Brown-Sequard syndrome.

A 67-year-old otherwise healthy woman was assaulted with a knife, receiving multiple stab wounds. On arrival, vital signs were within normal limits. She was mentating appropriately. She complained of weakness to her right upper and lower extremities. Neurologic examination demonstrated 0/5 right triceps and grip strength to the right upper extremity and 0/5 motor strength throughout the entire lower extremity. Right sensory examination demonstrated hypesthesia at C7, anesthesia at C8 and T1, with hyperpathia T2 fading through the upper lumbar levels associated with complete proprioceptive loss. On the left, there was anesthesia at T4 and hypesthesia at T5 fading through the upper lumbar levels with retained left proprioception. Back examination demonstrated a 1 cm laceration to the left of midline at C7 with clear fluid leaking from the wound. MRI demonstrated abnormal signal at the C5–C6 level, consistent with traumatic injury secondary to stab wound.

Parasagittal short -T1 inversion recovery (STIR) MRI (figure 1) spinal cord hemisection at C6. Remaining portions of the imaged spinal cord appeared intact with no gross area of abnormal signal to suggest significant contusion or edema.

Figure 1

MRI demonstrating abnormal signal at the C5–C6 level, consistent with traumatic injury secondary to stab wound.

Bolus 2 L lactated Ringer’s solution and initiate norepinephrine given concern for neurogenic shock.

Obtain spine team consultation given concern for Brown-Sequard syndrome (BSS).

Initiate physical therapy given inability to walk.

Consult neurology given concern for acute-onset Guillian-Barre syndrome.

What we did and why

Correct answer: B

Complete spinal cord transection results in loss of sensory and motor function distal to the site of injury. Lateral hemisection syndrome, more commonly known as BSS, involves the dorsal column, corticospinal tract, and spinothalamic tract unilaterally. It results in weakness, loss of vibration and proprioception ipsilateral to, and loss of and temperature sensation contralateral to, the injury.

Based on examination and imaging findings, a diagnosis of spinal cord laceration with resultant BSS at C5–C6 was made. She was taken to the operating room to repair her dural laceration and was discharged to rehabilitation on postoperative day 3. She was seen in follow-up by neurosurgery 2 months later, at which time she demonstrated improving upper and lower extremity motor examinations. Vibratory sensation was returning. Proprioception remained absent in the right lower extremity.

BSS was described in 1855 by Charles-Edouard Brown-Sequard after experimentation with spinal cord hemisection in animals.1 There are three mechanisms by which a spinal cord injury (SCI) is propagated following penetrating spinal injury. First, direct damage caused by the weapon or bony fragments causes permanent physical cord damage. Second, the cord’s vascular supply is compromised, resulting in edema and ischemia. Third, cord contusion causes neurologic deficits. Although the neurophysiology of it is understood and the mechanism (secondary to spinal cord hemisection) is obvious, given the variability in the three aforementioned mechanisms, it is rare to see pure BSS with pure ipsilateral motor and contralateral sensory deficits.2

Each year, 11 000 cases of SCI occur in the USA.3 BSS is not common, but over 500 cases have been reported to date.4 Its true incidence is unknown; it has been estimated to constitute 1%–4% of traumatic SCIs,3 with the average age of affected patients around 40.3 Very few patients will actually exhibit pure BSS. ‘Brown-Sequard-Plus’ syndrome is appreciated more frequently, wherein there is a relative ipsilateral hemiplegia paired with a relative contralateral hemianalgesia.3

BSS is usually secondary to a penetrating SCI, but many other etiologies have been described. BSS may be caused by a cervical synovial cyst,5 a ruptured pheochromocytoma,6 transverse myelitis after influenza vaccination,7 and even as a rare manifestation of decompression sickness.8 Diagnosis is established based on classical examination findings and MRI.

Management is conservative with aggressive early rehabilitation. Surgical intervention is indicated in the presence of cerebrospinal fluid leak, persistent spinal cord/root compression, or progressive deterioration.2

BSS demonstrates a favorable prognosis compared with other types of incomplete SCI.9 10 In fact, it has the best prognosis of all the SCI syndromes,11 with >75% of patients walking without assistive devices after rehabilitation.10 11 It has been postulated that the most important predictive factor in terms of eventual functional status is whether the predominant plegic site was an upper or lower limb. In patients where the upper extremity is weaker than the lower extremity, walking at discharge is more likely.10 Recovery occurs as spinal cord edema resolves, with duration of recovery longer than 1–6 months.12