Validation of a Clinical Score to Predict Skull Fracture in Head-Injured Infants

Abstract

To validate a previously derived clinical score that uses clinical signs to determine which head-injured infants are at risk of skull fracture. The clinical score is calculated on the basis of the patient's age, the scalp hematoma size, and the location of the hematoma, with a total value between 0 and 8. We performed a prospective observational study of children younger than 2 years with blunt head trauma presenting to an urban pediatric emergency department. Among subjects who had head imaging performed (validation set), we assessed the utility of our clinical score to detect skull fracture and intracranial injury. In the 203 patients with imaging, 51 (25%) were diagnosed with skull fracture and 29 (14%) with intracranial injury. A clinical score of 4 or greater identified 90% (46/51) of patients with skull fracture with a sensitivity of 0.90 (95% confidence interval [CI], 0.78-0.96) and a specificity of 0.78 (95% CI, 0.70-0.84). A clinical score of 3 or greater identified 93% (27/29) of those with an intracranial injury with a sensitivity of 0.93 (95% CI, 0.76-0.99) and a specificity of 0.42 (95% CI, 0.35-0.50). A score of 3 or greater identified 100% of intracranial injury among asymptomatic patients. We have validated our clinical scoring system as an accurate way of determining an infant's risk of skull fracture. Whereas a clinical score of 4 or greater maximizes the trade-off between sensitivity and specificity for identifying skull fracture, a clinical score of 3 or greater may be preferable for detecting intracranial injury.