How should I assess and manage a patient with head trauma, including criteria for urgent non‑contrast head CT and subsequent treatment?

Assessment and Management of Head Trauma

Initial Assessment Using Clinical Decision Rules

For patients with mild head trauma (GCS 13-15), obtain an urgent non-contrast head CT if any of the following high-risk or medium-risk criteria are present, as these validated decision rules identify 100% of patients requiring neurosurgical intervention. 1

High-Risk Criteria (Canadian CT Head Rule)

Obtain immediate CT if any of the following are present:

• Failure to reach GCS 15 within 2 hours of injury 1
• Suspected open or depressed skull fracture 1
• Any sign of basilar skull fracture (hemotympanum, raccoon eyes, Battle's sign, CSF otorrhea/rhinorrhea) 1
• Vomiting ≥2 episodes 1
• Age >64 years 1

Medium-Risk Criteria (New Orleans Criteria)

For patients with GCS 15 and witnessed loss of consciousness or amnesia, obtain CT if any of:

• Headache 1, 2
• Any vomiting 1, 2
• Age >60 years 1, 2
• Drug or alcohol intoxication 1, 2
• Short-term memory deficits 1, 2
• Physical evidence of trauma above the clavicles 1, 2
• Post-traumatic seizure 1, 2

Additional High-Risk Features (NEXUS Head CT)

Also obtain CT for:

• Focal neurologic deficit (including anisocoria) 1, 2
• Coagulopathy or anticoagulant use 1, 2
• Scalp hematoma 1
• Abnormal behavior or altered level of alertness 1

Imaging by Severity

Mild Traumatic Brain Injury (GCS 13-15)

• No imaging required when clinical decision rules indicate low risk 1, 2
• Non-contrast head CT is the appropriate initial study when any clinical decision rule criteria are met 1, 2
• Sensitivity of these rules approaches 100% for detecting neurosurgically significant injuries 1

Moderate to Severe TBI (GCS 3-12)

• Always obtain immediate non-contrast head CT regardless of mechanism 1, 3
• Add CT angiography of head and neck if vascular injury risk factors present (cervical spine fracture, unexplained focal deficit, Horner syndrome, Le Fort II/III fracture, basilar skull fracture) 3
• Perform cervical spine CT as part of initial imaging protocol 3

Critical Management Pitfalls

Warning Signs in GCS 15 Patients

Even with initial GCS 15, urgent neurosurgical intervention may be needed (0.2% of cases) if the following develop:

• Any decrease in GCS within 6 hours (present in 82% of deteriorating patients) 4
• Confusion or restlessness (64% and 36% respectively) 4
• Severe headache (45%) 4
• Focal temporal blow (36%) 4

Limitations of Normal CT

A normal head CT does not exclude traumatic brain injury, particularly:

• Diffuse axonal injury (only 10% visible on CT; >80% lack macroscopic hemorrhage) 1
• Microhemorrhages (require susceptibility-weighted MRI) 5
• Small cortical contusions near skull base 1
• Up to 27% of mild TBI patients with normal CT show abnormalities on early MRI 1

Follow-Up Imaging Protocols

Patients with Normal Initial CT and Stable Exam

• Routine repeat CT is NOT indicated if neurologic exam remains normal 1
• Risk of delayed deterioration is extremely low (0.04%) 1
• Exception: Patients on anticoagulation warrant observation and consideration of repeat CT at 24 hours, though even this risk is low (0.3%) 1

Patients with Positive Initial CT

• Repeat CT is indicated for:

  • Any neurologic deterioration 1, 3
  • Moderate to severe TBI (routine follow-up) 1
  • Anticoagulated patients (3-fold higher progression rate: 26% vs 9%) 1

• Routine repeat CT may be omitted in mild TBI with small hemorrhage (<10 mL), normal exam, and no anticoagulation 1

When to Obtain MRI

Non-contrast brain MRI is appropriate when:

• Persistent neurologic deficits unexplained by CT (subacute/chronic phase) 1
• GCS remains <15 after 24 hours despite normal CT 1
• Prognostication needed in mild TBI with normal CT but persistent symptoms 1
• Use T2, susceptibility-weighted imaging (SWI), and diffusion-weighted sequences* for optimal detection of axonal injury 3

Disposition Decisions

Safe for Discharge

Patients may be discharged when:

• GCS 15 with normal neurologic exam AND normal CT (deterioration risk 0.006%) 1, 2
• Provide written discharge instructions (23% of mild TBI patients poorly recall verbal instructions) 5
• Ensure responsible adult supervision for 24 hours 5

Requires Admission

• Any abnormality on CT 1
• GCS <15 at any point (observe with half-hourly neuro checks until GCS 15 achieved) 1
• Anticoagulated patients even with normal initial CT 1
• Moderate to severe TBI (GCS 3-12) 3

Severe TBI-Specific Management

Maintain systolic blood pressure >110 mmHg throughout evaluation, as hypotension worsens outcomes 3

Consider early CTA even without classic risk factors in severely injured patients with limited neurologic examination 3

If CTA is normal but vascular injury suspected, complete workup with MRA or digital subtraction angiography 3