Published Online
on February 22, 2007

A more recent version of this article appeared on April 1, 2007

This Article Full Text (PDF) CME: Take the course for this article: Stroke: April 2007, Volume 38, Number 4 All Versions of this Article: 38/4/1216    most recent 01.STR.0000259661.05525.9av1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Vermeulen, M. J. Articles by Schull, M. J. Search for Related Content PubMed PubMed Citation Articles by Vermeulen, M. J. Articles by Schull, M. J. Related Collections Health policy and outcome research CT and MRI Cerebral Aneurysm, AVM, & Subarachnoid hemorrhage Related Article

Submitted on September 8, 2006
Revised on October 16, 2006
Accepted on November 15, 2006

Missed Diagnosis of Subarachnoid Hemorrhage in the Emergency Department

Marian J. Vermeulen MHSc and Michael J. Schull MD, MSc, FRCPC^*

From the Institute for Clinical Evaluative Sciences (M.J.V., M.J.S.), Toronto, Canada; the Clinical Epidemiology Unit and the Department of Emergency Services (M.J.S.), Sunnybrook Health Sciences Centre, Toronto; the Department of Medicine (M.J.S.), University of Toronto; and the Department of Health Policy, Management and Evaluation (M.J.V., M.J.S.), University of Toronto.

^* To whom correspondence should be addressed. E-mail: mjs{at}ices.on.ca.

Background and Purpose--Subarachnoid hemorrhage (SAH) can be devastating, yet its initial presentation may be limited to common symptoms and subtle signs, potentially leading to misdiagnosis. Little is known about population rates of misdiagnosis of SAH, or hospital factors that may contribute to it. We estimated the population-based rate of missed SAH among emergency department (ED) patients and examined its relationship with hospital characteristics.

Methods--We studied persons admitted with a nontraumatic SAH to all Ontario hospitals over 3 years (April 2002 to March 2005). SAH was defined as missed if the patient had an ED visit related to the SAH (based on a prespecified definition) in the 14 days before admission. We examined the association between hospital teaching status and missed SAH and explored whether annual ED volume of SAH or CT availability explained this association.

Results--Of 1507 patients diagnosed with SAH, 5.4% (95% CI, 4.3 to 6.6) had a missed diagnosis. The risk was significantly higher among patients triaged as low acuity (odds ratio 2.65; 95% CI, 1.46 to 4.80), as well as in nonteaching hospitals (adjusted odds ratio 2.12; 95% CI, 1.02, 4.44). Neither ED SAH volume nor on-site CT availability explained the effect of teaching status.

Conclusions--About 1 in 20 SAH patients are missed during an ED visit. Lower acuity patients are at higher risk of misdiagnosis, suggesting the need for heightened suspicion among patients with minimal clinical findings. The risk is also greater in nonteaching hospitals, but this is not explained by the annual volume of SAHs seen in the ED or access to CT.

Key words: diagnosis • health services research • subarachnoid hemorrhage

Related Article:

Diagnosis of Subarachnoid Hemorrhage: Are We Doing Better?

Jonathan A. Edlow
Stroke 2007 38: 1129-1131. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

				A. R. SCHONFELD and M. A McMULLEN Treatment of Brain Aneurysms Radiol. Technol., July 1, 2008; 79(6): 515 - 531. [Abstract] [Full Text] [PDF]

				D.P. Breen, C.W. Duncan, A.E. Pope, A.J. Gray, and R. Al-Shahi Salman Emergency department evaluation of sudden, severe headache QJM, June 1, 2008; 101(6): 435 - 443. [Abstract] [Full Text] [PDF]

				J. A. Edlow, R. E. Rothman, and W. G. Barsan What Do We Really Know About Neurological Misdiagnosis in the Emergency Department? Mayo Clin. Proc., February 1, 2008; 83(2): 253 - 254. [Full Text] [PDF]

				J. A. Edlow Diagnosis of Subarachnoid Hemorrhage: Are We Doing Better? Stroke, April 1, 2007; 38(4): 1129 - 1131. [Full Text] [PDF]