Abstract
A massive unilateral pleural effusion developed in a 52-year-old female with severe motor and intellectual disabilities. A high concentration of eosinophils in peripheral blood and pleural fluid was observed, leading us to suspect a drug-induced pleural effusion. She had been using dantrolene sodium for 27 years for her spasticity. The pleural effusion disappeared several months after discontinuing dantrolene therapy. This drug is commonly used for patients with severe motor and intellectual disabilities. Therefore we recommend systematic, regular, and careful clinical examinations. When the etiological factors are unclear, we should consider a drug-induced pleurisy due to drugs, including dantrolene.
