[An adult case of adenovirus type 3 infection presenting as clinically mild encephalitis/encephalopathy with a reversible splenial lesion and increased IL-6 levels in the cerebrospinal fluid].

A 42-year-old Japanese man with a history hepatitis C who had undergone bone marrow transplantation for Burkitt lymphoma. He visited our hospital after developing a fever and sore throat. A computed tomography scan of the chest revealed pneumonia, and the patient was admitted to our hospital. After admission, he experienced a transient alteration of consciousness. Increased IL-6 levels in the cerebrospinal fluid and brain magnetic resonance imaging revealed clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). He received steroid pulse therapy and was discharged on the 14th hospital day. A neutralization test of paired serum revealed more than 4-fold increase in the adenovirus type 3 antibody titer, and a diagnosis of adenovirus-induced pneumonia was made. MERS was suspected to be involved in the pathology of encephalitis or encephalopathy following the adenovirus type 3 infection.