Objective:

NA

Background:

Pediatric seronegative autoimmune encephalitis (AE) with status epilepticus is an increasingly recognized clinical challenge requiring prompt treatment. A subset of cases may have an as-yet-unrecognized underlying neural autoantibody. While paraneoplastic neurological disorders are rare in children, a high degree of suspicion is required in pediatric AE.

Design/Methods:

Case report

Results:

A 23-year-old female with progressive neurobehavioral regression, cerebellar degeneration, and intractable epilepsy presented at age 13 in super-refractory status epilepticus. Brain MRI showed cerebellar and left posterior parahippocampal atrophy with bilateral mesial temporal lobe T2/FLAIR hyperintensities. Cerebrospinal fluid revealed lymphocytic pleocytosis and elevated protein. After extensive evaluation, she was diagnosed with probable AE. Further diagnostic testing revealed a novel neural-restricted antibody in both her serum and CSF at ages 9, 10, and 13, with strong purkinje cell binding affinity. PET/CT revealed an FDG-avid left adrenal mass, previously found to be hormonally inactive and incidental on screening kidney ultrasound three years prior. Resection led to robust clinical improvement, enabling successful weaning off anesthetics. Pathology revealed a benign ganglioneuroma. At discharge, her seizure frequency decreased to brief daily focal seizures controlled with anti-seizure medications and immunotherapy.

Conclusions:

Early recognition and treatment of pediatric AE is critical, even in the absence of known autoantibody seropositivity. Incidentally found and benign-appearing tumors in this population should be further evaluated and considered for resection if the suspicion for a paraneoplastic AE is high. Looking for and identifying novel antibody-associated syndromes can therefore help guide management decisions, clarify the underlying etiology, and facilitate targeted treatment.