Unilateral hyperfusion in brain-perfusion SPECT predicts poor prognosis in acute encephalitis.

We studied 88 patients with acute encephalitis using hexamethylpropyleneamine oxime and single photon emission computed tomography (SPECT). All patients had been initially treated with intravenous acyclovir. The etiology could be disclosed in 37 patients (42%), which included 15 patients with herpes simplex encephalitis, 7 with varicella-zoster encephalitis, and 29 with other encephalitides (Mycoplasma, adenovirus, influenza, rotavirus, rubella, Epstein-Barr, arbovirus, syphilis, and tuberculosis). Unilateral hyperperfusion in SPECT was an independent predictor of poor prognosis, whereas neither clinical outcome variables, such as seizures, state of consciousness, and focal neurologic findings, nor CSF or EEG findings were not. Focal unilateral hyperperfusion is an indicator of severe inflammation of the brain tissue and predicts a poor outcome as assessed in terms of activities of daily living after recovery.