Assessment and Diagnosis

The initial assessment and stabilization of TBI patients follows the ABCDE approach:

• A – Airway: Ensure patent airway. Hypoxia can worsen neurological outcomes and increase mortality.
• B – Breathing: Assess oxygen saturation, respiratory rate, and chest expansion. Supplemental oxygen or mechanical ventilation may be required.
• C – Circulation: Monitor blood pressure, heart rate, peripheral perfusion. Fluid resuscitation or vasopressors may be needed to maintain cerebral perfusion.
• D – Disability: Assess level of consciousness with Glasgow Coma Scale (GCS) and pupillary examination. Provides information on severity of injury.
• E – Exposure: Remove clothing, inspect for external injuries. Maintain normothermia and prevent infection.

Glasgow Coma Scale

The Glasgow Coma Scale (GCS) is a widely used tool to assess level of consciousness and severity of TBI. It consists of three components:

• Eye opening score (1-4)
• Verbal response score (1-5)
• Motor response score (1-6)

Total score ranges from 3 (deep coma) to 15 (fully awake person). Lower scores indicate more severe impairment and have been shown to correlate with mortality, disability, and functional outcome after TBI.

Pupillary Examination

Pupillary examination involves assessing:

• Size
• Shape
• Reactivity to light

Abnormal findings like anisocoria, mydriasis, or miosis can indicate:

• Intracranial lesions
• ↑ Intracranial pressure
• Brainstem dysfunction

Pupillary exams help identify type and location of brain injury.

Neuroimaging

Neuroimaging is essential for diagnosis, prognosis, and follow-up. Modalities include:

CT

• Fast, widely available
• Sensitive for detecting acute hemorrhage, fractures, mass effect
• Limited for non-hemorrhagic injuries
• Normal CT
  • No evidence of bleeding, swelling, or structural damage
• Abnormal Findings
  • Skull Fractures: Linear or depressed skull fractures may be evident, particularly in more severe cases.
  • Intracranial Hemorrhage: This can include epidural hematoma (usually biconvex in shape, often associated with arterial injury), subdural hematoma (crescent-shaped, associated with venous bleeding), subarachnoid hemorrhage (blood in the subarachnoid space, often appearing as areas of increased density over the brain surface), or intraparenchymal hemorrhage (bleeding within the brain tissue itself).
  • Cerebral Contusions: These are small, punctate areas of hemorrhage within the brain, often located at the site of direct impact or at a site opposite the impact (coup-contrecoup injury).
  • Cerebral Edema: Swelling of the brain tissue, which may lead to increased intracranial pressure. It appears as areas of decreased density.
  • Brain Herniation: Displacement of brain tissue from its normal location, which can be life-threatening. This might include signs like cingulate herniation under the falx cerebri or uncal herniation into the tentorium.

MRI

• More sensitive than CT
• Better for non-hemorrhagic pathology
• Provides info on extent/location of injury, recovery potential
• Less accessible acutely, safety/monitoring challenges
• Abnormal Findings
  • Diffuse Axonal Injury (DAI): MRI is particularly sensitive to DAI, which appears as multiple small, scattered white matter lesions on T2-weighted images. These lesions represent shearing of axons due to rotational forces during injury.
  • Microhemorrhages: Small areas of bleeding that might not be visible on CT can be detected on MRI, especially with susceptibility-weighted imaging (SWI) or gradient echo sequences.
  • Non-Hemorrhagic Contusions: Bruising of the brain tissue without significant bleeding can be better visualized on MRI.
  • Post-Traumatic Brain Atrophy: Over time, MRI can show loss of brain volume which is indicative of the chronic effects of TBI.
  • Shearing Injuries: MRI can detect subtle injuries to the white matter tracts of the brain, which might be missed on CT scans.