OVERVIEW

What is sclerosing thyroiditis?

In 1883, German physician Bernhard Riedel discovered a type of thyroid inflammation that caused fibrotic changes in the thyroid, making it enlarged, rock-hard, and painless. He reported and described this thyroid inflammation in 1896.

Later studies confirmed that this thyroid fibrosis could also affect adjacent tissues, such as the parathyroid glands, recurrent laryngeal nerve, and trachea. It is often associated with fibrotic lesions in other areas (retroperitoneum, mediastinum, eyes, etc.) or Hashimoto's thyroiditis, and the condition gradually worsens over time.

Therefore, this disease is referred to as sclerosing thyroiditis, also known as Riedel's thyroiditis.

Sclerosing thyroiditis has many alternative names, including: Riedel's thyroiditis, fibrous thyroiditis, invasive thyroiditis, woody thyroiditis, and RT.

When combined with hypothyroidism, levothyroxine treatment is administered. Glucocorticoids and other medications may also be used to alleviate symptoms. Surgical intervention is required if significant compressive symptoms occur in the neck.

Is sclerosing thyroiditis common?

This disease is extremely rare. Among outpatient cases, only 1 in 100,000 people is diagnosed with it.

Who is more likely to develop sclerosing thyroiditis?

Women are more susceptible than men, and the onset typically occurs between the ages of 30 and 50.

SYMPTOMS

What are the common manifestations of sclerosing thyroiditis?

Patients with this condition experience gradual enlargement of one or both thyroid glands, which progressively involves adjacent thyroid tissues. The hard, swollen tissue compresses surrounding organs, leading to symptoms such as dysphagia, dyspnea, hoarseness or even loss of voice, neck pressure, and swollen cervical lymph nodes, often accompanied by general fatigue.

Initially, few cases of Riedel's thyroiditis combined with hypothyroidism were reported. However, subsequent reports indicate that up to 80% or more patients develop hypothyroidism, possibly due to concurrent Hashimoto's thyroiditis.

Patients with hypothyroidism may experience symptoms such as cold intolerance, constipation, hair loss, and edema.

Additionally, a very small proportion of patients may develop Graves' disease, leading to hyperthyroidism symptoms, including heat intolerance, excessive sweating, palpitations, hand tremors, increased appetite, and rapid weight loss.

Some patients may also develop hypoparathyroidism, presenting with symptoms like numbness in the hands and feet, muscle spasms, nausea, vomiting, and mental abnormalities.

Can sclerosing thyroiditis cause serious consequences?

In severe cases, this disease can lead to bronchial compression, dyspnea, recurrent pneumonia, and even death.

CAUSES

What causes sclerosing thyroiditis?

The exact cause of this disease is currently not very clear. Most viewpoints attribute its etiology to chronic thyroid inflammation caused by abnormal autoimmune reactions.

Infiltration of thyroid tissue by lymphocytes, plasma cells, eosinophils, etc., venous vasculitis, fibroblast proliferation, and other factors lead to thyroid fibrosis and may involve adjacent tissues.

DIAGNOSIS

What tests are needed for sclerosing thyroiditis?

• Thyroid function: Used to assess whether there is hypothyroidism for targeted treatment.
• Thyroid peroxidase antibodies and thyroglobulin antibodies: Used to determine if coexisting Hashimoto's thyroiditis is present, as these antibody levels are higher in Hashimoto's thyroiditis patients than in Riedel's thyroiditis patients.
• Serum parathyroid hormone, calcium, phosphorus: Used to evaluate parathyroid function and determine if hypoparathyroidism exists.
• Thyroid ultrasound: Used to assess thyroid position, size, shape, and detect nodules or abnormal echoes.
• Neck CT or MRI: Used to evaluate the extent of thyroid fibrosis and its impact on surrounding tissues.
• Thyroid fine-needle aspiration biopsy: Can confirm whether it is Riedel's thyroiditis.

What diseases is sclerosing thyroiditis easily confused with?

This condition is easily confused with Hashimoto's thyroiditis, thyroid cancer, and painless thyroiditis. Differentiation can be made based on medical history, the above manifestations, and test results.

TREATMENT

Which department should I visit for sclerosing thyroiditis?

Endocrinology.

How is sclerosing thyroiditis treated?

• When combined with hypothyroidism, levothyroxine treatment is administered.
• Medications such as glucocorticoids, tamoxifen, and mycophenolate mofetil can also be used to alleviate symptoms.
• If there are significant compressive symptoms in the neck, such as difficulty breathing or swallowing, surgical removal of the thyroid may be necessary.

What precautions should be taken when using levothyroxine tablets to treat sclerosing thyroiditis?

Levothyroxine tablets should be taken 0.5–1 hour before breakfast.

Certain foods or medications, such as coffee, soy products, dietary fiber additives, as well as aluminum hydroxide, calcium supplements (e.g., calcium carbonate, calcium citrate, calcium acetate), cholestyramine, sucralfate, and ferrous sulfate, can reduce the absorption of levothyroxine in the small intestine.

The interval between taking levothyroxine and these foods or medications should be at least 4 hours.

Is follow-up required after treatment for sclerosing thyroiditis? How should it be done?

Follow-up is necessary.

• For patients undergoing levothyroxine treatment, thyroid function should be checked every 4–6 weeks during the initial treatment or dose adjustment phase. Once thyroid function stabilizes, the follow-up interval can be gradually extended to every 6–12 months.
• For patients using other medications such as glucocorticoids or tamoxifen, follow-up should be conducted as directed by the doctor.

Can sclerosing thyroiditis be cured?

This condition can only be cured by surgical removal of the thyroid.

DIET & LIFESTYLE

What should patients with sclerosing thyroiditis pay attention to in their diet?

When this disease is complicated by Hashimoto's thyroiditis, excessive intake of iodine-rich foods should be avoided; patients with hyperlipidemia should maintain a light diet.

Can patients with sclerosing thyroiditis have normal fertility?

When this disease is complicated by hypothyroidism, untreated or inadequately managed hypothyroidism during pregnancy may adversely affect both the mother and fetus. However, active treatment can minimize these negative effects.

For patients with pre-existing hypothyroidism, thyroid-stimulating hormone (TSH) levels should be controlled below 2.5 mIU/L before conception.

PREVENTION

Can sclerosing thyroiditis be prevented?

There is no specific prevention method for this disease, only early detection and early treatment.