What are the differential diagnoses for a young adult with acute onset quadriplegia and no significant past medical history following a traumatic injury?

Acute Onset Quadriplegia Following Traumatic Injury: Differential Diagnoses

In a young adult with acute onset quadriplegia following traumatic injury and no significant past medical history, the primary differential diagnoses are spinal cord injury (particularly cervical spine fracture-dislocation), brainstem stroke (specifically midline pontine or medullary infarction), and diffuse axonal injury, with spinal cord injury being the most likely and requiring immediate imaging and stabilization. 1, 2, 3

Immediate Priorities in Traumatic Quadriplegia

Spinal Cord Injury (Most Common in Trauma Setting)

Cervical spine fracture-dislocation is the predominant cause of traumatic quadriplegia and must be ruled out immediately. 2

• Cervical spine fracture-dislocation accounts for the vast majority of traumatic quadriplegia cases, with 107 of 123 traumatic quadriplegia patients (87%) in one series having cervical fracture-dislocations 2
• Approximately 10% of traumatic quadriplegia cases involve neck injuries with no visible bone damage on initial radiographs, emphasizing the need for advanced imaging 2
• Critical timing consideration: Neurological deficits can develop or worsen 30 minutes or more after initial injury if spinal perfusion pressure is not maintained, particularly in the presence of hypotension 3
• Maintain systolic blood pressure >110 mmHg to ensure adequate spinal cord perfusion and prevent secondary injury 4, 5, 3

Prognostic Assessment at 72 Hours

The neurological examination at 72 hours post-injury is the most reliable predictor of long-term recovery. 2

• Among cognitively intact patients with complete spinal cord injury at 72 hours, none were walking at 1 year 2
• Patients with sensory incomplete function at 72 hours had a 47% chance of walking at 1 year 2
• Patients with motor incomplete function at 72 hours had an 87% chance of walking at 1 year 2
• Important caveat: Concurrent head injury (present in 10% of cases) makes initial neurological assessment unreliable and can lead to underestimation of potential recovery 2

Brainstem Stroke (Rare but Critical Differential)

Midline brainstem infarction involving the medulla oblongata or pons can cause acute quadriplegia and must be considered, especially if spinal imaging is negative. 1

• Specific anatomical locations: Bilateral pyramidal pathway involvement at the medullary or pontine level causes quadriplegia 1
• The typical MRI appearance is a "heart appearance sign" on axial imaging 1
• Key distinguishing features: Look for accompanying cranial nerve deficits, which help localize the lesion to the brainstem rather than spinal cord 1
• Primary etiology is atherothrombosis of the intradural vertebral artery and perforating branches 1
• Critical point: Cranial nerve-innervated muscles and sensory/cognitive functions are typically preserved in spinal cord injury but may be affected in brainstem stroke 6

Diffuse Axonal Injury (Consider with Severe Head Trauma)

Diffuse axonal injury should be considered when there is severe head trauma with unexplained neurological findings despite normal initial CT. 4, 5

• Non-contrast CT is the mandatory first-line imaging but detects only 10% of diffuse axonal injury cases 4, 5
• MRI is indicated when CT is normal but persistent unexplained neurologic findings are present, with optimal sequences including T2*-weighted gradient-echo, susceptibility-weighted imaging, and diffusion-weighted imaging 4, 5
• MRI can detect diffuse axonal injury lesions within the first 24 hours after injury 4
• Grade III diffuse axonal injury is associated with poor outcomes and highest mortality 4

Less Common Differentials in Trauma Setting

Guillain-Barré Syndrome (Unlikely but Possible)

• Guillain-Barré syndrome can present with acute lower motor neuron quadriparesis but is extremely rare in the immediate post-trauma setting 7
• Key distinguishing feature: Areflexia and ascending paralysis pattern, typically without sensory level 7
• Consider only if spinal and brainstem imaging are negative and clinical course is atypical for traumatic injury 7

Critical Illness Myopathy (Not Acute Presentation)

• Acute quadriplegic myopathy occurs after prolonged treatment with neuromuscular blocking agents and corticosteroids in the ICU setting, not as an acute presentation 6
• This diagnosis is relevant for delayed quadriplegia developing days to weeks after ICU admission, not for acute onset at time of injury 6

Immediate Diagnostic Algorithm

1. Stabilize and maintain spinal perfusion:

• Maintain systolic blood pressure >110 mmHg 4, 5, 3
• Avoid hypotension, which can cause delayed or worsening neurological deficit 3

2. Obtain immediate non-contrast CT of cervical spine and head:

• CT is the mandatory first-line imaging for suspected spinal cord injury 4, 5
• Include head CT if there is any alteration in consciousness or mechanism suggests head injury 8, 9

3. Perform detailed neurological examination:

• Document motor and sensory levels precisely 2
• Assess for cranial nerve deficits (suggests brainstem involvement) 1
• Note presence of reflexes (absent in spinal shock, may be present in brainstem stroke) 1

4. If CT is negative but quadriplegia persists:

• Obtain urgent MRI of cervical spine and brainstem 4, 5
• MRI will detect spinal cord injury without radiographic abnormality, brainstem infarction, and diffuse axonal injury 4, 5, 1

5. Reassess at 72 hours post-injury:

• The 72-hour neurological examination is the most reliable predictor of long-term outcome 2
• Document complete vs. incomplete injury and motor vs. sensory preservation 2

Critical Pitfalls to Avoid

• Do not assume normal initial neurological examination rules out evolving injury: Deficits can develop 30+ minutes after trauma if perfusion is inadequate 3
• Do not rely solely on plain radiographs: 10% of traumatic quadriplegia cases have no visible bone damage on initial x-rays 2
• Do not assume all post-trauma quadriplegia is spinal cord injury: Brainstem stroke can occur with trauma and requires different management 1
• Do not delay imaging for "clinical clearance": Immediate imaging is essential even if initial examination seems reassuring 4, 5