RIEDEL'S THYROIDITIS


"In 1896 Riedel described a chronic sclerosing thyroiditis, occurring especially in women, that tends to progress inexorably to complete destruction of the thyroid gland and frequently causes pressure symptoms in the neck 76-78. It is exceedingly rare. In the Mayo Clinic series it occurred approximately on-fiftieth as frequently as Hashimoto's thyroiditis. It is approximately twice as frequent in men as in women and is found most often in the 30- to 60- year age group. The thyroid gland is normal in size or enlarged, usually symmetrically involved, and extremely hard. Occasionally involvement may be unilateral. Diagnostic confustion with sarcoma of the thyroid region has been reported79. On pathologic examination the gland is replaced by dense fibrosis in which are scattered solitary follicular cells and occasional acini with small amounts of colloid. The fibrosis binds the thyroid firmly to the trachea and the strap muscles, from which it can be separated only with the greatest difficulty (ligneous thyroiditis) 80. The fibrosis may compress the trachea or esophagus. The disease may remain stable over many years, or it may progress slowly and produce hypothyroidism. Dyspnea, dysphagia, hoarseness, and aphonia are caused by the local pressure, and if there is enough pressure on both recurrent laryngeal nerves, there may be stridor. Sometimes the disease is asymptomatic and discovered only incidentally. The pathologic process may advance to complete replacement of the gland, and then symptoms and signs of hypothyroidism appear. Involvement of the parathyroid glands by the fibrotic process may result in hypoparathyroidism 81-84. Rarely, Riedel's thyroiditis may be associated with similar fibrosclerotic processes in other areas, including the lacrimal glands, orbits, parotid glands, mediastinum, lung, myocardium, retroperitoneal tissues, and bile ducts in varying combinations in the syndrome of multifocal fibrosclerositis85. Fluorine-18 fluorodeoxyglucose positron emission tomographic images have shown metabolic activity in an abdominal mass and increased glucose metabolism I the thyroid, probably resulting from active inflammation involving lymphocytes, plasma cells and fibroblant proliferation86. This mixture of inflammatory cell infiltrate and fibrosis can also be visualised using dynamic magnetic resonance imaging with gadpentate dimeglumine87 and appropriate T1- and T2- weighted images88. Subcutaneous fibrosclerosis has also been noted but it is very rare 89. The occurrence of cerebral sinus thrombosis suggests that Riedel's thyroiditis may cause venous stasis, vascular damage, and possibly hypercoaguability 90. The results of laboratory tests of thyroid function are usually normal, but about one-third are hypothyroid. The erythrocyte sedimentation rate is not elevated, as in subacute thyroiditis, and there is no leukocytosis. Antithyroid antibodies are present in 67% of reported cases 78 and a mixed population of B- and T-cells is present in the thyroid, suggesting an autoimmune etiology or association. The occurrence of marked tissue eosinophilia and the extracellular deposition of eosinophil granule major basic protein suggests a role for eosinophils and their products in the development of fibrosis in Riedel's thyroiditis 91. Fibrosis may also be related to the action of TGF beta 1, as seen in murine thyroiditis 92. The manifestations of Riedelís thyroiditis can be confusing. A patient was recently reported who, over 18 months after biopsy proven Riedelís thyroiditis, developed hyperthyroidism, spontaneous primary hypoparathyroidism, acute compressive neck symptoms requiring emergency isthmusectomy, vocal cord paralysis, syncopal-like episodes, and Hornerís syndrome due to compression of the right carotid sheath. This patient is under therapy with glucocorticoids and tamoxifen (Yasmeen, T; Khan, S; Patel, SG; Reeves, WA; Gonsch, FA; de Bustros, A; Kaplan, EL. Riedelís thyroiditis: Report of a case complicated by spontaneous hypoparathyroidism, recurrent laryngeal nerve injury, and Hornerís syndrome. J Clin Endocrinol Metab 87 3543-3547 2002).

