Management of Diffuse Axonal Injury
Immediate Diagnostic Imaging
Non-contrast CT must be performed immediately without delay as the mandatory first-line imaging in all patients with suspected moderate to severe traumatic brain injury. 1, 2 This is critical despite CT's significant limitation—it detects only 10% of DAI cases because over 80% of axonal lesions lack macroscopic hemorrhage. 3
MRI is required when CT is normal but neurologic deficits persist unexplained. 1, 2 The optimal MRI protocol includes three specific sequences: T2*-weighted gradient-echo (GRE) imaging for microhemorrhages, susceptibility-weighted imaging (SWI) which is 3-6 times more sensitive than GRE, and diffusion-weighted imaging (DWI) to visualize non-hemorrhagic axonal injuries. 2, 4
For prognostication, early MRI (within acute phase) improves prediction of 3-month outcomes, particularly in mild TBI patients with normal CT—approximately 27% will show abnormalities on MRI. 3, 2
Acute Physiological Management
Blood Pressure Control
Maintain systolic blood pressure >110 mmHg continuously using vasopressors (phenylephrine or norepinephrine) when needed. 1, 4 This threshold ensures adequate cerebral perfusion and prevents secondary ischemic injury.
Ventilation Management
Perform tracheal intubation with mechanical ventilation and continuous end-tidal CO2 monitoring. 1, 4 Critically, avoid hypocapnia—it causes cerebral vasoconstriction and increases brain ischemia risk. 1, 4
Intracranial Pressure Monitoring
ICP monitoring is mandatory for severe TBI patients, with intervention threshold typically at ICP >20 mmHg. 1, 4 For persistent intracranial hypertension despite sedation and correction of secondary insults, proceed to external ventricular drainage. 4 Decompressive craniectomy may be considered for refractory cases. 4
Rehabilitation and Prevention of Complications
Initiate physical therapy immediately once the patient is stabilized to prevent joint contractures and muscle atrophy. 1, 4 Specific interventions include:
- Proper positioning with frequent repositioning to prevent pressure sores 1, 4
- Range of motion exercises started as soon as stabilized 4
- Splinting to maintain joint alignment and prevent contracture formation 4
Monitoring Strategy
Perform regular neurological assessments to detect deterioration, but reserve follow-up imaging for clinical deterioration rather than routine scheduling. 1, 4 This avoids unnecessary radiation while capturing clinically significant changes.
Prognostic Indicators
The location and extent of DAI lesions directly correlate with outcomes. 2, 4 DAI Stage 3 (dorsolateral brainstem lesions) predicts poor outcomes. 2 The presence of both a contusion and >4 foci of hemorrhagic axonal injury on MRI independently predicts worse prognosis. 2, 4
Multidisciplinary Coordination
Conduct regular multidisciplinary case reviews for all severe DAI patients and establish early communication with regional neuroscience centers. 1, 4 Initiate honest discussions about likely outcomes at admission and establish patient values early to guide potential end-of-life care planning. 1
Critical Pitfalls to Avoid
DAI is commonly underdiagnosed with conventional CT—do not rely on negative CT to exclude DAI in patients with immediate coma from trauma. 4, 5 The number of microhemorrhages, while diagnostically helpful, does not correlate with injury severity or outcomes. 2, 4 Gadolinium contrast is unnecessary for conventional MRI in TBI. 2
The pathophysiology involves rapid axonal stretch damaging the cytoskeleton, causing calcium entry, protease activation, and eventual axonal disconnection—there is no specific treatment for this primary damage, making prevention of secondary injury paramount. 2, 5