Anti-N-methyl-D-aspartate receptor encephalitis during relapse of herpes simplex encephalitis in a young boy: A brief review of literature

Magnetic resonance imaging (MRI) of the brain showed asymmetrical abnormal signal intensity involving bilateral frontal, precentral and central subcortical white matter, deep gray and white matter, bilateral ventrolateral thalami, and left midbrain and pons along the corticospinal tracts [Figure 1]a and [Figure 1]b. The electroencephalogram (EEG) revealed diffuse encephalopathy. Repeat MRI of the brain revealed scarred cortices with a large area of gliosis in bilateral frontoparietal perirolandic cortical and subcortical white matter as well as bilateral thalamocapsular region with subtle gyral enhancement and significant regression in the extent of restricted diffusion seen in the previous study [Figure 1]c and [Figure 1]d. Then, he was given intravenous methylprednisolone therapy for 3 days followed by oral prednisolone (2 mg/kg/day), to which he showed gradual improvement. [2],5,[8],[9],[10],[11],[12],[13],[14],[15],[16] Association of autoantibodies in post-herpes simplex encephalitis neurological relapse Pruss et al., in their study on acute serum samples of adult patients with HSE, found 30% of patients with serum positivity for NMDAR antibodies of IgA, IgG, and IgM subtypes.