Low plasma D-dimer predicts absence of intracranial injury and skull fracture.

Abstract

Intracranial injury (ICI) is a leading cause of morbidity in children; however, the use of computed tomography (CT) to evaluate ICI has significant risks in children. A recent study suggests D-dimer is associated with ICI. We surveyed the performance of plasma D-dimer in ruling out ICI or skull fracture (SF) in children with head trauma. In a cross-sectional study in the Emergency Department (ED) at the National Center for Child Health and Development in Tokyo, Japan we reviewed the medical records of all children age 0-16years brought to the ED with head trauma from January 2010 to July 2013, who underwent CT based on established clinical criteria and had plasma D-dimer measured. We evaluated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of plasma D-dimer, using abnormal findings on CT (ICI, SF) as the criterion standard. We repeated analysis after stratification by age (<2years, ≥2years). Among 364 eligible children (112 children <2year of age), abnormal findings on CT were demonstrated in 33.8% (123/364). With the cut-off set at 0.5μg/mL, sensitivity was 100.0% (95% confidence interval [CI]: 95.6-100.0%), specificity 34.0% (95%CI: 28.1-40.4%), PPV 43.6% (95%CI: 37.7-49.6%), NPV 100.0% (95%CI: 93.5-100%). After stratification by age (<2years and ≥2years), sensitivity (100.0% and 100.0%) and NPV (100.0% and 100.0%) remained high in both age groups. Low plasma D-dimer (≤0.5μg/mL) is useful to limit the use of CT in children by excluding traumatic ICI or SF.