Cerebral Aneurysm Rupture during Pregnancy Resulting in Subdural Hematoma without Subarachnoid Hemorrhage

Subarachnoid hemorrhage is typically present in cerebral aneurysm rupture, whereas acute subdural hematoma without subarachnoid hemorrhage is rare. We herein report a case of cerebral aneurysm rupture during pregnancy resulting in acute subdural hematoma without subarachnoid hemorrhage. A 37-year-old gravida 4 para 3 pregnant woman was admitted for threatened preterm labor at 29^4/7 weeks of gestation. At 29^6/7 weeks of gestation (day -14), she developed mild left eye pain, which disappeared within one day. At 31^6/7 weeks of gestation (day 0), she developed the sudden onset of severe headache and nausea. A neurological examination revealed no abnormal findings, and analgesics ameliorated her headache. At 32^1/7 weeks of gestation (day 2), after consultations with neurosurgeons, magnetic resonance imaging showed acute subdural hematoma without subarachnoid hemorrhage. Further examinations revealed a cerebral aneurysm. Emergent clipping surgery was performed with the fetus in utero in consideration of the immaturity of the fetus and stable maternal/fetal general conditions. At 35^6/7 weeks of gestation (day 28), her headache of unknown cause recurred. Considering the maturity of the fetus, the patient underwent cesarean section with good maternal and neonatal outcomes. The absence of subarachnoid hemorrhage does not eliminate cerebral aneurysm rupture.