Severe Diffuse Axonal Injury – Life Threatening Trauma

Severe Diffuse Axonal Injury Causes Most Severe Coma

By Gordon S. Johnson, Jr.

Severe Diffuse Axonal Injury is one of the worst of brain injuries. Yet severe diffuse axonal injury even may not appear on CT scans.

There is increasing recognition of the role of diffuse axonal injury in brain injury.  Yet most of the conversation around diffuse axonal injury is focused in context of milder brain injuries. In the context of severe brain injury, Severe Diffuse Axonal Injury (DAI) is brain injury which deal with immediate coma and terrible injury. The type of Severe Diffuse Axonal Injury (DAI) that initiates instant coma is called Type Three Diffuse Axonal Injury. In Severe Diffuse Axonal Injury, shear forces actually tear big parts of the brain’s axonal tracts.

Shear damage (what causes severe diffuse axonal injury) happens when brain layers of different weight and density slide across each other when the brain is rotated in an injury. In a severe diffuse axonal injury, the force literally severs the brain at its roots, the axonal tracts.

Axonal tracts are the groupings of axons which go from the gray matter into the white matter. The axonal tracts of myelinated neurons comprise the brain’s white matter. White matter axons are so called because they are covered with a white insulation, the myelin sheath.

One critically important axonal tract is the corpus callosum. The corpus callosum is the axonal tract which connects the brain’s right and left hemispheres. The corpus callosum is where the axonal tracts crisscross between the right and left sides of the brain.

Diffuse axonal injury is classified as Type One through Type Three. Type Three is the worst. Although Type Three diffuse axonal injury likely results in immediate unconsciousness and often death, it will not always display on a CT scan done on entry into the hospital. Most of brain injuries that involve immediate coma, involve severe diffuse axonal injury.