Utility of lumbar puncture after a normal brain computed tomography scan in patients presenting to the emergency department with suspected subarachnoid haemorrhage: A new more rational approach?

Abstract

Objective The diagnostic approach for patients presenting to EDs with headaches suspicious for subarachnoid haemorrhage (SAH) remains challenging. Modern third‐generation computed tomography (CT) has been shown to be extremely sensitive in identifying SAH and may eliminate the need for lumbar puncture (LP) which is an invasive, time‐consuming procedure with limited accuracy and complications. The aim of this study is to assess the utility of LP in patients being evaluated for possible SAH in the ED after a negative non‐contrast CT scan of the brain, as well as addressing the knowledge gap in regard to rational diagnostics among clinicians. Methods We conducted a retrospective data analysis of patients being evaluated for possible SAH between June 2013 and June 2018 across three EDs in Victoria, Australia. A diagnosis of SAH was defined by SAH on CT or an abnormal cerebrospinal fluid result in conjunction with positive results on cerebral angiography. A follow‐up period of 6 months was chosen. Results A total of 4407 patients met inclusion criteria; 397 (9%) patients were diagnosed with SAH on CT. A total of 388 patients underwent LP and 778 were admitted to hospital for further investigations and management. A total of 2613 patients discharged from ED without LP remained well at 6 months from their initial presentation, but 230 cases were lost to follow up. One patient died from haemorrhagic stroke during his third hospitalisation. A single patient demonstrated a true positive LP after a normal CT brain. Conclusion LP is not required in all patients with suspected SAH who have a negative CT scan. There are defining patient characteristics that can be used to risk stratify patients and may eliminate the need for LP.