Pediatric autoimmune encephalitis

Autoimmune (antibody mediated) encephalitis (AE) is emerging as a more common cause of pediatric encephalopathy than previously thought. The autoimmune process may be triggered by an infection, vaccine, or occult neoplasm. In the latter case, onconeural autoantibodies are directed against intracellular neuronal antigens, but a recent heterogeneous group of encephalitic syndromes has been found not to have underlying tumor but is associated with autoantibodies to the neuronal surface or synaptic antigens. Neuropsychiatric symptoms are very common in autoimmune encephalopathy; as a result, affected children may be initially present to psychiatrists. Neurological features are movement disorders, seizures, altered conscious level, and cognitive regression. Hypoventilation and autonomic features may be an aspect. Inflammatory findings in the cerebrospinal fluid may be present but are relatively nonspecific. Magnetic resonance imaging (MRI) may also demonstrate abnormalities that provide clues for diagnosis, particularly on fluid-attenuated inversion recovery or T2-weighted images. AE is well responsive to immune therapy, with prompt diagnosis and treatment strongly beneficial. Patients with paraneoplastic encephalitis are more refractory to treatment compared to those in whom no malignancy is identified. Herein, the authors present an update of literature data on the clinical presentation, laboratory and imaging findings, therapy, and outcomes for the most common autoimmune encephalitides.