Expanding the clinical spectrum of pediatric CASPR2 antibody-associated autoimmune encephalitis: a multicenter case series
Introduction Contactin-associated protein-like 2 (CASPR2) antibody-associated autoimmune encephalitis is rare in children, and available clinical data are limited. Our aim is to describe the clinical spectrum, diagnostic findings, treatment, and outcomes of all pediatric CASPR2 antibody-associated encephalitis patients reported in Hungary. Methods We present a retrospective case series including nine pediatric patients diagnosed with CASPR2 antibody-associated encephalitis across five centers. Clinical, laboratory, imaging, electrophysiological findings, treatment, and follow-up data were collected. Results The mean age at onset was 4.1 ± 2.6 years. All patients were serum CASPR2 antibody-positive; two had CSF positivity. The most common symptoms included sleep disorder, irritability, aggressiveness, hypertension, tachycardia, abdominal pain, itching, exanthema, and weight loss. No specific abnormalities were detected on MRI, EEG, or laboratory testing. Immunotherapy led to favorable outcomes in nearly all patients, with one relapse during follow-up. Discussion This series expands the clinical spectrum of CASPR2-associated autoimmune encephalitis in children. The presenting symptoms in pediatric patients may differ not only from those observed in adults but also from other forms of autoimmune encephalitis. The diagnostic process is especially complex due to the variability and age-related evolution of clinical manifestations, which can be difficult to recognize in younger children and commonly contribute to diagnostic delay. Early recognition and immunotherapy are associated with favorable prognosis. This case series underscores the importance of recognizing the diverse spectrum of presenting symptoms and highlights the need for raising awareness of the clinical variability. Larger prospective studies are needed to define diagnostic, therapeutic strategies and prognostic factors in the pediatric population.