Validation of a severity score for the assessment of crotalid snakebite

Study objective: No research tool exists for the clinical evaluation of crotalid snakebite. We sought to determine the correlation of the snakebite severity score (SSS) with the clinical assessment of physicians experienced in the management of crotalid snakebite. Methods: We retrospectively used the SSS to quantify the severity of envenomation in 108 patients with crotalid snakebite. Two physicians experienced in the management of venomous snakebite independently and blindly assessed the severity of envenomation as detailed in medical records with the use of accepted clinical criteria. The correlation of the SSS and the physicians' consensus was determined with pointbiserial correlation. Results: The SSS correlated well with the physicians' consensus at presentation (r=+.63, z score=6.52, P<.000001) and at the point at which the patient's condition was worst (r=-t.70, z score=7.24, P<.000001). The SSS also correlated highly with the physicians' assessment of change in the patient's condition (r=+.51, z score=6.10, P<.000001). With the physicians' consensus as the gold standard, the sensitivity of a change in the SSS of 1 point in detecting clinically significant worsening of the envenomation syndrome was .97; specificity was .81. Conclusion: The SSS correlated well with the clinical condition of patients bitten by crotalid snakes as represented by the medical record. It provides a more objective instrument for the evaluation of severity and progression of envenomation in patients with crotalid snakebite.