Alteration of cerebral blood flow in patients with bacterial and viral meningoencephalitis.

PURPOSE Our purpose was to investigate cerebral blood flow disturbances in patients with bacterial and viral meningoencephalitis. METHODS Forty-two patients with acute bacterial and viral meningoencephalitis and 14 control subjects were studied using 99mTc-hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography (SPECT). SPECT images were evaluated semiquantitatively. The results were compared with clinical severity of the meningoencephalitis assessed at the time of the SPECT study with the Hunt and Hess scale, with separately recorded focal clinical signs, and with the Glasgow outcome scale (GOS) after 3 weeks. RESULTS Count density values were significantly reduced in patients with bacterial meningoencephalitis as compared with the control subjects. Inhomogeneous tracer accumulation assessed by asymmetry indexes was significantly greater in patients than in the control group. With increasing Hunt and Hess scores, the count density values decreased and the asymmetry indexes increased. Patients with a poor outcome (GOS 1 to 3) had significantly higher asymmetry indexes and lower CDV values than did patients with a good outcome. CONCLUSION Global and focal alterations of cerebral perfusion are frequent in bacterial and viral meningoencephalitis and correlate with acute clinical state.