Abstracts

Rationale: We previously reported that sleepiness that arises as an adverse effect of antiepileptic drugs is causally related to prolonged blood-brain barrier (BBB) dysfunction in patients that develop epilepsy after encephalitis/encephalopathy (EAE) (Mogami Y, Takahashi Y, et al., 2012). The cerebral spinal fluid (CSF)/serum albumin ratio (albumin quotient, QAlb) is often used as a measure of BBB permeability. To examine chronic BBB dysfunction in patients with EAE, we compared the QAlb of epilepsy patients with various etiologies. Methods: We analyzed CSF samples from 430 patients, who agreed to undergo CSF examinations as part of the diagnostic workup for refractory epilepsy at our center between 2004 and 2015. We excluded samples of cases involving traumatic taps, and selected 216 samples from patients whose epilepsy etiologies included unknown cause (UC, n=101), EAE (n=68), Rasmussen syndrome (RS, n=25), and focal cortical dysplasia (FCD, n=22). We compared the mean QAlb of the FCD patients with those of the other groups. The normal BBB group (nBBB) was composed of epilepsy patients with etiologies other than EAE or RS. Results: The mean QAlb of the patients with EAE (meanSD: 4.22.0) and RS (3.71.7) were higher than those of the patients with FCD (2.71.0) (EAE, p < 0.001; RS, p=0.042). Linear regression analyses suggested that QAlb was moderately and weakly correlated with age in the EAE patients (y=0.139x+2.81, n=68, r=0.53, p < 0.001) and nBBB group (y=0.055x+2.68, n=123, r=0.37, p < 0.001), respectively. Linear regression analyses also suggested that QAlb was moderately and weakly correlated with disease duration in the EAE patients (y=0.245x+3.47, n=68, r=0.45, p < 0.001) and nBBB group (y=0.074x+2.87, n=123, r=0.31, p < 0.001), respectively. In each case, the y-intercept and slope of the abovementioned correlations were higher in the EAE patients than in the nBBB group. Conclusions: Our study suggests that patients with EAE have higher levels of chronic BBB dysfunction and that their conditions continue to worsen. We consider that this prolonged increase in BBB dysfunction contributes to the clinical manifestations of patients with EAE. Funding: The author received no financial support for the research, and/or authorship of this abstract.