Acute disseminated encephalomyelitis developed after acute herpetic gingivostomatitis

A child with acute disseminated encephalomyelitis (ADEM) developed after acute herpetic gingivostomatisis was described. Inspite of the improvement of his gingivostomatitis, his consciousness gradually deteriorated and he was admitted to Nakadori General Hospital. His consciousness level was drowsiness and increased bilateral patellar reflexes were shown. Because magnetic resonance imaging (MRI) T2-weighted scan showed areas of high signal intensity disseminated in superior portion of medulla oblongata, dorsal portion of pons, basal nuclei and thalamus, he was suspected as having ADEM. Anti-herpes simplex virus (HSV) 1 IgG and IgM antibodies elevated in both blood and cerebrospinal fluid. From these results, HSV1 infection was thought to be the preceding infection of ADEM. Methylprednisolone therapy (20 mg/kg daily) for 3 days, followed by prednisolone (2 mg/kg) was started, with an excellent response. In addition, administration of acyclovir was also continued, considering the complication of HSV encephalitis. MRI T2-weighted scan performed at 2 months later after the onset of ADEM revealed disappearance of the lesions. He was discharged without remaining disorders. It is difficult to distinguish between ADEM and HSV encephalitis because both of these diseases show various neurological symptoms. In our case, MRI was the most useful method for correct diagnosis of ADEM. We concluded that ADEM is important as a disease of central nervus system due to HSV1 infection, in addition to encephalitis.