Management of Riedel's Thyroiditis
Although there is no specific therapy for Riedel's thyroiditis, several management strategies are available dependent on the clinical features of the disease in the individual patient. Corticosteroid therapy has been found to be effective in some cases 85,93-95., probably those with active inflammation. Initial doses of up to 100mg per day of prednisolone have been used but sustained improvement has been reported with lower doses of 15-60 mg per day 85. There are no controlled trials of steroid therapy in Riedel's and although some patients obtain long term benefit after steroid withdrawal96 others may relapse97. The reasons for this variation are unclear but inflammatory activity and duration of disease may be relevant factors. In those who fail to respond to steroid therapy or relapse after withdrawal tamoxifen therapy should be tried. Two reports have described an encouraging response with this agent, admittedly in only a small number of patients 98,99. It is possible that Tamoxifen acts in Riedel's by inhibition of fibroblast proliferation through the stimulation of TGF beta.

As hypothyroidism is rare in Riedel's, thyroxine therapy is usually not required and is not thought to influence the course of the disease. Surgical intervention may be necessary to release the trachea or perform tracheotomy in the case of severe stridor. Unilateral lobectomy has been performed for unilateral disease 100 and larger resections should be considered in some instances. It is recommended that surgical exploration and biopsy are usually required to exclude malignancy which may be suspected at presentation.

RARE INFLAMMATORY OR INFILTRATIVE DISEASES
In addition to the varieties of thyroiditis already mentioned, which are diseases specifically of the thyroid gland, generalized or systemic diseases may also involve the thyroid gland 20. The lesions of sarcoid may appear in the thyroid gland of patients with systemic sarcoidosis, and huge deposits of amyloid occasionally causes goiter in amyloidosis. Painless thyroiditis has been noted in a woman with rheumatoid arthritis and secondary amyloidosis infiltrating the thyroid gland101. Radiotherapy for tonsillar carcinoma has been reported to result in thyroiditis102 and radiation during 131 I therapy produces thyroiditis, which is occasionally symptomatic. This situation is discussed in Chapters 11 and 18. Irradiation to the thyroid during therapy for breast cancer or lymphoma can also induce hypothyroidism. Therapy should be directed toward the primary disease rather than the thyroid, but administration of thyroid hormone may be necessary if destruction of thyroid tissue is sufficient to produce hypothyroidism. Finally, surgery to the neck has been reported to cause throiditis but this is rare103.

SUMMARY
The thyroid, like any other structure, may be the seat of an acute or chronic suppurative or nonsuppurative inflammation. Various systemic infiltrative disorders may leave their mark on the thyroid gland as well as elsewhere. Infectious thyroiditis is a rare condition, usually the result of bacterial invasion of the gland. Its signs are the classic ones of inflammation: heat, pain, redness, and swelling, and special ones conditioned by local relationships, such as dysphagia and a desire to keep the head flexed on the chest in order to relax the peritracheal muscles. The treatment is that for any febrile disease, including specific antibiotic drugs if the invading organism has been identified and its sensitivity to the drug established. Otherwise, a broad-spectrum antibiotic may be used. Surgical drainage may be necessary and a search for a pyriform sinus fistula should be made, particularly in children with thyroiditis involving the left lobe. Subacute (granulomatous) thyroiditis is a more common and protracted disease that usually involves the thyroid symmetrically. The gland is swollen and tender, and the systemic reaction may be severe, with fever and an elevated erythrocyte sedimentation rate. During the acute phase of the disorder, tests of thyroid function disclose a diminished thyroidal RAIU and increased serum concentrations of T4, T3, and Tg. The cause of this disease has been established in only a few instances in which a viral infection has been the initiating factor. There may be repeated recurrences of diminishing severity. Usually, but not always, the function of the thyroid is normal after the disease has subsided. Subacute thyroiditis may be treated with rest, non-steroidal anti-inflammatory drugs or aspirin, and thyroid hormone. If the disease is severe and protracted, it is usually necessary to resort to administration of glucocorticoids, but recurrence may follow their withdrawal. Riedel's thyroiditis is a chronic sclerosing replacement of the gland that is exceedingly rare. The process involves the immediately adjacent structures, making any surgical attack very difficult. The cause is unknown, and no treatment is available beyond resecting the isthmus of the thyroid gland to relieve the symptoms of tracheal or esophageal compression. Sarcoid may involve the thyroid, and amyloid may be deposited in the gland in quantities sufficient to cause goiter. In all of these diseases it may be necessary to give the patient levothyroxine replacement therapy if the function of the gland has been impaired."


