Abstracts

Rationale: Rasmussen Encephalitis (RE) is a rare cause of medically intractable epilepsy that usually affects children and adolescents. It is a chronic inflammatory disease characterized by progressive hemiplegia, cognitive deficits, and unilateral brain atrophy. The Pardo grading scale is a clinical tool to characterize the profile of cortical involvement. The grading scale ranges from 0 (normal cortex) to 4 (end stage cortical disease). There is limited data describing the pathology and how it correlates to seizure outcome. Our goals were to determine the relationship between the severity of pathology and seizure outcome in RE patients who underwent surgery at the Cleveland Clinic and to look at severity of disease to see if it correlates with severity of pathology.

Methods: Data on the pathology and clinical variables were retrospectively collected and reviewed. The seizure outcome was measured by determining Engel class. The pathology was grouped into Pardo stage 0-2 (less severe) and Pardo stage 3-4 (more severe). We assessed the following clinical variables: duration of epilepsy, number of failed antiepileptic drugs (AEDs), presence of epilepsia partialis continua (EPC) preoperatively, presence of hemiparesis preoperatively, severity of hemiparesis (mild to moderate or severe), duration of hemiparesis, and presence of bilateral MRI abnormalities preoperatively. Our redo hemispherectomy cases were looked at separately.

Results: We obtained tissue specimens from 34 samples after hemispherectomy for review. No patients were Pardo stage 0, sixteen were stage 1, three were stage 2, two were stage 3, and thirteen were stage 4. There was no statistically significant correlation between Pardo staging and seizure outcome (p value = 1). There was a statistically significant correlation between Pardo stage and duration of epilepsy (p = .009) and duration of hemiparesis (p = .008). The other variables failed to reach statistical significance. In our redo cases, on final pathology all 5 patients were in the more severe pathology group, and all were Engel class I.

Conclusions: Consistent with the progressive nature of RE, more severe pathology was associated with a longer duration of epilepsy and longer duration of hemiparesis. Results from this series suggest the degree of cortical involvement with RE as assessed on surgical histopathology does not correlate with seizure outcome after hemispherectomy, and likely not helpful for prognostication about long-term outcome, which appears to be more dependent on surgical technique/complete disconnection.

Funding: Please list any funding that was received in support of this abstract.: N/A.