a condition characterized by insufficient levels of thyroid hormones in the blood. Since thyroid hormones regulate metabolism, their lack can causes a variety of symptoms (detailed below). Symptoms improve with appropriate treatment. Patients with Hashimoto’s disease who have normal thyroid function do not develop the following symptoms due to their thyroid gland.
(1)Edema A characteristic of edema in Hashimoto’s disease patients is that skin returns to a swollen state even after it is pushed and depressed by a finger. Edema may be present in any part of the body, but it tends to appear in the hands and face when waking up in the morning and slightly improves around noon. If there is edema of the lips, tongue, or mucosa deep in the throat, a patient’s voice may become low, making it difficult to speak.
■Healthy state
(normal thyroid function)
■ State of edema
(reduced thyroid function)
(2)Skin symptoms Since metabolism decreases, the skin dries and becomes rough. Sweating is reduced, and patients may suffer hair loss.
(3)Sensitivity to cold As metabolism lowers, heat production in the whole body is reduced, leading to increased sensitivity to cold.
(4)Lack of appetite accompanied by weight gain The worsening of gastrointestinal function reduces appetite, leading people to eat less. At the same time, metabolism decreases and edema occurs, causing in weight gain. In addition, patients tend to feel bloated and suffer from constipation.
(5)Slowed heart rate Heart activity slows, resulting in a lower heart rate and weak pulse. If hypothyroidism is severe, fluid may accumulate in the sac covering the heart (pericardium), causing heart enlargement.
(6)Sluggishness People may become forgetful or inactive, lacking motivation and spirit to do things. Some people may experience drowsiness, difficulties speaking, and slowed speech.
(7)Muscle symptoms Muscles weakness and shoulder stiffness can grow severe.
(8)Irregular menstruation Heavy or prolonged menstrual bleeding can occur (menorrhagia).
Associated diseases
Painless thyroiditis
As the name suggests, this disease occurs without pain. Painless thyroiditis occurs when the thyroid becomes inflamed and thyroid hormones stored in the gland leak into the blood. This leads to a temporary excess of thyroid hormones, but the condition thereafter resolves naturally. When hormone levels are high, symptoms may cause it to be confused with Basedow’s disease. Normally, painless thyroiditis disappears naturally without treatment in 1-4 months.
Acute exacerbation of Hashimoto’s disease
Acute exacerbation of Hashimoto’s disease is rare. Pain in the thyroid and fever occur repeatedly. While these symptoms appear and disappear, thyroid function may decline relatively rapidly. The disease is treated with analgesics or steroid hormones. If symptoms recur and it is difficult to discontinue drug therapy, then surgery may be performed to treat the condition.
Malignant lymphoma
Chronic inflammation of the thyroid occurs in Hashimoto’s disease, and lymphocytes invade the gland. Normally, there is no lymphoid tissue in the thyroid. These invasive lymphocytes can transform into cancerous cells and cause malignant lymphoma. In patients with malignant lymphoma in the thyroid, approximately 90% have Hashimoto’s disease, showing an association. However, only a very small proportion of patients with Hashimoto’s disease actually develop malignant lymphoma. Overall, lymphoma developing from the thyroid is very rare. It accounts for only 1-2% of all malignant lymphomas and 2-5% of malignant tumors of the thyroid gland.
(1)Symptoms and tests If the thyroid enlarges swiftly or swells like a tumor, ultrasonography and a cytological testing will be performed. Surgery, such as exploratory thyroid incision, will also be performed for further examination. Surgery allows us to confirm malignant lymphoma and determine its specific type. In addition, computed tomography (CT scan) examination, gallium scintigraphy, positron emission tomography (PET)-CT, and bone marrow aspiration will be performed to determine the extent of the disease’s spread.
(2)Treatment and prognosis Depending on the type and the spread of the disease, we will perform treatments such as radiation therapy, antibody therapy (treatment targeting a specific molecule on the surface of lymphoma cells), or chemotherapy. The word “malignant” makes some patients feel that treatment will not be effective, but anticancer medication and radiation therapy tend to be effective.
Examinations and testing
Hashimoto’s disease is diagnosed by the detection of diffuse goiter (swelling of the entire thyroid) and autoantibodies targeting the thyroid gland. In addition, thyroid hormone levels are measured to assess whether treatment is required.
Blood tests
(1)Thyroid function test Levels of thyroid hormones (FT3 and FT4) and thyroid-stimulating hormone (TSH) in the bloodstream are measured. Normal or reduced thyroid function is assessed based on the balance of the hormone levels.
(2)Antithyroid antibodies test This is a test for the presence of autoantibodies that attack the thyroid. The antibodies are thyroglobulin antibodies (TgAb) and thyroid peroxidase antibodies (TPOAb).
(3)General blood screening for abnormalities Persistently low thyroid hormone levels may lead to higher blood cholesterol levels.
Ultrasonography
Ultrasonography is performed to detect thyroid swelling and the presence of tumors.
Fine-needle aspiration biopsy
This test is rarely used to diagnose Hashimoto’s disease. However, it may be performed if the disease is associated with malignant lymphoma or other tumors.
