**4.2 Scoring system**

Several scoring systems have been developed to predict patient outcomes for those with aneurysm related sub-arachnoid hemorrhage (a-SAH). The Hunt and Hess score and World Federation of Neurological Surgeons grading system are both used to predict patient outcome, and the Fisher grade helps to predict vasospasm [80, 81].

The severity of neurologic impairment and the amount of subarachnoid bleeding on admission are the strongest predictors of neurologic complications and outcome [82]. Therefore, it is essential that patients with SAH be scored promptly after arrival and stabilization. The World Federation of Neurological Surgeons Scale (WFNSS) and the modified Fisher Scale are the most reliable and simple to perform [74, 75]. Higher WFNSS and modified Fisher Scale scores are associated with worse clinical outcome and a higher proportion of neurologic complications. The modified Fisher scale is designed to predict the development of delayed cerebral ischemia (DCI) which is the most common cause of disability secondary to rupture next the actual rupture itself (**Tables 1**–**3**).
