Cerebral hemodynamics in the posterior circulation of patients with bacterial meningitis.

OBJECTIVES

Stenoses of the middle and anterior cerebral artery (MCA,ACA) are a clinical relevant complication of bacterial meningitis. We examined the involvement of the posterior cerebral (PCA) and of the basilar artery (BA) into the inflammatory process.

MATERIAL &

METHODS

39 unselected patients (26 men, 13 women; mean +/- SD age, 49 +/- 17 years) with bacterial (n = 37) and fungal (n = 2) meningitis underwent serial transcranial Doppler sonography recordings of the mean blood velocity (MBV) and the pulsatility index (PI) in the MCA, ACA and PCA, in the BA and in the submandibular internal carotid artery on Days 1, 3, 5, 8, 14 and 21 after admission. The results of the PCA and of the BA were compared to normal reference values and correlated to corresponding neurological signs. The criterion to assume a stenosis was: for the BA an MBV > or = 95 cm/s, for the PCA an MBV > or = 85 cm/s.

RESULTS

Compared with the controls MBV in both arteries was normal on Days 1 and 8-21, but significantly increased on Days 3 and 5. The PI was significantly increased in the BA on all days and in the PCA on Days 1 and 8-21. Stenoses of the PCA (4 of 43) and of the BA (4 of 32) remained without corresponding neurological signs, and occurred only in patients with two or more narrowed arteries of the anterior circulation (p < 0.05).

CONCLUSION

In bacterial meningitis, hemodynamic disturbances in the posterior circulation are less severe than in the anterior circulation and are clinically well tolerated.