Acute limbic encephalitis with focal hyperperfusion on single photon emission computed tomography

Here we report an 11-year-old boy with acute encephalopathy with neuropsychiatric symptoms. The patient had mildly decreased consciousness, delirious behavior, and affective changes next day of fever onset. Hematologic, biochemical, and metabolic examinations were unremarkable. CSF analysis revealed cell counts of 278 cells/mm(3) and a protein level of 87 mg/dL. Although MRI revealed no abnormal findings, an increase in regional cerebral blood flow was present in the bilateral frontal lobes, mesial temporal lobes, and basal ganglia on single photon emission computed tomography. The measurement of the concentrations of biomarkers such as cytokines in the patient's serum and cerebrospinal fluid revealed elevated levels of IL-4 and TNF-α in the cerebrospinal fluid. Immunohistochemical studies applying control human brain sections did not demonstrate the presence of autoantibodies. We considered that innate immunity rather than autoantibody response may have contributed to the neuropsychiatric symptoms of our patient. These results suggest heterogeneity of patients with acute encephalopathy with neuropsychiatric symptoms.