A child who suffered from HSV encephalitis and AE with positive anti-MOG results: a case report.

Objective: To investigate the clinical manifestations of a pediatric case involving herpes simplex virus (HSV) encephalitis concurrent with autoimmune encephalitis (AE), which is characterized by a positive anti-myelin oligodendrocyte glycoprotein (MOG) antibody status.

Results: A 12-year-old girl initially presented with symptoms of autoimmune encephalitis, including weakness and poor appetite, followed by headache, dizziness, and personality changes, which are indicative of disease progression. Cerebrospinal fluid routine biochemical tests demonstrated abnormal results. Cerebrospinal fluid mNGS results demonstrated human herpesvirus type I, and autoimmune encephalitis antibody tests suggested a positive result for anti-myelin oligodendrocyte glycoprotein (MOG) antibodies (1:100). Brain MRI revealed abnormal signals in the bilateral frontal lobes and dorsal thalamus. Therefore, diagnoses of herpes simplex virus encephalitis and autoimmune encephalitis were determined. After treatment with acyclovir, gamma globulin and hormones, the patient exhibited significant improvement in her symptoms.

Conclusions: Children with herpes simplex virus encephalitis combined with autoimmune encephalitis may present with atypical clinical symptoms, and a positive anti-MOG antibody test is rarely observed, with no previous reports on this occurrence. The early detection of the relevant pathogens (in addition to timely reevaluation) can aid in accurate diagnosis. Moreover, antiviral and immunosuppressive therapy may significantly improve symptoms and patient prognosis.