Determining the diagnostic utility of lumbar punctures in CT negative suspected subarachnoid hemorrhage: A Systematic Review and Meta-analysis.

Abstract INTRODUCTION While headache is a common neurological symptom, subarachnoid hemorrhage (SAH) is a rare and potentially catastrophic cause of sudden onset severe headache. The utility of the imaging modalities and interventional procedures are central to the investigation of the causes of headache; however, are not without their limitations, risks and complications. METHOD A meta-analysis in accordance to the Preferred Reporting for Systematic Reviews and Meta-analysis (PRISMA) guidelines was conducted searching PubMED, EMBASE and Google Scholar. Patients investigated for suspected subarachnoid hemorrhage (SAH) with a computed tomography (CT) negative CT and positive lumbar puncture (LP) and final diagnosis of SAH were included. The sensitivity of LP in the context of a negative CT and subsequent imaging confirming the cause of SAH (CTA, MRA, DSA) was quantified. The pooled data was analysed using the DerSimonian-Laid random effects model. RESULTS Four studies with 2782 patients who presented with headache suspicious for a SAH were included with an initial negative CT report and a subsequent LP to rule out SAH. All included studies were observational prospective cohort design. A combined pooled proportion of 0.383 (0.077, 0.756), 0.086 (0.007, 0.238) and 0.22 (0.04, 0.49) for LP+, DSA+ and DSA/CTA+ investigations were estimated with a 95% confidence interval. CONCLUSION The current clinical workflow of an LP after a negative CT head for a patient presenting with a sudden onset severe headache is observed to have a high enough proportion to warrant its continued use despite the sensitivity of modern CT scanners of > 97%.