Brown-Sequard Syndrome: Hemisection of the Cord

Brown-Sequard syndromeBrown-Sequard Syndrome

Injury to half the spinal cord, or “hemisection of the cord,” can occur with trauma, tumor, or disc herniation. But most often it is seen in textbooks and in med school exams! The injury produces a unique constellation of findings: loss of motor and fine touch on the same side as the injury, and loss of pain/temperature on the opposite side. This is the Brown-Sequard syndrome.

Here’s how it happens.

First to orient you to the cartoons. We all know what this is.

The Brain, actually!

The brain, actually!

And now the brain with the brainstem and spinal cord.

Brain, brainstem, spinal cord

Of all the tracts in the spinal cord, there are really only three you need to know to get started. There is one efferent pathway, the corticospinal tract that carries motor signals from the brain to the body. There are two afferent pathways that carry sensory information to the brain, the dorsal columns which carry proprioception and fine touch, and the spinothalamic tract which transmits pain and temperature.

Note the location of the “crossover” of these tracts. This crossover point is the key to understanding the clinical features of the Brown-Sequard syndrome. The corticospinal tract and the dorsal columns cross over in the medulla, at the “decussation of pyramids.”

Corticospinal tract

Dorsal columns

By contrast, the spinothalamic tract doesn’t cross to the opposite side until it exits from the cord.

Spinothalamic tract

So what if you have an injury to the left side of the cord. What will be the expected clinical findings? What neuro deficits will result?

Left hemisection of the cord

This is the Brown-Sequard syndrome. Loss of motor and fine touch ipsilateral to the lesion, and contralateral loss of pain and temperature.Ipsilateral loss of motor and fine touch

When the Pain Is Worse than Films

When the Pain Is Worse than Films

Sometimes a patient will have excruciating pain, and rather bland films. Then your job is to make sense of the mismatch.

Secondary Gain

In some cases, “secondary gain” can motivate a patient to exaggerate their symptoms. The patient may receive compensatory pay for an injury that occurred while working. Maybe he or she gains sympathy from a significant other. I’ve seen cases where a passive spouse unconsciously employs a pain syndrome to get revenge on their abusive, controlling partner. The pain brings a benefit to the sufferer, and that benefit is the “secondary” gain.

However, secondary gain is always a diagnosis of exclusion. You may suspect it from the beginning, but in every case you are obligated to look for an underlying physiologic reason for the pain. Only after you have ruled out other causes of pain can you conclude the patient is seeking secondary gain.

Occult Fracture

She dove into water four feet deep, skinning her nose and chin. Stunned, she came back up to the surface complaining of terrible neck pain. Friends took her to the ER and this x-ray was obtained.

X-ray: Lateral C Spine

The plain X-ray looked normal

Her C spine was cleared and she was discharged. Over the next couple of days her neck pain persisted. Someone suggested chiropractic care, but first she sought the advice of a physician friend who recommended a CT scan. Here it is, showing a fracture of C7, with a traumatic subluxation of C7 on T1. Of great significance, the fracture was missed on the plain x-ray, which was technically perfect with visualization down to the C7-T1 disc.

CT C Spine Sagittal reconstruction

Discitis

A 35 year old male with degenerative disc disease had been treated with some epidural steroid injections. Two injections gave partial relief for a couple of days, but within a month he worsened considerably. When we saw him, he was in severe pain, begging us for surgery. His MRI never looked that bad, and his worsening pain was curious to us. It didn’t all add up.Lumbar sagittal T1 without

So we sent him for another MRI without and with contrast, and blood work including CBC and Sed Rate. What was our suspicion? Infection or cancer. The pain was that bad. Sure enough, the MRI  showed enhancement about the L4-5 disc. It seems his run of the mill painful disc worsened due to an iatrogenic infection. Lumbar MRI T1 sagittal with contrastWe sent him for cultures and immediately started empiric antibiotics. He gradually improved over a full six weeks. No surgery was performed.

Spinal metastasis

If spine pain develops in someone with known, think spinal metastasis! The spinal pain of metastatic cancer is usually localized, without radicular or dermatomal radiation. It is worse at night while supine and better during the day. There may be dermatomal radiation if a spinal nerve is involved, or myelopathy if the cord is compressed. But usually the patient will complain of spine pain, worse at night. That alone is sufficient to warrant an MRI of the spine, without and with contrast, to evaluate spinal metastasis.MRI T spine without. Old T10 fracture

This 55 year old male had a T10 fracture a couple of years ago. He now presents with spine pain at night. MRI T spine is ordered, along with CT T spine. The cancers well known for metastasis to the spine are prostate, breast, and lung. Be on high alert in a patient with a history of cancer who now presents with new spinal pain.!MRI T spine. T1 with Contrast. Old fx T10. New cancer T12MRI T spine T1 with contrast. Old fx T10. New cancer T12CT axial shows invasion (lysis) of left T12 pedicle

The CT T spine confirms the lytic lesion of the left T12 pedicle, corresponding to the increased signal intensity on the MRI. The patient was sent for immediate radiation therapy for spinal metatstasis. He did not require surgery.

When pain exceeds imaging

When pain exceeds imaging, think FIRST –fracture–infection — cancer–as causes of spine pain. Check these out with MRI without and with contrast, CT, and even nuclear medicine bone scan. If, and only if, all these come back normal, then consider issues of malingering and secondary gain. But remember, your FIRST job is to find what others have missed or overlooked: occult fracture, infection, and cancer.