Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan.
The emergency management of cerebral concussion typically centers on the decision to perform a head computed tomography (CT) scan, which only rarely detects hemorrhagic lesions requiring neurosurgery. The absence of hemorrhage on CT scan often is equated with a lack of brain injury. However, observational studies revealing poor long-term cognitive outcome after concussion suggest that brain injury may be present despite a normal CT scan. To explore this idea further, the authors reviewed the evidence for objective neurologic injury in humans after concussion, with particular emphasis on those with a normal brain CT. This evidence comes from studies involving brain tissue pathology, CT scanning, magnetic resonance image (MRI) scanning, serum biomarkers, formal cognitive and balance tests, functional MRI, positron emission tomography, and single-photon emission computed tomography scanning. Each section is accompanied by technical information to help the reader understand what these tests are, not to endorse their use clinically. The authors discuss the strengths and weaknesses of the evidence in each case. These reports make a compelling case for the existence of concussion as a clinically relevant disease with demonstrable neurologic pathology. Areas for future emergency medicine research are suggested.
Bazarian
Jeffrey J
JJ
Department of Emergency Medicine, Strong Memorial Hospital, University of Rochester, Rochester, NY 14642, USA. jeff_bazarian@urmc.rochester.edu
Blyth
Brian
B
Cimpello
Lynn
L
D001369:Axons / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D001924:Brain Concussion / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D001930:Brain Injuries / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D020833:Diffuse Axonal Injury / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D009414:Nerve Growth Factors / Q000097:blood; D049268:Positron-Emission Tomography; D004856:Postural Balance; D011237:Predictive Value of Tests; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D015415:Biomarkers; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins