Rate of Intracranial Hemorrhage After Minor Head Injury

Computed tomography scans of the head (CTH) are an important component of the initial patient evaluation after blunt head trauma in select patients. Here we review findings of CTH performed for mild traumatic brain injury (TBI) at a Level I trauma center over a two-year period. We subsequently discuss the role and limitations of published clinical decision rules aiming to decrease unnecessary CTH in mild TBI patients.

We reviewed all Emergency Department CTH obtained after blunt head trauma between 2010 and 2011. Patient demographics and radiology report texts were collected. Reports were cross-referenced with our institutional trauma database to obtain initial Glasgow Coma Scale (GCS). Mild TBI was defined by an initial GCS 13-15 with or without loss of consciousness or post-traumatic amnesia.

There were 5,634 mild TBI patients evaluated with CTH. A total of 477 scans (8.5%) were positive for intracranial hemorrhage. Of these, 188 (39.4%) showed more than one type of intracranial hemorrhage. The most common findings were subdural hematomas (262, 4.7% of scans), traumatic subarachnoid hemorrhages (252, 4.5% of scans), and cerebral contusions/intraparenchymal hematomas (212, 3.8% of scans). Older age (p<0.001) and male gender (p<0.001) were associated with positive CTH.

The rate of positive CTH in mild TBI patients in our population falls within a historical range. The clinical and medicolegal implications of missed intracranial hemorrhage have remained important factors limiting the implementation of clinical decision rules in screening mild TBI patients for CTH.