CSF hydrodynamics after subarachnoid hemorrhage.

Recent reports have shown that despite an apparently satisfactory recovery from previous subarachnoid hemorrhage (SAH), many patients still have minor sequelae when specifically looked for. The cause of this so-called post-SAH-encephalopathy is uncertain. This prospective study comprises 54 patients who underwent aneurysmal surgery after SAH between September 1978 and March 1985. One patient died, and 6 patients were non-biased drop-outs. CSF hydrodynamics, determined by infusion test and isotope cisternography, were evaluated on the remaining 47 patients in the recovery stage. Five patients (11%) were found to have typical clinical, CSF dynamic and radiological manifestations of normal pressure hydrocephalus (NPH), and all were shunted with good results. Twelve (26%) had abnormal results consistent with disturbed CSF-hydrodynamics, although there were no clinical or radiological findings supporting the diagnosis of shunt-demanding NPH. Disturbed CSF-hydrodynamics as one of the possible etiological factors of post-SAH-encephalopathy is discussed.