[Diffuse axonal injury in traumatic brain injury]

Head trauma of varying severity may induce diffuse axonal injury. More attention is now given to this important type of injury, as examinations of head-injured patients with MRI have given us more knowledge.

We present a review of diffuse axonal injury with the main focus on clinical presentation and radiology, based on a Pubmed search and own experience.

Axons seldom rupture at the moment of injury. It is more common that it takes hours or a few days until the axons are detached. Areas most commonly affected are white matter in the hemispheres, corpus callosum and the brain stem. Half of the patients with severe head injury have diffuse axonal injury, but this type of injury also occurs in patients with moderate and mild head injury. The clinical presentation and prognosis will therefore vary. Diffuse axonal injury can present with typical signs revealed by CT, but the CT scan may also be normal, especially when there is no bleeding. New MRI techniques are more sensitive and show that diffuse axonal injury occurs more often than previously assumed. MRI is therefore necessary to give the patients correct diagnoses and adequate rehabilitation and follow-up.