Objective: To determine the frequency with which a CT head is performed in patients presenting more than 4 h after minor head injury and the clinical features that predict an abnormal scan.
Design: Observational cohort study.
Setting: Emergency department (ED) of the Royal London Hospital, London, UK.
Participants: 500 patients presenting to the ED of the Royal London Hospital.
Methods: Chart review of all patients with minor head injury presenting more than 4 h from insult to the ED between December 2007 and May 2009. Inclusion criteria were: age over 16 years, Glasgow coma scale (GCS) 14 or 15 on first assessment, over 4 h post-injury. Exclusion criteria were: age under 16 years, GCS 13 and less, injuries limited to the face with no risk of intracranial injury; presentation less than 4 h after injury.
Results: 497 patients were identified: 147 patients had CT head; 11 had intracranial injuries on CT. Loss of consciousness (p=0.0005), potential coagulopathy (p=0.0015), injuries above the clavicles (p=0.0150), open/depressed skull fracture (p=0.0221), alcohol/drug intoxication (p=0.0406) and focal neurology (p=0.0562) were predictors of positive CT scan. Five patients (1% of sample, 45% of patients with abnormal CT) required a neurosurgical procedure. Two (18.2%) self-discharged and four (36.4%) were followed up as outpatients. One patient (0.09%) died as a result of intracranial injury.
Discussion: Patients with minor head injury who present over 4 h post-insult exhibit a similar risk of intracranial pathology to those presenting within 4 h. The risk factors previously identified to predict intracranial injury are similar in this study.