RELATION BETWEEN CHANGE IN Ca AND Mg LEVELS OF CEREBROSPINAL FLUID AFTER SUBARACHNOID HEMORRHAGE AND THE OCCURRENCE OF VASOSPASM

Cerebral vasospasm is a characteristic complication after subarachnoid hemorrhage (SAH), and the onset of vasospasm is a very important factor to decide the patient's outcome. Though various causal factors have been proposed for cerebral vasospasm after SAH, none of them explain the whole pathomechanism of vasospasm. To evaluate the role of trace elements in vasospasm, we have examined the sequential change in element concentration in the cerebrospinal fluid (CSF) after SAH by PIXE, and have investigated the relation between trace elements and vasospasm. We obtained the CSF samples from cisternal drainage of 17 patients with SAH who underwent radical surgery within 48 hours from the onset. The drainage was placed into basal cisterns at the end of the operation. Three sampling times (3-5, 7-9 and 12-14 days from the onset) were scheduled, because vasospasm is likely to occur from day 4 through day 14 after the onset. Cerebral angiograms were performed to classify vasospasm on day 1 and 7 after the onset. We measured 29 elements in the CSF and focused on Ca and Mg levels in this study, since Ca -influx into the smooth muscle cells is a principal mechanism of muscle contraction, and the competition between Ca and Mg is closely related to the muscle contraction. We found a significantly lower levels of Mg in the CSF of patients with vasospasm on days 7-9 after the onset. These results suggest that Mg in the CSF possibly ameliorate vasoconstriction due to Ca in the pathomechanism of vasospasm.