Multidisciplinary Management of Adolescent Presenting with Severe Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS)

Purpose: Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) is characterized by a sudden onset of obsessive-compulsive behaviors and/or restricted food intake, accompanied by other neuropsychiatric symptoms. The condition remains underrecognized due to its broad presentation and lack of standardized diagnostic tools. We present a severe case of PANS in an adolescent male following a suspected post-infectious immune response. Observations: A 16-year-old previously healthy Hispanic male developed abrupt-onset neuropsychiatric symptoms, including catatonia, obsessive-compulsive behaviors, cognitive slowing, expressive aphasia-like symptoms, regressive behavior, and severe food restriction, after a flu-like illness. Initial infectious testing was positive for Influenza B and Mycoplasma pneumoniae. Neurologic workup, including MRI, EEG, and CSF analysis, was unremarkable. Despite extensive testing, no alternative diagnosis was confirmed. Clinical presentation met diagnostic criteria for PANS. Multidisciplinary care included psychiatric treatment, gastrostomy tube placement for nutritional support, and escalating immunomodulatory therapies, including high-dose IVIG, corticosteroids, and plasmapheresis. Improvement in motor function, OCD symptoms, and nutritional status followed plasmapheresis therapy. Conclusions and Importance: This case underscores the diagnostic complexity and therapeutic challenges of PANS, particularly in severe and functionally impairing presentations. Early recognition, exclusion of mimicking conditions, and coordinated interdisciplinary management are essential. Immunomodulatory therapy may offer benefit in refractory cases, though evidence remains limited. This report highlights the urgent need for further research to define diagnostic criteria, biomarkers, and standardized treatment protocols for PANS.