- Hashimoto's Thyroiditis
- Painful Thyroiditis
- Painless Thyroiditis
- Reidel's Thyroiditis
- Acute Suppurative Thyroiditis
In medical terms, the suffix -itis means inflammation; thyroiditis is inflammation of the thyroid gland which may be associated with an underactive thyroid gland or hypothyroidism and in some cases patients have an overactive thyroid gland or hyperthyroidism prior to experiencing hypothyroidism. There are several different kinds of thyroiditis. Although each different type of thyroiditis may cause different symptoms, many times they can be quite similar.
In the case of thyroiditis, hypothyroidism is caused by the destruction of the thyroid gland by an inflammatory process. When thyroid cells are attacked by the inflammation, these cells stop functioning. Without thyroid cells, the thyroid is no longer able to produce enough thyroid hormone to maintain the body's normal metabolism. Hypothyroidism, or an underactive thyroid gland, results.
Although the thyroid gland enlarges with Hashimoto's' thyroiditis and sometimes even has exaggerated contours called bossilations, Hashimoto's thyroiditis does not form discrete nodules or lumps in the thyroid. If you have Hashimoto's thyroiditis and a thyroid lump, it must be examined completely to insure that this nodule does not represent a cancer. This examination is usually done by needle biopsy to prove whether or not the thyroid lump is benign or malignant. Although you are unlikely to develop thyroid cancer and Hashimoto's thyroiditis together, you are at increased risk for a special type of thyroid cancer called a lymphoma which can be treated and cured if discovered early. Therefore, no thyroid nodule should be ignored.
The most common cause of thyroiditis is called Hashimoto's thyroiditis. This form of thyroid disease may also be referred to as chronic lymphocytic thyroiditis. As we have already discussed, this autoimmune form of thyroiditis may run in families. Additionally, families that suffer from non-thyroid autoimmune disease such as Type 1 diabetes or rheumatoid arthritis may also be at risk for the development of Hashimoto's thyroiditis.
Most patients with Hashimoto's thyroiditis don't even realize they have any thyroid disease because the symptoms are initially very mild. Most often the thyroid enlarges slightly so that it appears bulky and larger. This enlargement is due to the inflammatory cells which destroy the thyroid, resulting in long term scarring. When the cells are damaged they cease thyroid hormone production, resulting in hypothyroidism. Again the symptoms are usually mild, e.g. fatigue, difficulty concentrating and weight gain. But they can progress and become quite severe, affecting every organ system in the body as described in the section on hypothyroidism.
Occasionally, if you have Hashimoto's' thyroiditis, you may develop an overactive thyroid (hyperthyroidism), rather than the usual hypothyroidism. Too much thyroid hormone is the result of thyroid hormone release into the blood stream as thyroid cells are destroyed. This hyperthyroid period is generally short, and is followed by a period of time when the thyroid functions properly. Sometimes, however, this period of normal thyroid function is short-lived and as scarring sets in, hypothyroidism results.
The diagnosis of Hashimoto's thyroiditis is simply diagnosed by two blood tests. First the routine thyroid function tests to confirm that a patient has an underactive thyroid gland, and second the thyroid antibody tests (anti-microsomal or anti-thyroglobulin antibodies), which pinpoint Hashimoto's thyroiditis as the cause of the hypothyroidism. Anti-microsomal and anti-thyroglobulin antibodies are immune components which the body produces to attack specific portions of the thyroid cells. The anti-microsomal antibody test is much more sensitive than the anti-thyroglobulin, therefore some doctors use only the former blood test. These thyroid autoantibodies blood tests are high in about 95% of patients with Hashimoto's thyroiditis.
The second type of thyroiditis is called subacute granulomatous thyroiditis, or painful thyroiditis. Unlike most forms of thyroid disease which are more common in women, this type of thyroiditis occurs equally in both men and women. It usually starts out as a harmless viral illness such as the flu or a cold which invades the thyroid gland causing thyroiditis. This type of inflammation is quite painful and you may find that the front of your throat is sore to the touch. Often this pain extends to the jaw or ear and can be confused with a whole host of other diseases including temporomandibular joint problems (commonly referred to as TMJ), ear infections or even Strep throat. Sometimes only one lobe of the thyroid is affected causing pain and swelling on just one side of the neck instead of both.
Gradually the thyroid recovers and stops spilling thyroid hormone into the blood stream. The thyroid gland begins to shrink and becomes less tender. The thyroid cells recover and are usually able to produce normal amounts of thyroid hormone. Occasionally, however, the thyroid has been destroyed and can never produce normal quantities of thyroid hormone. In this case, permanent hypothyroidism results and thyroid hormone replacement medication is necessary.
