Autoimmune encephalitis

Autoimmune encephalitis (or autoimmune encephalopathy) is a diverse group of neuro-psychiatric disorders recognized recently, presenting acutely or subacutely with alteration of consciousness, cognitive decline, seizure, abnormal movements. Associated with systemic autoimmune disorders, CNS autoimmune disorders and paraneoplastic syndromes. Pathogenesis is likely to be mediated by antibodies (Abs) to CNS proteins. The Abs are directed against membrane receptors and ion channel-associated proteins that are expressed on the surface of neurons in the CNS, such as N-methyl D-aspartate receptors and leucine-rich, glioma inactivated protein and contactin-associated protein like, that are associated with voltage-gated potassium channels. The diseases are not invariably cancer-related and are therefore different from the classical paraneoplastic neurological diseases that are associated with, but not caused by, Abs to intracellular proteins. Diagnosis of autoimmune encephalopathy is based on the clinical course, serologic evidence of autoimmunity, severe but nonspecific slowing on electroencephalography, and evidence of intrathecal inflammation in the cerebrospinal fluid and neuroimaging by MRI. Treatment include first-line steroids, intravenous immunoglobulins(IVIG), and plasma exchange, and second-line Rituximab and Cyclophosphamide, followed in many cases by steroid-sparing agents in the long-term.