Autoimmune encephalopathies in children: clasifi cation, diagnosis and treatment

Autoimmune encephalopathies are clinically manifested as limbic or diff use encephalitis. According to the etiology, they are classified as paraneoplastic and non-paraneoplastic. Signs and symptoms of autoimmune encephalitis are variable. The symptomatologycommonly includes headache and epileptic attacks often progressing to epileptic status, movement disorders (ataxia, dyskinesias,chorea, dystonia and tremor), behavior changes, cognitive impairments, psychoses and various degrees of disorders ofconsciousness. Faciobrachial dystonic seizures can precede the development of limbic encephalitis. Autonomic dysfunction, sleepdisorders and hypoventilation are often present. The development of autoimmune encephalopathies can be induced by eithertumor or viral antigens. However, in a signifi cant number of cases, disease triggers remain unidentifi ed. According to the localizationof target antigens, autoimmune encephalopathies can be divided into those caused by antibodies against intracellular antigens(Ma2,Hu) and those caused by antibodies against cell surface antigens, i.e. synaptic antigens (N-methyl-D-aspartate receptor(NMDAR), voltage-gated potassium channel complex/LGI1). The former are paraneoplastic in origin, more often in adults andrespond poorly to immunotherapy. The latter ones can aff ect children as well, and are usually-responsive to immunotherapy. Antibodiescan be detected in both cerebrospinal fl uid and serum. Mild pleocytosis and/or oligoclonal bands can be found in cerebrospinalfl uid but in some patients the cerebrospinal examination fi ndings can be completely normal. The electroencephalography fi ndingconsists of diff use, slow dysrhythmic encephalopathic changes or so-called extreme delta brushes and focal epileptogenicchanges, i.e. paroxysmal bursts in case of limbic encephalitis. Magnetic resonance image fi nding of the brain is usually normal orpresents transient sub/cortical hyperintensities in T2-weighted images but is signifi cant for the diagnosis of limbic encephalitis.Early recognition of autoimmune encephalopathy is of utmost importance because of the need of proper diagnostic procedure andtimely introduction of appropriate therapy.
Keywords: encephalopathies; autoimmune encephalitis; electroencephalogram; NMDA receptor; synaptic antigens, pediatric
Category: Review
Volume: Vol. 58, No 4, october - december 2014
Authors: N. Barišić, N. Vrsaljko, V. Zvonar, G. Tešović
Reference work: Paediatr Croat. 2014;58:270-7

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