Brain Injuries

Today I would like to speak about brain injuries and a specific type of brain injury that is not uncommon: a diffuse axonal injury, often referred to as a shear injury. It is often seen in the car accident context and has been estimated to comprise about 50% of the traumatic brain injury hospitalizations. It is potentially very serious. It occurs from so-called acceleration/de-acceleration forces in the brain as the gelatin-like composition of the brain strikes the bony ridges of the skull.

The diffuse axonal injury (often abbreviated to DAI) results in shearing, tearing or rupturing of the axons that connect neurons in the brain. The nerve cells in the brain are composed of, among other things, neurons and axons, and axons send the messages from neuron to neuron. They are pathways. Medical science now is very sophisticated and with a susceptibility weighted MRI image, a certain kind of sophisticated MRI, you can see various abnormalities, including something known as hemosiderin deposition. These will show up years later and they are significant in the proof process. Hemosiderin deposition means staining from where there had been blood that has now dried. The staining will always remain. The hemosiderin deposition is a very concrete and clear way to prove the existence of a DAI or shear injury.

You may see in the official readings of the MRIs “multiple foci of hemosiderin”, really all over the brain. It is most often at what is known as the gray-white junction. The key thing to keep in mind with the shear injury, as with most brain injuries and indeed with most injuries, is that an MRI, if abnormal, will show you clear and objective evidence of the injury. Again, on MRI imaging, the diagnosis of shear injury is made by the findings of the radiologist of presence of hemosiderin deposition.

We can talk about the significance of a DAI and how that will manifest itself in the clinical sense. That would be a good topic for another blog but in this blog I want to emphasize that this type of a brain injury can be proven objectively. That means that the insurance company or defense attorney will have a hard time, if not an impossible time, to deny the existence of this serious brain injury.

There is ample literature for an attorney, or layperson, to review on shear injuries. As I have repeatedly said, there is no substitute for the lawyer being as acquainted with the injury and its effects as is possible. Because a shear injury will almost never appear on a CT Scan and may, though not necessarily, appear on an MRI, you may have to get yet another test to prove it. In those instances, you will not find evidence of the hemosiderin deposition that I have just spoken about. The point to remember is that certain other tests that may definitively show a shear injury are not tests that are on the front lines. Getting them could take some doing and/or arranging.

Shear injury is graded as are fractures. The location will affect the grade. For example, a shear injury in the corpus callosum, the mid-brain, is considered a Grade 3 shear injury, the worst of the rated categories.

Generally, I have dealt with very significant head injuries so they have been found on MRIs and even on the unsophisticated CT Scans. I have been told, and the literature confirms, that 95% of shear injuries do not show up on a CT Scan. When they do, they are usually quite severe because the CT Scan tends to miss additional areas of shear. In summation, diffuse axonal injury is usually more severe than is realized. In many cases, it will be predominately microscopic and therefore not well visualized. When it is, you are in the realm of a severe brain injury.