The diagnosis of painful thyroiditis is made by routine thyroid function blood tests which may initially show an overactive thyroid because of the sudden release of a surplus of thyroid hormone into the blood stream as the thyroid is attacked by the virus. A radioactive iodine scan will show almost no concentration of the radioiodine by the thyroid cells because these cells are temporarily injured during the inflammatory process. In the situation where only one side of the thyroid gland is enlarged, it can mimic the symptoms of thyroid cancer, therefore a thorough history, including recent viral infections, must be considered. In addition, if the thyroid only shrinks on one side after the infection, it also may be misdiagnosed as a thyroid cancer, therefore it is important that you inform your doctor about the painful initial swelling.
Sometimes medications like aspirin or ibuprofen can be taken under the direction of a physician to help decrease the amount of pain. If the thyroid cells recover, no additional medication is needed. However, if the damage is permanent, replacement doses of thyroid hormone medication must be taken for the rest of your life to treat the hypothyroidism. There is no way to tell who will eventually end up with an underactive thyroid gland. Therefore it is very important to have routine visits with your doctor, to make sure that your thyroid gland is still functioning normally. This information is obtained by routine thyroid function blood tests.
The third type of thyroiditis is called subacute lymphocytic thyroiditis, also sometimes referred to as painless thyroiditis. This is the type of thyroiditis that may occur in women after they give birth. Initially the overactive or hyperthyroid phase is more common with the destruction of thyroid tissue caused by inflammation. This results in excess thyroid hormone being released into the blood. As a result you may have a slight enlargement of the thyroid gland and you may notice increased anxiety, restlessness, insomnia, weight loss, and difficulty concentrating.
This overactive phase is diagnosed by blood tests to measure the abnormally increased levels of thyroid hormone in the bloodstream and also sometimes the abnormal antibodies, anti-microsomal and antithyroglobulin antibodies During this hyperthyroid phase, treatment is usually not recommended because this phase usually lasts for a short period of time, about 2 to 4 months. However, if the symptoms are extreme, beta blockers may be used to slow the heart rate and decrease nervousness.
The second phase of postpartum thyroiditis is an underactive or hypothyroid period and usually occurs 3 to 8 months postpartum. This phase can be characterized by a slight enlargement of the thyroid gland and symptoms of weight gain, fatigue, lack of energy and often depression. In fact, some cases of postpartum depression have actually been linked to postpartum thyroid disease and are readily treatable. Permanent hypothyroidism may develop especially if you have high antibody levels or a severe hypothyroid phase. Treatment for this hypothyroid phase is with thyroid hormone medication for about six months. After this time, the medication is stopped to determine whether or not the thyroid has recovered its normal function. If so, the medication may be stopped permanently, otherwise the medication must be resumed because of permanent injury to the thyroid gland.
Another of thyroiditis is called Riedel's invasive fibrous thyroiditis. This is a very rare form of thyroiditis in which the inflammation of the thyroid gland causes it to merge with surrounding structures such as muscle and trachea (windpipe). In fact, many physicians think that this disease is not a form of thyroiditis at all, but rather a rare form of low-grade tumor that happens to involve the fascia (or envelope) of tissue that surrounds the thyroid gland.
The thyroid gland itself becomes quite hard, like a rock and it may be very difficult to tell if this rock-hard thyroid is a result of inflammation or cancer. Blood tests for thyroid function are usually normal except in the extreme cases where the inflammation is so invasive that the thyroid can no longer function properly. In this situation, you may become hypothyroid. A biopsy is necessary in order to distinguish this benign disease from cancer. However, since the thyroid gland in this illness is so hard, a fine needle aspiration biopsy may not be possible. Instead, a biopsy done in the operating room may be necessary.
In the most severe forms of this disease, the thyroid gland becomes so tight and solid that it may squeeze the trachea or breathing tube. In this instance, an operation may be necessary to remove the middle portion of the thyroid and remove this constricting ring. A complete removal of the thyroid gland can not be performed because the thyroid blends with normal muscles and other tissues, making more extensive surgery quite dangerous. Once this little middle portion of the thyroid is removed, the windpipe is no longer constricted and breathing is facilitated.
Acute Suppurative Thyroiditis
Acute suppurative thyroiditis is quite rare. It is caused by a bacterial infection in the thyroid which causes pus to collect and form an abscess within the thyroid gland. The bacterial infection may be carried in the bloodstream from anywhere in the body or it may come from the throat itself. Because antibiotics are now routinely used, this form of thyroiditis has become very rare since bacterial infections are usually treated before they spread to the thyroid gland. In the few instances where it still occurs, antibiotics and surgery to drain the pus can result in complete cure.