Uncommon but consequential: remote cerebral and cerebellar hematomas, and pseudohypoxic brain swelling following epilepsy surgery.

INTRODUCTION

Epilepsy surgery is an effective treatment for drug-resistant epilepsy but carries the risk of uncommon yet potentially serious postoperative complications. Among these, remote intracranial hemorrhage (RIH), encompassing remote cerebral and cerebellar hematomas, and pseudohypoxic brain swelling (PHBS) are rare entities that have been hypothesized to be related to excessive cerebrospinal fluid (CSF) drainage. Data on these complications in epilepsy surgery remain limited, and their combined presentation within the same surgical cohort has not been widely documented.

METHODS

We retrospectively reviewed patients aged ≥ 18 years who underwent resective or palliative epilepsy surgery (excluding vagal nerve stimulation) between January 1995 and March 2024 at our tertiary epilepsy center. Patients with postoperative remote parenchymal hematomas and/or imaging findings consistent with PHBS were identified. Clinical, surgical, radiological, and follow-up data were analyzed.

RESULTS

Among 682 patients, three (0.4%) developed RIH and two (0.29%) developed PHBS in the early postoperative period. RIH cases followed temporal lobectomy or hemispherotomy and demonstrated typical neuroimaging features, including the cerebellar "zebra sign." All had normal preoperative coagulation profiles, an intraoperative drain in place, and favorable long-term neurological outcomes. PHBS cases occurred after subdural and/or depth electrode placement, showing MRI features of the lentiform fork sign and deep nuclear involvement. Notably, one of the two PHBS cases exhibited a distinctive, previously undescribed postoperative EEG finding, abundant triphasic wave discharges involving the bilateral anterior regions with left-sided predominance, which, along with the MRI abnormalities in both cases, resolved completely during follow-up.

CONCLUSION

RIH and PHBS are rare but clinically significant complications of epilepsy surgery. Our series is the first to describe reversible EEG and MRI changes in PHBS, presented alongside RIH cases that may share overlapping pathophysiological mechanisms. Early recognition, cessation of CSF drainage when suspected as a contributing factor, and close monitoring are essential to optimize patient outcomes.