The five different kinds of thyroiditis
"Hashimoto's Thyroiditis
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 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 slightly enlarges so that it appears bulky and larger. This enlargement is due to the inflammatory cells which destroy thyroid cells, 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 be 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 cells 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.

Thyroid Inflammation vs. Thyroid Lumps
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.


Painful 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 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 Strept 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 so destroyed that it can never produce normal quantities of thyroid hormone. In this case, permanent hypothyroidism results and 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 mimics 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, therefor eit is important that you inform your doctor about the painful initial swelling.

Sometimes medications like aspirin or ibuprofen can be taken 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.

Painless Thyroiditis
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. Within the first one to four months after delivery, the hyperthyroid or overactive phase is most common. 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 A fine needle aspiration biopsy of the thyroid gland during this phase would reveal inflammatory cells attacking the thyroid gland. 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.

This 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, many cases of so called 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.

Reidel's Thyroiditis
The fourth type of thyroiditis is called Reidel'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 phsyicians 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 in modern times. 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."




Links

RIEDEL'S THYROIDITIS

Diagnosis: Reidel's Thyroiditis X-ray showing enlarged thyroid. "Findings: 1) Large neck soft tissue mass involving the left greater than the right with encasement of local structures. Findings suggest a large goiter or Reidel's struma. However, cannot exclude lymphoma or primary tumor of the thyroid. 2) Tracheal stenosis measuring 6 mm diameter. 3) Left internal jugular compression without complete occlusion."

eMedicine Riedel Thyroiditis "RT is defined by the replacement of normal thyroid parenchyma with dense fibrotic tissue and by the extension of this fibrosis to adjacent structures of the neck.
Patients typically present with a hard fixed painless goiter. The character of the thyroid gland is often described as stony or woody. The onset of the goiter may be sudden or gradual.
Involvement may be unilateral or bilobar.
Thyroid function depends on the extent to which the normal thyroid gland has been replaced with fibrosis. Most patients are euthyroid. Hypothyroidism is noted in approximately 30% of cases. Rarely, hyperthyroidism can occur.
Local compressive symptoms, such as dyspnea, dysphagia, hoarseness, and cough, are frequent. Such symptoms are the result of the increasing thyroid mass or of the extension of the fibrotic process to adjacent neck structures (eg, strap muscles, trachea, esophagus, recurrent laryngeal nerve).
Hypoparathyroidism is rare and presumably reflects fibrotic involvement of the parathyroid glands. Recurrent laryngeal nerve paralysis is also uncommon, but it can be observed in extensive disease."

What is Reidel's Thyroiditis? "This is an exceptionally rare condition. In 25 years the author has only seen 6 cases. Although the patient has a woody hard thyroid, the disease does not arise from the thyroid gland. The soft tissue in the neck is invaded by fibrous tissue, which strangulates the neck structures causing swallowing and breathing difficulties. Treatment is difficult; steroids may control the progress of the disease but the effect is usually temporary. The breast anti-cancer drug tamoxifen may also be effective. Surgery is limited to freeing the windpipe and is horrendously difficult!"





Results 1-15 of about 40 containing "reidel thyroiditis" Underconstruction. More to come soon.