Clinical overlap of functional neurologic symptom disorder and complex regional pain syndrome in pediatrics: A case report

Abstract

This case study documents a 13-year-old female who presented to our intensive inpatient chronic pain rehabilitation program with complex regional pain syndrome (CRPS) of her left leg, which was significantly interfering with her normal daily functioning. She participated in a full day of traditional interdisciplinary therapies, including physical and occupational therapy for 3 hours daily. As assistive equipment was altered or weaned her physical mobility, balance, and tremors worsened and/or increased. As she began advancing her legs more independently (versus requiring physical assist), she demonstrated more variable functional strength and stability, inconsistent balance reactions, and a more unsteady gait pattern. The team was treating her according to her incoming CRPS diagnosis; however, as treatment progressed, her physical and psychological presentation seemed more aligned with diagnostic criteria of functional neurologic symptom disorder (FND). Staff then treated according to the FND diagnosis resulting in successful long-term outcomes. The clinical impact from this case study includes highlighting the commonalities between CPRS and FND clinically, discussing treatment suggestions depending on the diagnosis, and emphasizing key components of family/patient education.