Epilepsy Information

American Epilepsy Society Poster (Abst. 1.140)

Early identification of patients with pres using continuous eeg reduces the co-morbidity of sah and impacts its treatment approach

Authors: Jeffrey Politsky, Igor Ugorec, Dennis Baker, Paul Rodgers and Evan Fertig

Subarachnoid Hemorrhage (SAH) is associated with significant morbidity and mortality. Vasospasm (VSP) and delayed cerebral ischemia (DCI) are two potential direct complications of SAH. Modalities used to detect VSP and DCI include clinical exam, angiography, trans-cranial Doppler, and continuous electroencephalography (cEEG) with or without quantitative software (qcEEG). In fact, cEEG and/or qcEEG have become preferred methods to detect VSP and DCI at several institutions. One of the treatments of VSP and DCI is an increase cerebral perfusion and one of this treatment's complications is posterior reversible encephalopathy syndrome (PRES), which is often difficult to detect and may have profound neurologic sequelae if not identified and treated early. We report 6 cases of early detection of PRES using qcEEG, which necessitated adjustments in the treatment of VSP and DCI.


We present the detailed findings of 6 cases of patients with SAH-induced VSP and/or DCI, who subsequently developed PRES secondary to increased cerebral perfusion pressure aimed at treating complications of SAH.

All six patients were determined to have PRES based on qcEEG findings. Two patients were determined to have PRES because of focal sub-clinical seizure activity in posterior quadrants, whereas the other four were diagnosed because of either a shift in the pattern of irregular slowing into posterior quadrant regions, or because of the occurrence of apiculate but non-ictal patterns in posterior quadrant regions. Imaging studies confirmed the diagnosis of PRES in all six patients. PRES was treated with reductions in cerebral perfusion settings and anti-seizure medication in those with ictal findings on qcEEG.

Continuous EEG is not only useful to identify patients who develop SAH-induced VSP or DCI, but also to identify patients who have developed complications of the treatment for SAH, namely PRES. Early identification VSP and DCI can result in reduced morbidity and mortality; early identification of PRES is further expected to improve patient outcome and minimze unnecessary adjunctive treatment if identified early and treated appropriately and may obviate the need for additional diagnostic imaging.