Treatment
Treatment for hypothyroidism
(1)Oral medication Hypothyroidism is a condition that occurs when the thyroid does not produce sufficient levels of hormones, requiring treatment. Patients with hypothyroidism take an appropriate oral dosage of thyroid hormone medication (trade name: Thyradin-S ®, Levothyroxine Na Tablets 25mcg "SANDOZ” ®) to restore thyroid hormone levels to a normal range. Thyroid hormone medications like Thyradin-S ® have a half-life of approximately 1 week. If patients continue to take the medications, there is little effect on blood concentration even if there is a mistiming of taking a dose. For this reason, whenever you take the medication, there hardly any effects based related to the concentration in the blood. However, according to recent studies, the body absorbs these medications a little more easily if taken before sleep or on an empty stomach instead of following meals. In general, thyroid hormone medication is taken once a day, regardless of dosage. However, patients who are elderly, suffer heart palpitations due to the medication, or have complications stemming from heart disease, may need to divide their daily amount into multiple doses. Medication used to treat anemia inhibits the absorption of thyroid hormone medications in the intestines. Patients should take anemia medication at least two hours apart from thyroid hormone medication. In addition, coffee also hinders absorption of thyroid hormone medication, so it should be consumed at a separate time. Since thyroid hormone medication is chemically synthesized human thyroid hormones, there should be no side effects. However, in extremely rare cases, there can be allergic reactions to components that are used in making a pill such as coloring agents and other inactive ingredients.
(2)Necessity of treatment Thyroid hormone replacement therapy is the standard treatment for hypothyroidism. In general, if patients have normal thyroid function, no treatment is required. However, it should be noted that under special conditions, such as pregnancy, oral medication may be deemed appropriate even if thyroid function is normal.
(3)Precautions for treatment
- Since a high initial dose may place a burden on the heart, patients who have heart disease, severe hypothyroidism, or are elderly will start treatment with a low dosage and then gradually increase the amount of medication.
- Whereas patients with temporary hypothyroidism may be able to gradually reduce their dosage, those with permanent hypothyroidism must continue to take an appropriate dosage indefinitely.
- If hypothyroidism is left untreated, decreased metabolism can lead to high blood cholesterol levels which may accelerate arteriosclerosis. Also, since an excessive oral dose may place a burden on the heart and bones, it is important to have regular examinations and take an appropriate dosage of thyroid hormone medication.
Treatment for thyroid enlargement
Generally, no treatment is needed for thyroid enlargement due to Hashimoto’s disease. However, if the thyroid swells to an exceptionally large size and hardens, it may interfere with daily life. For example, an excessively large thyroid can cause severe difficulties in swallowing or an inability to bend forward due to a feeling of pressure in the neck. In these situations, surgery to remove the goiter may be considered.
Daily life
Precautions for daily life
(1) Patients with normal thyroid function and those whose treatment has normalized their thyroid hormone levels can go about their daily life without restrictions. There are no problems regarding activities such as sports and travel.
(2) When hypothyroidism is severe, vigorous exercise and sports may cause persistent muscle pain. Rest may be required until hormone levels improve.
(3) Patients with hypothyroidism receiving oral treatment need to take medication every day. Long-term interruption of medication will cause a relapse of hypothyroidism.
Meals
Thyroid function may be affected by dietary habits, including continued and high intake of kelp, rich in iodine, and daily use of gargling medications that contain iodine to prevent colds. Sometimes it is said that high intake of soy products or cruciferous vegetables, such as broccoli and cabbage, causes goiter enlargement or affects thyroid function. However, in reality these foods cause no harm unless considerably quantities are consumed daily over lengthy periods of time. Please try to eat a balanced diet.
Regular hospital visits and examinations
Thyroid function may be affected by dietary habits, including continued and high intake of kelp, rich in iodine, and daily use of gargling medications that contain iodine to prevent colds. Sometimes it is said that high intake of soy products or cruciferous vegetables, such as broccoli and cabbage, causes goiter enlargement or affects thyroid function. However, in reality these foods cause no harm unless considerably quantities are consumed daily over lengthy periods of time. Please try to eat a balanced diet.
Pregnancy and Hashimoto’s disease
The incidence of Hashimoto’s disease is comparatively high in women. It is more common for women with Hashimoto’s disease to have normal thyroid function than to suffer from hypothyroidism. As a result, female patients are often diagnosed with Hashimoto’s disease for the first time when they are pregnant or undergoing infertility treatment.
The most important thing for a safe pregnancy
If thyroid function remains low during pregnancy, the risks of miscarriage and premature delivery increase. For safe pregnancy and childbirth, it is important to supplement thyroid hormones in advance so that thyroid hormone levels are normalized.
Treatment during pregnancy
Since thyroid hormones play an important role in fetal development and are provided from the mother through the placenta, demand for thyroid hormones during pregnancy than before. If patients wish to become pregnant, thyroid hormone replacement therapy may be started even if hormone levels are within the normal range. Levels of thyroid-stimulating hormone (TSH) are used as an indicator. In the case that thyroid hormone replacement therapy begins before pregnancy, the dosage will need to be adjusted after childbirth. In thyroid hormone replacement therapy, oral administration of thyroid hormone medication (Thyradin-S ®) does not affect babies. If patients realize they are pregnant, they should see a doctor as soon as possible without discontinuing oral medication.
Choosing a hospital for giving birth
Patients who are undergoing thyroid hormone replacement therapy and have normal thyroid function can give birth normally. There are no restrictions regarding hospitals.
After childbirth
Following childbirth, the dosage of thyroid hormone replacement medication will return to the level used prior to pregnancy. Patients continuing replacement therapy are welcome to breastfeed. Thyroid function often changes after childbirth for patients with Hashimoto’s disease. Patients should regularly visit the hospital for monitoring after childbirth.