Claude Bernard-Horner syndrome resulting from pleural empyema.

Claude Bernard-Horner syndrome presents various etiologies and occurs as the direct result of interrupted nerve signaling at any point along the nerve trajectory, be it intrathoracic or extrathoracic. Herein, we report a case of Claude Bernard-Horner syndrome caused by loculated pleural empyema located in the paravertebral region of the upper third of the right hemithorax. The patient was submitted to thoracotomy in order to drain the infected fluids. The end result was satisfactory, including resolution of the infection, pulmonary expansion, and remission of the syndrome.