What is the appropriate management and treatment for a patient with diffuse axonal injury?

Management of Diffuse Axonal Injury

For patients with diffuse axonal injury, immediate non-contrast CT is mandatory for initial assessment, followed by MRI with specialized sequences (T2-weighted GRE, susceptibility-weighted imaging, and diffusion-weighted imaging) when CT is normal but neurologic findings persist, combined with aggressive physiological management targeting systolic blood pressure >110 mmHg, controlled ventilation to avoid hypocapnia, and ICP monitoring for severe cases.* 1, 2, 3

Diagnostic Approach

Initial Imaging

• Non-contrast CT is the mandatory first-line imaging in acute moderate to severe traumatic brain injury and must be performed without delay 1, 2, 3
• CT has significant limitations: it detects only 10% of DAI cases because most lesions lack macroscopic hemorrhage visible on conventional CT 1, 3
• CT can predict mortality and unfavorable outcomes despite its limited sensitivity for DAI 1

Advanced Imaging with MRI

• MRI is indicated when CT results are normal but persistent unexplained neurologic findings are present (Class I recommendation) 1, 2, 3
• MRI can detect DAI lesions within the first 24 hours after injury 1, 3
• Approximately 27% of mild TBI patients with normal CT show abnormalities on early MRI that improve prediction of 3-month outcomes 1, 3

Optimal MRI sequences for DAI detection:

• T2*-weighted gradient-echo (GRE) imaging: sensitive to microhemorrhages in acute, early subacute, and chronic stages 1, 3
• Susceptibility-weighted imaging (SWI): 3-6 times more sensitive than T2* GRE in detecting hemorrhagic axonal injuries 1, 3
• Diffusion-weighted imaging (DWI): visualizes axonal injuries not easily appreciated on other sequences 1, 3

Critical caveat: Gadolinium-based contrast agents are not necessary for conventional MRI in TBI 1

Acute Physiological Management

Blood Pressure Management

• Maintain systolic blood pressure >110 mmHg to ensure adequate cerebral perfusion 2, 3
• Avoid hypotension, which compounds secondary brain injury 3

Ventilation Control

• Control ventilation through tracheal intubation and mechanical ventilation with end-tidal CO2 monitoring 2, 3
• Prevent hypocapnia, which causes cerebral vasoconstriction and increases the risk of brain ischemia 2, 3

Intracranial Pressure Management

• ICP monitoring is recommended for patients with severe TBI to detect intracranial hypertension 2, 3
• Intervention threshold is typically ICP >20 mmHg 2, 3
• External ventricular drainage is suggested for treating persisting intracranial hypertension despite sedation and correction of secondary brain insults 3
• Decompressive craniectomy may be considered for refractory intracranial hypertension in multidisciplinary discussion 3

Prognostic Assessment

Imaging-Based Prognostic Factors

• DAI grading correlates strongly with outcomes: Grade III DAI (dorsolateral brain stem lesions) is associated with poor outcomes and highest mortality 1, 3
• The presence of both a contusion and >4 foci of hemorrhagic axonal injury on MRI is an independent prognostic predictor 1, 3
• The location and extent of DAI lesions correlate with clinical outcomes 1, 3

Important caveat: The number of microhemorrhages, while helpful for accurate diagnosis, is not currently thought to be associated with injury severity or outcomes 1, 3

Clinical Prognostic Factors

• Dysautonomia is associated with higher mortality (odds ratio 4.17) 4
• Hyperglycemia ≥8 mmol/L on ICU admission is associated with both higher mortality (odds ratio 3.84) and poor outcome (odds ratio 5.55) 4
• Glasgow Coma Scale score <8 is associated with poor outcome (odds ratio 3.55) 4
• DAI count ≥6 is associated with poor outcome (odds ratio 3.33) 4

Rehabilitation and Long-Term Management

Early Rehabilitation

• Early physical therapy and rehabilitation are essential to prevent joint contractures and muscle atrophy 2, 3
• Specific interventions include proper positioning, frequent repositioning, range of motion exercises, and splinting 2, 3
• Regular neurological assessments are necessary to detect clinical deterioration 2

Follow-Up Imaging

• Follow-up imaging is indicated with neurological deterioration rather than on a routine basis 2, 3
• Repeat non-contrast CT is recommended for patients with epidural, subdural, and parenchymal hematomas 3

Multidisciplinary Care Coordination

• Regular multidisciplinary case reviews are recommended for patients with severe DAI 1, 2, 3
• Early communication with regional neuroscience centers is essential for patients with perceived devastating brain injury 2, 3
• A period of physiological stabilization and observation is recommended for patients with perceived devastating injury to improve the quality of decision-making 3
• Establish patient values and preferences early to guide end-of-life care planning if needed 2
• For elderly patients with severe injuries unlikely to be fully recoverable, early insertion of palliative medicine consultation improves outcomes, reduces in-hospital mortality and length of stay, and improves communication with family 3

Common Pitfalls to Avoid

• Do not rely solely on CT for DAI diagnosis: More than 80% of DAI lesions lack macroscopic hemorrhage visible on CT 1
• Do not perform routine follow-up imaging: Only image when there is neurological deterioration 2, 3
• Do not use gadolinium contrast routinely: It is not necessary for conventional MRI in TBI 1
• Do not delay MRI in patients with normal CT but persistent neurologic findings: Early MRI improves prognostic accuracy 1, 3