The incidence of headaches during pregnancy is 35%. Although ruling out pre-eclampsia as a possible cause for headache is important in the pregnant population, acute sinusitis should remain on the differential as it occurs six times more frequently in pregnant women. Untreated disease can lead to rare intracranial complications such as a subdural empyema. 21-year-old female with recurring headaches at 33 weeks of gestation was diagnosed with pre-eclampsia with severe features requiring emergent caesarean section. The woman continued to have altered mental status and focal neurologic deficits after delivery. Computerized tomography head imaging demonstrated a subdural collection discovered to be an empyema due to unilateral acute sinusitis of odontogenic origin.