An 11-year-old boy with fever and pain in the left forehead and the left orbit was diagnosed as sinusitis by plain X-ray and CT scan. Antibacterial therapy with ABPC followed by CPR and CLDM did not improve the symptoms. Examination of cerebrospinal fluid revealed pleocytosis. Numbness began to appear in the right extremities, and MRI findings of fluid collection in the anterior and the temporal area led us to diagnose his illness as subdural empyema. He underwent cerebral decompression and irrigation of the empyema cavity. He recovered and was discharged 76days after admission. The importance of prompt diagnosis by CT scanning or MRI is discussed when fever persists in patients with sinusitis.
