Destructive thyroiditis followed by hypothyroidism associated with infliximab therapy.

Objective: To present the rare case of a patient who developed destructive thyroiditis accompanied by transient thyrotoxicosis resulting from infliximab therapy for the treatment of psoriasis.

Methods: The clinical presentation and management of a case with infliximab-associated thyroiditis is described with a brief review of the literature.

Results: A 57-year-old male who suffered from psoriasis was treated with infliximab therapy for 4 years. Thyroid function tests were normal before infliximab therapy. When the patient presented in our clinic, he had thyrotoxicosis and was using propylthiouracil. A 99m Technetiumpertechnetate thyroid scintigraphy scan showed no visualization of either thyroid lobe or decreased thyroid iodine uptake. Thyroid-stimulating hormone (TSH) receptor antibody, thyroid peroxidase antibody (anti-TPO Ab) and thyroglobulin antibody (anti-Tg Ab) were negative. Thyroid ultrasonography revealed a heterogeneous thyroid gland without nodules. After stopping propylthiouracil therapy, we advised monitoring of his thyroid function tests in the following weeks, and infliximab therapy for psoriasis was continued. Four weeks later, his thyroid function tests showed an elevated TSH level with normal levels of free triiodothyronine and thyroxine (FT3 and FT4, respectively), and levothyroxine treatment was administered to the patient. Thyroid function tests normalized after levothyroxine treatment. One year later, infliximab therapy was stopped because of clinical remission. Simultaneously, levothyroxine treatment was also stopped. His thyroid function tests were normal 6 weeks after the cessation of levothyroxine treatment.

Conclusion: To our knowledge, the present report is the third infliximab-associated thyroid disorder case. Periodic follow-up of thyroid function tests is necessary during infliximab therapy.