Management of Loss of Consciousness After Motor Vehicle Collision
Patients with loss of consciousness after a motor vehicle collision require immediate neuroimaging, comprehensive trauma assessment, and appropriate specialist referral based on suspected etiology, with CT scan of the head being the primary diagnostic tool.
Initial Assessment and Stabilization
Primary Survey (ABCs)
- Ensure patent airway with cervical spine protection (assume cervical spine injury until proven otherwise) 1
- Assess breathing: respiratory rate, effort, oxygen saturation; provide supplemental oxygen if needed 1
- Evaluate circulation: pulse, blood pressure, capillary refill; control external hemorrhage; establish IV access if signs of shock 1
- Perform rapid neurological assessment including Glasgow Coma Scale (GCS)
Secondary Survey
- Complete head-to-toe examination to identify associated injuries
- Document duration of loss of consciousness (LOC)
- Obtain history from witnesses about the event, if available
- Assess for post-traumatic amnesia, which is a significant predictor of cognitive sequelae 2
Diagnostic Evaluation
Immediate Imaging
- CT scan of the head is the primary diagnostic tool for patients with LOC after MVC 3
- Indications for head CT in mild traumatic brain injury (MTBI) with LOC include:
- Any period of LOC (even brief)
- GCS score of 13-15 after LOC
- Loss of memory of events immediately before or after accident 3
- Abnormal mental state at time of accident (dazed, disoriented, confused)
Additional Testing
- Cervical spine imaging (CT or X-ray based on clinical suspicion)
- FAST (Focused Assessment with Sonography for Trauma) to detect intra-abdominal fluid 1
- Chest and pelvic radiographs to identify thoracic injuries and pelvic fractures 1
- Laboratory studies: CBC, coagulation studies, type and cross-match, arterial blood gases if respiratory distress 1
- ECG for all patients with LOC to evaluate potential cardiac causes 3
Differential Diagnosis and Specialist Referral
Traumatic Brain Injury
- Most common diagnosis in MVC with LOC 4
- Mild TBI (concussion) is frequently missed in the ED (up to 60% of cases) 4
- Patients with missed mTBI diagnosis develop more severe post-concussion symptoms 4
Cardiac Syncope
- Consider cardiac causes of LOC that may have preceded and caused the MVC 3, 5
- Patients with suspected cardiac cause for LOC should receive specialist cardiovascular assessment 3
Neurally-Mediated Syncope
- Vasovagal syncope can cause LOC while driving 5
- Patients with uncomplicated faint, situational syncope, or orthostatic hypotension should receive ECG but may not require immediate further investigation 3
Seizure
- Brief seizure-like activity is common during syncope and should not be automatically regarded as indicating epilepsy 3
- Patients with features suggesting epilepsy should be referred for specialist neurologic assessment 3
Management Plan
Immediate Management
- Stabilize based on trauma protocols
- Treat identified injuries
- Monitor for neurological deterioration
- Provide analgesia as needed
Disposition Decision
Admit patients with:
- Abnormal CT findings
- GCS < 15
- Persistent neurological deficits
- Multiple injuries
- Inadequate home supervision 1
Consider discharge for patients with:
- Normal neurological examination
- Normal CT scan
- GCS of 15
- No other significant injuries
- Adequate home supervision with reliable return precautions 1
Follow-up Care
- Arrange appropriate follow-up based on injuries identified
- Assess for acute stress reactions in both patient and family members 1
- Consider early psychological support, as emotional disorders are common after TBI 6
- Monitor for post-concussion symptoms, which may persist for months 7
- Common symptoms include: sleep disturbances, tiredness, dizziness, forgetfulness, headache, and neck pain 7
Special Considerations
- Missed diagnosis of mTBI is common in MVCs when patients present with other injuries 4
- Post-concussion syndrome develops in approximately 55% of patients with mTBI after MVC 4
- Risk factors for developing post-concussion syndrome include:
- Loss of consciousness
- Post-injury headache
- Post-traumatic stress disorder 4