Abstract
INTRODUCTION: Post-infectious encephalitis/encephalopathy is a neurological syndrome that sometimes develops following common viral or bacterial infections. The most common form is acute disseminated encephalomyelitis (ADEM). ADEM is a demyelinating disease of the central nervous system that typically presents as a monophasic disorder associated with multifocal neurologic symptoms and encephalitis. Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is another type of severe autoimmune disorder, characterized by seizures, movement disorders and psychiatric symptoms. In general, the prognosis and long-term outcomes of both ADEM and anti-NMDAR encephalitis are favorable. Most patients show complete, albeit slow recovery over a period of one to 2 years. There are few reports of patients with these disorders showing long-term residual psychiatric symptoms. CASE PRESENTATION: We report the case of a 16-year-old Japanese male who suffered from acute post-infectious encephalitis. The patient followed an atypical recovery course, in that he showed poor rapport, lack of spontaneity and passive social withdrawal for more than 2 years after the initial symptoms. While treatment with small doses of antipsychotic drugs at the hospital had no effect on the symptoms, the patient recovered gradually over a prolonged period of five or so years. CONCLUSIONS: This case report suggests that a type of acute post-infectious encephalitis with demyelinating features, possibly ADEM or anti-NMDAR encephalitis, or an overlap between the two, can cause a prodrome of behavioral changes and long-term residual psychiatric symptoms for many months, although it is eventually associated with a good prognosis.