Objective To determine the time course for the development of posttraumatic nonhemic subdural fluid collections in infants and young children.
Design Retrospective consecutive case series during 16 years.
Patients Fifty-five head trauma patients younger than 3 years with low attenuation subdural fluid on computed tomography.
Main Outcome Measure Time after head trauma when low attenuation fluid first becomes visible.
Setting Regional pediatric medical center.
Results The initial visualization of low attenuation subdural fluid was within 4 days of the trauma for 44 of the patients. The mean ± SD size of the subdural fluid collections when first identified was 4.6 ± 2.0 mm (range, 2-12 mm), and the maximum observed size was 7.7 ± 3.5 mm (range, 3-21 mm). The mean ± SD time after injury until the maximum observed size was 16 ± 18 days (range, 0-87 days). Low attenuation subdural fluid and high attenuation intracranial hemorrhage coexisted on at least 1 computed tomographic study during the first week after the trauma in 42 (81%) of the 52 patients with hemorrhage.
Conclusion Low attenuation subdural fluid collections (distinct from clotted blood) in infants and young children with head injuries most often develop during the first week after the traumatic event.
