Conditions: Riedel’s Thyroiditis

What is Riedel’s Thyroiditis?

Riedel's thyroiditis is a rare, chronic disorder that affects the thyroid gland. This condition is characterized by inflammation the replacement of the normal thyroid tissue with dense fibrous tissue, causing the gland to stop producing adequate thyroid hormone (hypothyroidism), become enlarged and very hard, but is usually not painful.

Essentially, the inflammation associated with Riedel’s thyroiditis is different from that of other thyroid inflammatory diseases, such as Hashimoto’s, in that Riedel’s thyroiditis leads to progressive fibrosis (scar tissue) within the thyroid and potentially beyond the thyroid to to the surrounding tissues.

who gets Riedel’s thyroiditis?

Riedel's thyroiditis is rare. The rate of incidence of Riedel’s thyroiditis is estimated at less than one new case per 100,000 population per year. It primarily affects women between the ages of 30 and 60, with a female-to-male ratio of 4:1.

What problems does Riedel’s thyroiditis cause?

Symptoms of Riedel’s thyroiditis result from the development of scar tissue (fibrosis). Within the thyroid, as scar tissue replaces the normal gland, hypothyroidism can develop over time. If the fibrosis extends outside of the thyroid, symptoms depend on structures involved. Involvement of neck muscles or esophagus may cause difficulty swallowing. Nearby parathyroids may succumb to the process, potentially leading to hypoparathyroidism. Fibrosis compressing or extending into the trachea (windpipe) may cause shortness of breath. If the larynx (voice box) or the nerves to the the larynx are affected, hoarseness can ensue. Horner’s syndrome may occur with extension to the cervical sympathetic plexus of nerves.

How is Riedel’s thyroiditis diagnosed?

Diagnosis can be suspected clinically with a physical exam. Ultrasound (or other imaging studies) may demonstrate nodules and the presence of fibrosis. A biopsy showing dense fibrous tissue demonstrating Riedel’s characteristic microscopic pattern can confirm the diagnosis, and distinguish this condition from other more common thyroid problems.

How is Riedel’s thyroiditis treated?

Monitoring and treating hypothyroidism is a necessary component of treatment for Riedel’s thyroiditis. Addressing the inflammation and fibrosis is mainly undertaken with the use of steroids which can cause a dramatic improvement in symptoms. Use of alternative medications such as tamoxifen and mycophenolate has been described. Radiation therapy may also be used when medications have failed. Surgery is considered a last resort therapy when all other treatments have failed.