Diffuse axonal injury is primarily characterized by what pathology?

Diffuse axonal injury is primarily characterized by what pathology?

• A. Microscopic tears of nerve fibers due to acceleration/deceleration
• B. Large focal contusion
• C. Subarachnoid hemorrhage due to aneurysm
• D. Demyelination of peripheral nerves

Answer: (A)

Diffuse axonal injury is defined by widespread microscopic tearing and shearing of axons caused by rapid acceleration–deceleration forces, especially rotational movement that pulls axons apart at the gray–white matter junction. This diffuse pattern contrasts with focal injuries, so instead of a single contusion, the injury spreads across many tracts, often producing profound neurologic impairment or coma. Microhemorrhages may be seen on sensitive MRI sequences, reflecting small axonal injuries, though a CT can appear normal early on. This mechanism is not about a localized brain bruise, a subarachnoid hemorrhage from an aneurysm, or demyelination of peripheral nerves, which involve different processes and locations.

Diffuse axonal injury is defined by widespread microscopic tearing and shearing of axons caused by rapid acceleration–deceleration forces, especially rotational movement that pulls axons apart at the gray–white matter junction. This diffuse pattern contrasts with focal injuries, so instead of a single contusion, the injury spreads across many tracts, often producing profound neurologic impairment or coma. Microhemorrhages may be seen on sensitive MRI sequences, reflecting small axonal injuries, though a CT can appear normal early on. This mechanism is not about a localized brain bruise, a subarachnoid hemorrhage from an aneurysm, or demyelination of peripheral nerves, which involve different processes and locations.