For a problem as pervasive as traumatic brain injury, one would think that the different forms it may take will be widely known and understood. Nevertheless, in my practice of community-based neurology, I find this isn’t the case. Patients and their families are rarely familiar with the concepts of cerebral contusion and concussion, and a common error is to believe that they’re essentially the same, except that a contusion is a more severe form of a concussion. Before exploring the differences between both of these terms, let us first acknowledge how they’re alike
The differences in between cerebral contusion and concussions
Both are due to head trauma. Both are common. Both are serious. But that is where the similarities end. The differences in between cerebral bruises and concussions can be boiled down to two basic concepts: Contusions are localized, while concussions are widespread. Contusions are macroscopic, while concussions are microscopic. To flesh out these concepts more fully we will need to discuss brain anatomy, brain physiology, and brain imaging technologies. A contusion is a bruise. At one time or another everybody has bruised himself or herself, as, for instance, when they hit a forearm against a hard object. This caused bleeding inside or beneath the skin. At the days after the injury, it turned purple and perhaps a wide range of other colors as the body’s repair mechanisms degraded and absorbed the red blood cells that had escaped from the injured blood vessels.
With the help of imaging technology, you can make your bruises visible.
The same thing can happen to the brain, except that the bruises aren’t located in a place the eye can see. Nevertheless, with the aid of imaging technology, the bruises can be made visible. To a close approximation, computed tomographic scans and magnetic resonance scans can see a level of detail corresponding to what the naked eye can see, except that the info is presented like slices of a loaf of bread, shown one slice at a time. Macroscopic implies that the naked eye can see the contusions. If a comparable process occurs at a microscopic level, it’s too small for the eye to see.
CT scan is more useful than MR scan
CT scans are more useful than MR scans in assessing patients with acute brain trauma because severely ill patients can be better monitored while receiving CT scans and since fresh hemorrhages are more apparent. In images created by CT scanners fresh blood appears intensely white, while normal brain tissue appears gray. Even though contusions can be multiple, they occur in single locations. That is what localized implies. So a brain contusion is both macroscopic and localized. One common pattern of contusions is coup contrecoup. When a moving head has abruptly stopped the brain nearest the point of impact bashes against the interior surface of the hard skull, producing a contusion.