Propylthiouracil-Associated Eosinophilic Pleural Effusion: A Case Report

We describe an unusual case of a patient with eosinophilic pleural effusion (EPE) associated with long-term propylthiouracil (PTU) administration. A 43-year-old woman was admitted to our hospital after complaining of chest pain. She had had Graves’ disease, which had been treated with PTU for 11 years. Right-sided pleural effusion was detected and the result of thoracentesis confirmed an EPE. The patient’s detailed medical evaluation failed to reveal any other cause of EPE. PTU was terminated since it was thought to be the cause. Despite withdrawal of the medication, however, the pleural effusion persisted for 6 weeks, and steroid therapy was planned for 15 days in decreasing dosages. During the control visit 10 days after the initiation of steroid therapy, no pleural effusion was observed, and the steroid was discontinued. Rechallenge with PTU produced recurrent pleural effusion. Therapy with PTU was again terminated, and treatment with methimazole and a brief course of low-dose corticosteroids were begun. Chest radiography revealed disappearance of the effusion within 10 days and it did not recur during a 1-year follow-up. To our knowledge, there is only 1 other case in the English-language literature describing EPE caused by PTU. Our report is of particular importance because it describes the development of that disorder in the 11th year of PTU treatment. It also shows that steroid therapy can be effective in treating drug-induced EPE.