Abstract
Background: To ensure a good prognosis for subarachnoid hemorrhage (SAH), early diagnosis is essential. Although delayed diagnosis is associated with increased morbidity and mortality, it has been reported that 12% of cases of SAH are overlooked at initial assessment. Therefore, accurate prediction at the initial stage is necessary.
Objective: To identify objective predictive factors associated with SAH in patients admitted on an emergency basis with a chief complaint of a headache, and to propose a score for predicting the presence or absence of SAH by combining these factors.
Subjects and Methods: Among emergency patients brought by ambulance with a chief complaint of a headache during the nine-year period from 2001, a total of 573 patients were selected by excluding patients with trauma, drunkenness, or coma, as well as patients whose final outcome was unknown. Among these patients, those for whom data were obtained between January 1, 2001 and December 31, 2006 (356 cases) were used to derive a prediction rule and classified into the SAH group (n=88) and control (non-SAH) group (n=268) based on the diagnosis obtained on brain CT and lumbar puncture. Numerically expressed items such as vital signs and laboratory test values were investigated using univariate and multivariate logistic regression analyses in order to identify predictive factors, and an SAH prediction score (SPS) was created based on these factors. In addition, patient's data obtained between January 1, 2007 and December 31, 2009 (217 cases) were used to validate the SPS.
Results: In consideration of ease of use in clinical settings, the following factors and cutoff values were selected: white blood cell count >8,000/μl, blood glucose >130 mg/dl, serum potassium <3.5 mEq/l, systolic blood pressure >140 mmHg. By assigning points to these predictive factors, SPS was calculated for each group. No patients with an SPS of 0 had SAH. In addition, according to the derived prediction rule, the risk of SAH increased as SPS increased. Moreover, similar results were obtained for SPS in the validation.
Conclusion: The use of SPS may enable reliable prediction of SAH in initial assessment of patients with acute headache at emergency departments.
