Which statement describes diffuse axonal injury?

Which statement describes diffuse axonal injury?

• A. Diffuse axonal injury: disruption and tearing of axons and blood vessels from angular acceleration
• B. Local contusions and hematomas at the site of impact only
• C. Coup-countercoup injuries are the only form
• D. Fractures alone account for most damage

Answer: (A)

Diffuse axonal injury arises from rapid rotational forces that shear axons and small blood vessels across many white matter tracts, causing widespread axonal disruption rather than a single focal lesion. The statement reflects this mechanism: axons and nearby microvasculature are torn by angular acceleration, leading to diffuse brain injury. Clinically, this often presents with immediate or prolonged unconsciousness, and imaging can show microhemorrhages in regions like the corpus callosum and brainstem even when there isn’t a large focal bleed on initial scans. Local contusions and hematomas at the impact site describe a focal injury pattern, coup-contrecoup injuries are often focal or transient in nature, and fractures alone do not account for the diffuse axonal damage seen in DAI.

Diffuse axonal injury arises from rapid rotational forces that shear axons and small blood vessels across many white matter tracts, causing widespread axonal disruption rather than a single focal lesion. The statement reflects this mechanism: axons and nearby microvasculature are torn by angular acceleration, leading to diffuse brain injury. Clinically, this often presents with immediate or prolonged unconsciousness, and imaging can show microhemorrhages in regions like the corpus callosum and brainstem even when there isn’t a large focal bleed on initial scans. Local contusions and hematomas at the impact site describe a focal injury pattern, coup-contrecoup injuries are often focal or transient in nature, and fractures alone do not account for the diffuse axonal damage seen in DAI.