Differentiation of psychogenic nonepileptic attacks from status epilepticus among patients intubated for convulsive activity

Abstract

Background and objective: Patients with psychogenic nonepileptic attacks (PNEA) sometimes receive aggressive treatment leading to intubation. This study aimed to identify patient characteristics that can help differentiate PNEA from status epilepticus (SE). Methods: We retrospectively identified patients with a final diagnosis of PNEA or SE, who were intubated for emergent convulsive symptoms and underwent continuous electroencephalography (cEEG) between 2012 and 2017. Patients who had acute brain injury or progressive brain disease as the cause of SE were excluded. We compared clinical features and laboratory values between the two groups, and identified risk factors for PNEA-related convulsive activity. Results: Over a six-year period, 24 of 148 consecutive patients (16%) intubated for convulsive activity had a final diagnosis of PNEA rather than SE. Compared to patients intubated for SE, intubated PNEA patients more likely were <50 years of age, female, white, had a history of a psychiatric disorder, had no history of an intracranial abnormality, and had a maximum systolic blood pressure <140 mm Hg (all P < 0.001). Patients with 0–2 of these six risk factors had a 0% (0/88) likelihood of having PNEA, those with 3–4 had a 15% (6/39) chance of having PNEA, and those with 5–6 had an 86% (18/21) chance of having PNEA. Sensitivity for PNEA among those with 5–6 risk factors was 75% (95% CI: 53–89%) and specificity was 98% (95% CI: 93–99%). Conclusions: In the absence of a clear precipitating brain injury, approximately one in six patients intubated for emergent convulsive symptoms had PNEA rather than SE. Although PNEA cannot be diagnosed only by the presence of these risk factors, these simple characteristics could raise clinical suspicion for PNEA in the appropriate setting. Urgent neurological consultation may prevent unnecessary intubation of this at-risk patient population.