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Management of sudden onset severe headache patients presenting to the emergency Department: systematic review of diagnostic accuracy studies

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Publication details

JournalEmergency Medicine Journal
DateAccepted/In press - 14 Mar 2022
DateE-pub ahead of print (current) - 31 Mar 2022
Number of pages8
Early online date31/03/22
Original languageEnglish


Objective Advances in imaging technologies have precipitated uncertainty and inconsistency in the management of neurologically intact patients presenting to the Emergency Department with non-traumatic sudden onset severe headache with a clinical suspicion of subarachnoid haemorrhage (SAH). The objective of this systematic review was to evaluate diagnostic strategies in these patients.

Methods Studies assessing any decision rule or diagnostic test for evaluating neurologically intact adults with a severe headache, reaching maximum intensity within one hour, were eligible. Eighteen databases (including MEDLINE and Embase) were searched. Quality was assessed using QUADAS-2. Where appropriate, hierarchical bivariate meta-analysis was used to synthesise diagnostic accuracy results.

Results Thirty-seven studies were included. Eight studies assessing the Ottawa SAH clinical decision rule were pooled; sensitivity 99.5% (95% confidence interval [CI] 90.8-100), specificity 24% (95% CI 15.5-34.4). Four studies assessing computed tomography (CT) within six hours of headache onset were pooled; sensitivity 98.7% (95% CI 96.5-100), specificity 100% (95% CI 99.7-100). The sensitivity of CT beyond six hours was considerably lower (≤90%; 2 studies). Three studies assessing lumbar puncture (LP; spectrophotometric analysis) following negative CT were pooled; sensitivity 100% (95% CI 100-100), specificity 95% (95% CI 86.0-98.5).

Conclusion The Ottawa SAH Rule rules out further investigation in only a small proportion of patients. CT undertaken within six hours (with expertise of a neuroradiologist or radiologist who routinely interprets brain images) is highly accurate and likely to be sufficient to rule out SAH; CT beyond six hours is much less sensitive. The CT – LP pathway is highly sensitive for detecting SAH and some alternative diagnoses, although LP results in some false positive results.

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© Author(s) (or their employer(s)) 2022

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