Endocrine Abstracts

Introduction: Infliximab is a tumour necrosis factor (TNF) α inhibitor and used for the treatment of psoriasis. Herein, we report a case of destructive thyroiditis accompanied by transient thyrotoxicosis resulting from the infliximab therapy for the treatment of psoriasis.

Case report: A 57-year-old man suffered from psoriasis and 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. The ^99mtechnetium-pertechnetate thyroid scintigraphy showed no visualization of both thyroid lobes and decreased thyroid iodine uptake. TSH receptor antibody, thyroperoxidase antibody and thyroglobulin antibody were negative. Thyroid ultrasonography revealed a heterogeneous thyroid gland (5.5×1.7×1.5 cm of the right lobe and 4.3×1.4×1.0 cm of the left lobe) without nodule. After stopping of propylthiouracil therapy, he advised to monitor his thyroid function tests in the following weeks and infliximab therapy for psoriasis was continued. Four weeks later, his thyroid function tests showed elevated TSH level with a normal free T₃ and T₄ levels 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 were normal 6 weeks after the cessation of levothyroxine treatment.

Conclusion: To our knowledge, the present case is the third infliximab-induced transient destructive thyrotoxicosis followed by hypothyroidism. Therefore, periodic follow-up of thyroid function tests is necessary during infliximab therapy.