Limbic Encephalitis is not Rare in Children and Adolescents
We read with great interest the article about limbic encephalitis (LE) in children and adolescents by Haberlandt et al.1
In the analysis of National Hospital Discharge data, the cause of encephalitis was unknown in 60% of cases.2 We have similar experience in children. Recently, we found about half of those unknown childhood encephalitides had positive autoantibodies including anti-amphiphysin antibody that only reported in paraneoplastic LE in adults.3
Traditionally, LE is characterized by a subacute course with triadic signs, i.e., short term memory deficit, limbic seizures, and psychiatric signs, together with frequent mesial temporal hyperintensity evident on magnetic resonance imaging. Our children with positive anti-amphiphysin antibody usually presented as acute encephalopathy as the following case:
A 11-year-old boy experienced high fever and delirium on the 4th day of illness along with complex partial seizures with secondary generalizations. Phenytoin, phenobarbital, valproic acid, midazolam and propofol could not suppress the recurrent seizures. Electroencephalography showed multifocal epileptiform discharges over bilateral temporal areas. Thiopental infusion was initiated soon to a burst-suppression pattern. Cerebrospinal fluid cell count and brain computed tomogram were negative. Antiviral agent and intravenous immunoglobulin were used. Clinical seizures terminated after lidocaine infusion to 6 mg/kg/h. Serum and cerebrospinal fluid evaluations for infectious and metabolic etiologies were unremarkable. Serial brain magnetic resonance imaging studies showed hyper-intensities over both temporal lobes on T2 images. Serum for antineuronal antibodies yielded positive anti-amphiphysin antibody. After adding oral corticosteroids on various combinations of antiepileptics, the complex partial seizures were partially controlled. The patient was discharged after 4 months of admission with mild cognitive difficulty and motor disability.
We consider that, with wide screening for immune biomarkers, more and more autoimmune encephalitis may explain those unknown etiologies of encephalitides. However, a more sensitive and easy-assessed biomarker should be found to start early immunotherapy for improving their outcome.4
REFERENCES 1. Haberlandt E, Bast T, Ebner A, et al. Limbic encephalitis in children and adolescents. Arch Dis Child. 2010 Oct 19. doi:10.1136/adc.2010.183897 2. Lewis P, Glaser CA. Encephalitis. Pediatr Rev 2005;26 : 353-63 3. Pittock SJ, Lucchinetti CF, Parisi JE, et al. Amphiphysin autoimmunity: paraneoplastic accompaniments. Ann Neurol. 2005;58:96-107. 4. Florance-Ryan N, Dalmau J. Update on anti-N-methyl-D-aspartate receptor encephalitis in children and adolescents. Curr Opin Pediatr. 2010;22:739- 44.
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