Neuroscience Clerkship at UH/VA
 

CEREBRAL CONCUSSION VS CONTUSION

 

The terms cerebral concussion and contusion are often inappropriately used as if they are interchangeable. They both may follow head injury, but are very different in their meaning and prognosis for the patient.

 

Concussion

Contusion

Definition

 Immediate but transient loss of consciousness, associated with short period of amnesia.

 Surface bruise of brain with varying degrees of petechial hemorrhage, edema, and tissue destruction.

Mechanism of Injury

Transient electrophysiological dysfunction of reticular activating system due to rotation of cerebral hemispheres around a fixed brainstem.

Deceleration of brain against the skull.  Coup lesion occurs at point of brain impact, contre-coup lesion occurs when brain swings back.

Clinical Signs

Most patients are neurologically normal, although brief convulsion, facial pallor, bradycardia, faintness and  sluggish pupillary reaction may occur.

Memory loss is usually limited to brief period of time surrounding the injury; occasionally, weeks of memory loss may occur.

Permanent neurological deficit following concussion does not occur.

Focal neurologic signs (e.g., hemiparesis, gaze preference, etc.) and/or altered mental state. In severe lesions, coma and extensor posturing. 

Edema often follows as a secondary effect and may put the patient at risk of herniation.

Imaging CT and MRI usually normal.

CT: areas of contusion are often inhomogeneous hyperdensities (i.e., blood) with surrounding edema and mass effect.

MRI: petechtial blood or frank contusion (MRI appearance depends on sequence and timing). MRI may also be able to visualize diffuse axonal shearing injury a few days later.

 

Example Imaging