Risk factors of chronic shunt dependent hydrocephalus following aneurysmal subarachnoid haemorrhage.

Background: Acute and delayed hydrocephalus are common sequelae following aneurysmal subarachnoid haemorrhage.

Aims: To identify factors that may influence cerebrospinal fluid diversion either temporarily or permanently in order to guide clinical judgement.

Methods: Patients treated in our unit between 01/2014 until 12/2017 with aneurysmal SAH were retrospectively analysed to identify significant factors predisposing to CSF diversion.

Results: 242 patients were analysed (180F, 62M) with mean age 56 years over 36 months. 31 % patients had EVD inserted and 12 % received shunts. 19 patients had EVDs prior to their shunt. 11.8 % patients received serial lumbar puncture. Higher WFNS (P<0.05) and Fisher grade (P<0.05) were associated with increased rates of EVD insertion and shunting. Higher WFNS and Fisher scores were observed within posterior circulation aneurysms. Lower GCS and higher WFNS had significant correlation towards early shunting (P<0.05). EVD infection predisposes to higher rates of shunt conversion (P<0.05). Factors predisposing to post aneurysmal subarachnoid haemorrhage hydrocephalus and CSF drainage included aneurysm location in posterior circulation (P<0.05), increasing relative need of EVD insertion by 185 % and shunting by 240 %. Basilar tip aneurysms had even higher incidence of shunting (42 % of all posterior circulation aneurysms). Posterior circulation aneurysms had significantly higher risk of requiring EVD insertion, with 48 % of aneurysms in the posterior circulation compared to 25 % in the anterior circulation requiring EVDs (P<0.05). Incidence of posterior circulation aneurysms increases with age (>50(P<0.05)).

Conclusion: Our study demonstrated factors that may predict chronic post aneurysmal subarachnoid haemorrhage hydrocephalus (PASHH) in patients that will ultimately need timely intervention.