Nonvasculitic autoimmune inflammatory meningoencephalitis imitating Creutzfeldt-Jakob disease.

BACKGROUND Nonvasculitic autoimmune inflammatory meningoencephalitis and Creutzfeldt-Jakob disease can present as rapidly progressive encephalopathies with similar clinical features. Slowing of background rhythm is an electroencephalographic characteristic shown by both, but persistent periodic sharp waves are more specific for Creutzfeldt-Jakob disease and have not been reported in nonvasculitic autoimmune inflammatory meningoencephalitis or related autoimmune meningoencephalitides. OBJECTIVE To describe a patient with clinical (rapidly progressive myoclonus, dementia, and Parkinsonism) and electroencephalographic findings (persistent periodic sharp waves) that diagnostically suggest Creutzfeldt-Jakob disease. DESIGN AND SETTING A case report at the Mayo Clinic Arizona, Scottsdale. RESULTS The patient made a dramatic recovery with resolution of the periodic sharp wave complexes after treatment with high-dose corticosteroids. Our case is the first reported case of a patient with probable nonvasculitic autoimmune inflammatory meningoencephalitis and electroencephalographic periodic complexes suggestive of Creutzfeldt-Jakob disease. CONCLUSION Rapidly progressive encephalopathy with periodic sharp wave complexes can be associated with a reversible autoimmune syndrome.