Neurology · Trauma and Spinal Cord Injury
The facts most likely to be tested
Spinal shock presents as the immediate, transient loss of all reflex activity and flaccid paralysis below the level of injury.
Neurogenic shock is characterized by hypotension and bradycardia resulting from the loss of sympathetic tone in injuries at or above T6.
Central cord syndrome typically occurs in elderly patients with hyperextension injuries, manifesting as disproportionate upper extremity motor deficits compared to lower extremities.
Anterior cord syndrome presents with loss of pain and temperature sensation and motor function below the lesion, while dorsal column function (vibration and proprioception) remains intact.
Brown-Séquard syndrome (hemicord lesion) results in ipsilateral motor and proprioception loss with contralateral pain and temperature loss.
Methylprednisolone is no longer recommended as a standard of care for acute spinal cord injury due to the lack of proven benefit and increased risk of infectious complications.
Autonomic dysreflexia is a life-threatening emergency in patients with injuries above T6 triggered by noxious stimuli (e.g., bladder distension), presenting with paroxysmal hypertension and bradycardia.
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A 24-year-old male is brought to the emergency department after a high-speed motor vehicle collision. Physical examination reveals flaccid paralysis of all four extremities, absent deep tendon reflexes, and a blood pressure of 85/50 mmHg with a heart rate of 48 bpm. The patient has no sensation below the clavicles. A Foley catheter is placed, and the patient remains hemodynamically unstable despite fluid resuscitation.
What is the most likely diagnosis for the patient's hemodynamic status?
Neurogenic shock
The patient exhibits the classic triad of hypotension, bradycardia, and loss of sympathetic tone, which defines neurogenic shock following a high-level spinal cord injury.
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Etiology / Epidemiology
Primary causes are motor vehicle accidents and falls. High-risk groups include young males and the elderly with cervical spondylosis.
Clinical Manifestations
Assess for spinal shock (flaccid paralysis) and neurogenic shock (hypotension/bradycardia). Loss of perianal sensation indicates complete injury.
Diagnosis
MRI spine is the gold standard for soft tissue/cord evaluation. CT spine is the initial screening tool for bony fractures.
Treatment
Maintain MAP 85-90 mmHg for 7 days to ensure perfusion. Avoid steroids (no longer recommended for routine use).
Prognosis
Assess using ASIA Impairment Scale. Autonomic dysreflexia is a life-threatening complication in injuries above T6.
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Epidemiology & Etiology
Traumatic injury is most common in young males due to motor vehicle accidents. In the elderly, low-energy falls causing central cord syndrome are increasingly prevalent. Pre-existing cervical stenosis significantly increases risk of injury from minor trauma.
Pertinent Anatomy
The spinal cord terminates at the L1-L2 level; injuries below this cause cauda equina syndrome. The corticospinal tract mediates motor function, while the spinothalamic tract carries pain and temperature.
Pathophysiology
Primary injury occurs at the moment of impact via compression or laceration. Secondary injury follows due to ischemia, excitotoxicity, and inflammation. Maintaining spinal cord perfusion pressure is critical to prevent secondary neuronal death.
Clinical Manifestations
Evaluate for spinal shock, characterized by transient loss of all reflex activity below the lesion. Neurogenic shock presents with hypotension and bradycardia due to loss of sympathetic tone. Red flags include priapism, loss of sphincter tone, and saddle anesthesia.
Diagnosis
CT spine without contrast is the initial study for bony integrity. MRI spine is the gold standard for evaluating cord compression, hematoma, or ligamentous injury. Always obtain full spine imaging if the patient is obtunded or has a distracting injury.
Treatment
Stabilize the spine with a cervical collar and log-rolling. Maintain MAP 85-90 mmHg for 7 days to optimize cord perfusion. Avoid high-dose methylprednisolone due to lack of benefit and increased risk of infection and hyperglycemia.
Prognosis
Use the ASIA Impairment Scale (A-E) to grade severity. Monitor for autonomic dysreflexia (hypertension, bradycardia, headache) triggered by bladder distention. Deep vein thrombosis prophylaxis is mandatory.
Differential Diagnosis
Cauda Equina Syndrome: saddle anesthesia and bowel/bladder incontinence
Central Cord Syndrome: motor deficits greater in upper extremities than lower
Brown-Sequard Syndrome: ipsilateral motor loss and contralateral pain/temp loss
Anterior Cord Syndrome: loss of pain/temp with preserved proprioception
Transverse Myelitis: rapid onset weakness/sensory level without trauma