What is the management of Riedel's thyroiditis, initially and in cases of no response to corticosteroids (CS)?

Management of Riedel's Thyroiditis

For patients with Riedel's thyroiditis who fail to respond to corticosteroid therapy, decompressive isthmectomy followed by tamoxifen should be performed as second-line treatment. 1, 2, 3

Initial Management

• Corticosteroids are the first-line medical treatment for the inflammatory component of Riedel's thyroiditis 4

  • High-dose prednisone (typically starting at 40-60 mg daily) is recommended initially 2, 4
  • Corticosteroid therapy should be continued for at least 2-3 months to evaluate response 3, 4

• Thyroid hormone replacement therapy should be initiated concurrently for associated hypothyroidism 4

  • Levothyroxine dosing should be adjusted based on TSH levels 4

Management of Corticosteroid-Resistant Disease

Surgical Intervention

• Decompressive isthmectomy should be performed when there is no response to corticosteroids, especially with persistent compressive symptoms 1, 2
  • Surgical decompression helps relieve mechanical compression on adjacent structures including trachea, esophagus, and parathyroid glands 1
  • Complete thyroidectomy is often not feasible due to dense fibrosis obliterating surgical planes 2

Medical Management After Surgery

• Tamoxifen should be initiated after surgical decompression 3, 5

  • Recommended dosage: 20 mg twice daily 3
  • Tamoxifen acts as an anti-fibrotic agent by inhibiting fibroblast proliferation and reducing collagen deposition 3, 5
  • Duration of therapy typically ranges from 3-12 months, with clinical response often seen within 2-3 months 3

• For cases resistant to both corticosteroids and tamoxifen, rituximab should be considered 2

  • Dosing: 375 mg/m² intravenously every 3 weeks for 4 doses 2
  • Rituximab is particularly effective in cases with elevated IgG4 levels, as Riedel's thyroiditis may be part of the IgG4-related disease spectrum 2

• Mycophenolate may be considered as an alternative immunosuppressive agent in refractory cases 2

Monitoring and Follow-up

• Regular clinical assessment for improvement in compressive symptoms 1, 2
• Serial imaging (ultrasound or CT) to objectively monitor changes in thyroid size and fibrosis 2, 3
• Monitoring of calcium and parathyroid hormone levels, as hypoparathyroidism may resolve with treatment 1, 4
• Thyroid function tests to adjust levothyroxine dosage as needed 4

Special Considerations

• Hypoparathyroidism associated with Riedel's thyroiditis may be reversible with appropriate treatment of the underlying condition 1, 4

  • Calcium and vitamin D supplementation should be provided until parathyroid function recovers 1

• The combination of surgical decompression and immunomodulatory therapy provides better outcomes than either approach alone 1, 2

• Treatment response should be assessed both subjectively (improvement in compressive symptoms) and objectively (reduction in thyroid size on imaging) 2, 3