RESUMO
INTRODUCTION: Isolated acute sphenoid sinusitis is an uncommon sinus infection, frequently misdiagnosed and not usually considered in the differential diagnosis of acute severe headache, with the potential of serious neurologic complications. AIM: Describe four patients with acute sphenoid sinusitis who presented with acute onset of severe headache and consider the role of medical or surgical management. Two patients do not required surgical intervention and medical treatment was sufficient. One patient had sphenoidotomy due to meningitis. One patient was performed surgical intervention after fail of medical therapy. Acute isolated sphenoid sinusitis appears to be difficult to diagnose. It is important to be aware of acute sphenoid sinusitis in the setting of new onset severe headache, when imaging studies are unrevealing for intracranial pathology. Medical therapy focused on infection, inflammation, and obstruction may be adequate for resolution, but surgical intervention may be required in certain situations.