Pupillary Dilation in an Adolescent With Psychogenic Non-epileptic Seizures: A Case Report.

Psychogenic non-epileptic seizures (PNES) are functional episodes that mimic epileptic seizures without epileptiform activity. We describe a 16-year-old female with trauma history, mood disorder, and a recent suicide attempt who developed recurrent PNES during hospitalization. Episodes featured unresponsiveness, irregular shaking, and heightened sympathetic arousal with tachycardia, hypertension, diaphoresis, and pupillary dilation up to 8 mm. Events were often prolonged or clustered and triggered by environmental stressors. Given concerns for epileptic seizures, the patient underwent medical evaluation, which revealed no epileptiform activity captured on video-electroencephalogram during events and was consistent with a diagnosis of PNES. Management included monitoring, sertraline titration, and behavioral strategies such as mindfulness techniques and minimizing unnecessary staff interventions during episodes. By discharge, the patient no longer endorsed suicidal ideation; had shown a reduction in frequency and severity of PNES episodes; and was motivated to continue care. This case highlights pupillary dilation as an underrecognized finding in PNES and underscores the need for further study to clarify its prevalence, mechanisms, and diagnostic implications.