Hematoma expansion caused by trapped cerebrospinal fluid in subacute phase intracerebral hemorrhage: A case report.

Background: Although hematoma expansion (HE) is caused by active bleeding in patients with intracranial hemorrhage in most cases, cerebrospinal fluid (CSF) trapped in the hematoma cavity is not a well-known cause of HE.

Case Description: We present a case of subcortical hemorrhage in an 80-year-old woman who experienced neurological deterioration in the subacute phase because of HE caused by CSF pooling in the hematoma cavity. The patient was transferred to our hospital from a previous hospital for surgical treatment because the consciousness disturbance was likely caused by the perihematomal edema that occurred 4 days after onset. Head computed tomography (CT) at admission to our hospital showed a blend sign, and a part of the low-density area of the hematoma was enlarged compared with the CT at admission to the previous hospital. Although the hematoma was located adjacent to the lateral ventricle, no intraventricular hemorrhage was observed. Emergent hematoma evacuation was performed, and intraoperative findings indicated that the enlarged hematoma cavity was caused by CSF pooling. The patient's postoperative course was uneventful. She was transferred to a rehabilitation hospital 16 days after admission to our hospital.

Conclusion: Hematomas adjacent to the ventricle and showing a blend sign can expand in the subacute phase because of the trapped CSF.