Diffuse Brain Injury / Diffuse pathology
Diffuse brain injury, unlike other traumatic brain lesions, occurs without the head being touched by something or hit by something. It is caused by the fact that the brains are shaken. This causes damage to the connections between nerve cells. Also oxygen deficiency can give diffuse injury. The lesion is then wherever the brains were deprived of oxygen. This is called Diffuse Axonal Injury (DAI). This type of damage is often spread over a larger part of the brains than a focal (local) damage. Because a larger part of the brains is damaged, there may be more problems.
This diffusely scattered injury is often difficult to see on a scan. A CT scan will usually show no abnormalities. MRI images are more likely to show abnormalities. It often happens that there is diffuse brain injury, while neither CT nor MRI brain damage show brain injury. The severity of symptoms varies from very minor temporary damage to severe permanent disability or even a fatal outcome.
Explanation about the axon and consequences of damage
An axon is a long offshoot from a nerve cell that transmits the signal to another neuron, a muscle cell or a cell of a gland. In diffuse axonal injury in several places in the brains axons are stretched too far. Axons are thereby snapped or torn and thereby the brain signals can no longer be transmitted. The tearing of axons causes the release of chemicals (neurotransmitters). These neurotransmitters can cause surrounding cranial nerves to die. Therefore, the consequences after a few hours to a day after the accident may worsen.
When an MRI shows no damage
Many brain injury victims who have no visible consequences, have to deal with prejudices of their environment, even from doctors or insurance companies. They have survived the brain damage but do not receive support to meet life with its enormous constraints. Some skeptics refuse to believe that brain injury exists, unless there is strong medical evidence. Focal brain injury leaves scars which are clearly visible on MRI or CT scans.
However, by advances in functional imaging MRI centers are often able to recognize this injury. It is to be expected that in the future the possibilities to recognize this injury on MRI will be improved. For more information, see this website.
This injury can cause swelling. It is important to reduce this, because swelling can cause additional damage. Steroids or other medications designed to reduce inflammation and swelling are used.
Focal Brain Injury / Focal pathology
Focal injury, an injury at the location where the trauma occurred (coup) and / or at the place on the other side of the brains of the site of the trauma in the direction of the force of the trauma (contrecoup). This usually happens after a direct blow to the head, causing a skull fracture. There is often a bruise in the brains under the skull fracture. If the lesion is in one particular spot or two spots, an MRI or CT scan can often make it visible.
More information about diffuse and focal injury on the website of Braininjury Institute
Coup / contrecoup see video: