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BMJ. 2015 Feb 18;350:h568. doi: 10.1136/bmj.h568.

Differentiation between traumatic tap and aneurysmal subarachnoid hemorrhage: prospective cohort study.

Author information

1
Department of Emergency Medicine, University of Ottawa, Ottawa Hospital Research Institute, Ottawa Hospital 1053 Carling Avenue Room F647, Ottawa, ON, Canada, K1Y 4E9 jperry@ohri.ca.
2
Department of Emergency Medicine, University of Ottawa, Ottawa Hospital Research Institute, Ottawa Hospital 1053 Carling Avenue Room F647, Ottawa, ON, Canada, K1Y 4E9.
3
University of Ottawa, Department of Emergency Medicine, Ottawa, ON, Canada.
4
Department of Emergency Medicine, University of Alberta, Edmonton, AB, Canada.
5
Hopital de l'Enfant-Jesus, Department of Emergency Medicine, Faculty of Medicine, Quebec City, QC, Canada G1J 1Z4.
6
Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
7
Department of Emergency Medicine, McMaster University, Hamilton, ON, Canada.
8
Department of Emergency Medicine, University of British Columbia, Vancouver, BC, Canada.
9
Division of Emergency Medicine, University of Toronto, Toronto, ON, Canada.
10
Division of Emergency Medicine, University of Western Ontario, London, ON, Canada.
11
Department of Emergency Medicine, University of Manitoba, Winnipeg, MB, Canada.
12
Division of Neurosurgery, University of Ottawa, Ottawa, ON, Canada.
13
Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa Hospital Research Institute, Ottawa, ON, Canada.

Abstract

OBJECTIVES:

To describe the findings in cerebrospinal fluid from patients with acute headache that could distinguish subarachnoid hemorrhage from the effects of a traumatic lumbar puncture.

DESIGN:

A substudy of a prospective multicenter cohort study.

SETTING:

12 Canadian academic emergency departments, from November 2000 to December 2009.

PARTICIPANTS:

Alert patients aged over 15 with an acute non-traumatic headache who underwent lumbar puncture to rule out subarachnoid hemorrhage.

MAIN OUTCOME MEASURE:

Aneurysmal subarachnoid hemorrhage requiring intervention or resulting in death.

RESULTS:

Of the 1739 patients enrolled, 641 (36.9%) had abnormal results on cerebrospinal fluid analysis with >1 × 10(6)/L red blood cells in the final tube of cerebrospinal fluid and/or xanthochromia in one or more tubes. There were 15 (0.9%) patients with aneurysmal subarachnoid hemorrhage based on abnormal results of a lumbar puncture. The presence of fewer than 2000 × 10(6)/L red blood cells in addition to no xanthochromia excluded the diagnosis of aneurysmal subarachnoid hemorrhage, with a sensitivity of 100% (95% confidence interval 74.7% to 100%) and specificity of 91.2% (88.6% to 93.3%).

CONCLUSION:

No xanthochromia and red blood cell count <2000 × 10(6)/L reasonably excludes the diagnosis of aneurysmal subarachnoid hemorrhage. Most patients with acute headache who meet this cut off will need no further investigations and aneurysmal subarachnoid hemorrhage can be excluded as a cause of their headache.

PMID:
25694274
PMCID:
PMC4353280
DOI:
10.1136/bmj.h568
[Indexed for MEDLINE]
Free PMC Article

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