Epilepsia Partialis Continua in an Adolescent: A Case of Diagnostic Overshadowing.

Abstract

Epilepsia partialis continua is an uncommon form of focal status epilepticus characterized by continuous focal motor activity with preserved awareness. In adolescents with psychiatric comorbidity, these movements may be mistaken for functional or compulsive behavior, a phenomenon that may reflect diagnostic overshadowing, the misattribution of neurological or medical symptoms to a preexisting psychiatric condition. A 15-year-old boy with anxiety disorder, obsessive compulsive disorder, and panic disorder presented with a two week history of persistent right toe and foot tapping that spread proximally and became painful. His family reported that the movements continued during sleep, although inpatient observation showed that they occasionally paused or disappeared. This inconsistency contributed to an early impression of a psychogenic process and led to the deferral of neuroimaging. Continuous video EEG subsequently demonstrated frequent, rapidly recurring epileptiform discharges over the left central region that corresponded to the right foot movements, confirming epilepsia partialis continua. Treatment with lacosamide and clobazam led to complete resolution of the movements and pain within 24 hours. Subsequent brain MRI was unremarkable, and symptoms remained controlled on follow up. This case illustrates how psychiatric history can shape diagnostic reasoning and delay recognition of epilepsia partialis continua. Persistent focal motor activity, even when intermittently suppressible or behaviorally ambiguous, should prompt early consideration of this diagnosis and escalation to prolonged video EEG when routine evaluation is inconclusive, enabling accurate diagnosis and effective seizure control.