Bruising characteristics discriminating physical child abuse from accidental trauma.

OBJECTIVE Our objective was to conduct a pilot study to identify discriminating bruising characteristics and to model those findings into a decision tool for screening children at high risk for abuse. METHODS A case-control study of children 0 to 48 months of age who were admitted to a PICU because of trauma was performed. Case subjects (N = 42) were victims of physical abuse, and control subjects (N = 53) were children admitted because of accidental trauma during the same time period. Bruising characteristics (total number and body region) and patient age were compared for children with abusive versus accidental trauma. The development of a decision rule for predicting abusive trauma was accomplished with the fitting of a classification and regression tree through binary recursive partitioning. RESULTS Ninety-five patients were studied. Seventy-one (33 of 42 patients in the abuse group and 38 of 53 in the accident group) were found to have bruising, and the characteristics were modeled. Characteristics predictive of abuse were bruising on the torso, ear, or neck for a child <or=4 years of age and bruising in any region for an infant <4 months of age. A bruising clinical decision rule was derived, with a sensitivity of 97% and a specificity of 84% for predicting abuse. CONCLUSIONS Discriminating differences exist in bruising characteristics for abusive versus accidental trauma. The body region- and age-based bruising clinical decision rule model functions as a clinically sensible screening tool to identify young children who require further evaluation for abuse.