Diffuse Axonal Injury

In a patient with depressed consciousness after head trauma, obtain noncontrast head CT urgently to identify lesions requiring neurosurgical action, including focal hemorrhage, contusion, or mass effect. A relatively normal CT does not exclude diffuse axonal or vascular injury, particularly when coma or examination severity is disproportionate to visible structural injury. BMJBMJConcussion is confusing us all | Practical Neurology

Treat diffuse injury in the severe TBI pathway when the patient has a positive head CT with elevated ICP or has a Glasgow Coma Scale score below 8 and is not following commands in the setting described for ICP monitoring. Diffuse injury does not preclude a concurrent focal lesion; a focal surgical lesion changes the management priority toward neurosurgical intervention rather than attributing the examination solely to axonal injury. Wolters KluwerWolters KluwerTrauma : Operative Neurosurgery

Avoid secondary brain injury while serially reassessing pupils, motor examination, sedation exposure, and CT evolution. Diffuse traumatic injury may coexist with subarachnoid hemorrhage, cerebral edema, hypoxia, hypotension, and intracranial hypertension; each is a potentially modifiable contributor to neurological deterioration. Wolters KluwerWolters KluwerTraumatic Brain Injury - Continuum

Order brain MRI for persistent unexplained coma, prolonged post-traumatic disorder of consciousness, or disabling cognitive deficits when CT does not account for the clinical state. Conventional CT and MRI can miss diffuse axonal and vascular injury; therefore, a negative structural study should not be used to reassure clinicians that axonal injury is absent. BMJBMJConcussion is confusing us all | Practical Neurology

Include susceptibility-sensitive imaging, preferably susceptibility-weighted imaging, because it is more sensitive than T2-weighted gradient-echo imaging for traumatic hemorrhagic lesions. Microbleeds visualized on gradient-echo or susceptibility-weighted imaging are a stable marker of white-matter injury after TBI. JAMA+1JAMADiffusion Tensor Tractography of Traumatic Diffuse Axonal ...BMJConcussion is confusing us all | Practical Neurology

Include diffusion-sensitive MRI when available to assess white-matter microstructural injury. Diffusion tensor imaging quantifies water diffusion properties in white-matter tracts and can detect changes associated with axonal injury, but its clinical availability and individual-level diagnostic role remain less established than routine structural and susceptibility-sensitive MRI. BMJ+1BMJConcussion is confusing us all | Practical NeurologyBMJDiffusion tensor imaging studies of mild traumatic brain injury: a meta-analysis | Journal of Neurology, Neurosurgery & Psychiatry

For patients with monitored intracranial hypertension, use ICP greater than 22 mm Hg as a treatment threshold. Initial measures include head elevation plus adequate analgesia and sedation; assess the contemporaneous CT for a new mass lesion and correct systemic contributors to cerebral injury before labeling ICP elevation as refractory diffuse injury. Wolters Kluwer+1Wolters KluwerTrauma : Operative NeurosurgeryWolters KluwerTraumatic Brain Injury - Continuum

Do not give steroids for diffuse axonal injury or other TBI to reduce ICP or improve neurological outcome. Avoid prophylactic hyperventilation because excessive hypocapnia can lead to further brain hypoxia; any use of ventilation manipulation should be individualized to an acute ICP emergency rather than routine management. Wolters KluwerWolters KluwerTrauma : Operative Neurosurgery

Post-traumatic antiseizure medication can reduce early post-traumatic seizures during the first 7 days after injury but has not been shown to prevent post-traumatic epilepsy. Use this distinction when discussing the goal and duration of seizure prophylaxis in severe TBI. Wolters KluwerWolters KluwerTrauma : Operative Neurosurgery

Decompressive procedures are not a reflex response to MRI-defined diffuse injury. Consider surgical escalation in the setting of refractory ICP after medical management and imaging reassessment, recognizing that hemicraniectomy has reported complication risk of 30% to 40%. Wolters KluwerWolters KluwerTrauma : Operative Neurosurgery

MRI findings compatible with isolated diffuse axonal injury are associated with persistent cognitive impairment. Use this association to trigger early cognitive and rehabilitation planning, while avoiding a lesion-only prediction of long-term function. JAMAJAMACognitive Sequelae of Diffuse Axonal Injury

Diffuse axonal injury has greater prognostic uncertainty than isolated intracranial hemorrhage in practice patterns surrounding withdrawal of life-sustaining treatment. This uncertainty should prompt serial examinations, review of confounders such as sedation and systemic injury, and multidisciplinary communication before irreversible decisions. BMJBMJPatterns in withdrawal of life-sustaining treatment in trauma ...

When a patient remains behaviorally unresponsive, distinguish unresponsive wakefulness syndrome from potentially covert awareness through structured consciousness assessment. Specialized testing, including functional MRI, has identified covert awareness in some behaviorally unresponsive patients; this possibility reinforces the need for repeated assessment rather than a single early examination. BMJBMJEvaluation of coma - Differential diagnosis of symptoms | BMJ Best Practice US

Persistent impairment after traumatic axonal injury is not limited to motor outcome. White-matter network disruption is implicated in cognitive dysfunction, and microbleed burden has been associated with cognitive impairment in MRI-defined isolated diffuse axonal injury. BMJ+1BMJthe BIO-AX-TBI study protocolJAMACognitive Sequelae of Diffuse Axonal Injury

For patients who emerge from coma or survive with persistent deficits, arrange rehabilitation assessment focused on cognitive impairment, functional dependence, and disorders of consciousness. MRI-defined isolated diffuse axonal injury is associated with persistent cognitive impairment, making cognitive follow-up a necessary component of discharge planning rather than an optional referral. JAMA+1JAMACognitive Sequelae of Diffuse Axonal InjuryBMJHead injury | Practical Neurology

In patients with mild TBI and persistent symptoms despite normal routine imaging, avoid dismissing symptoms solely because CT or conventional MRI is unrevealing. Advanced susceptibility and diffusion MRI can identify diffuse injury more sensitively, but DTI abnormalities in mild TBI are inconsistent across studies and should not be used as a solitary diagnostic biomarker. BMJ+1BMJConcussion is confusing us all | Practical NeurologyBMJDiffusion tensor imaging studies of mild traumatic brain injury: a meta-analysis | Journal of Neurology, Neurosurgery & Psychiatry

Document seizure prophylaxis stop dates when used for early post-traumatic seizure prevention. Continuing an antiseizure agent beyond the early prophylaxis objective should be based on an actual seizure disorder or another individualized indication, because early prophylaxis has not been shown to prevent post-traumatic epilepsy. Wolters KluwerWolters KluwerTrauma : Operative Neurosurgery