The paper by Dunning et al¹ in this issue discusses a classic medical screening problem. Particularly during the long, light summer evenings, every accident and emergency department in the country sees large numbers of children who have sustained traumatic head injuries, most of which seem trivial; but among such children, there are a small number who are at avoidable risk of severe disability or death. How can they be identified most effectively? In the reported series of around 20 000 children, 95% had not even a brief loss of consciousness and 97% had a Glasgow Coma Scale of 15, but at the tip of the severity pyramid were 281 (1.2%) children with abnormal computed tomograms, 137 (0.6%) of whom required a neurosurgical procedure, and 15 deaths (although the paper does comment on how many of these deaths were deemed potentially preventable).

The authors point out the weakness of the evidence base (and thus the current National Institute of Clinical Evidence guidelines) in this area, particularly in relation to children, and are to be commended for the largest prospective paediatric study of this problem to date. Their paper derives a clinical decision rule that identifies high-risk children warranting computed tomography, and they have deliberately prioritised sensitivity over specificity.

The traditional approach to this problem (which might be described as “observation-first”) relied on a combination of skull x rays …