Context Mortality and morbidity can be reduced if aneurysmal subarachnoid hemorrhage
(SAH) is treated urgently.
Objective To determine the association of initial misdiagnosis and outcome after
Design, Setting, and Participants Inception cohort of 482 SAH patients admitted to a tertiary care urban
hospital between August 1996 and August 2001.
Main Outcome Measures Misdiagnosis was defined as failure to correctly diagnose SAH at a patient's
initial contact with a medical professional. Functional outcome was assessed
at 3 and 12 months with the modified Rankin Scale; quality of life (QOL),
with the Sickness Impact Profile.
Results Fifty-six patients (12%) were initially misdiagnosed, including 42 of
221 (19%) of those with normal mental status at first contact. Migraine or
tension headache (36%) was the most common incorrect diagnosis, and failure
to obtain a computed tomography (CT) scan was the most common diagnostic error
(73%). Neurologic complications occurred in 22 patients (39%) before they
were correctly diagnosed, including 12 patients (21%) who experienced rebleeding.
Normal mental status, small SAH volume, and right-sided aneurysm location
were independently associated with misdiagnosis. Among patients with normal
mental status at first contact, misdiagnosis was associated with worse QOL
at 3 months and an increased risk of death or severe disability at 12 months.
Conclusions In this study, misdiagnosis of SAH occurred in 12% of patients and was
associated with a smaller hemorrhage and normal mental status. Among individuals
who initially present in good condition, misdiagnosis is associated with increased
mortality and morbidity. A low threshold for CT scanning of patients with
mild symptoms that are suggestive of SAH may reduce the frequency of misdiagnosis.