Cauda Equina
by Dr. Richard Bram and Dr. Farrah Nasrollahi
uploaded by Matthew Lam, MS2
Background
In adults, the spinal cord ends at the level of the first or second lumbar vertebral bodies
Injuries to L2 frequently damage the conus medullaris
Injuries below L2 usually involve the cauda equina and represent injuries to spinal roots rather than to the spinal cord
LOF of 2 or more of the 18 nerve roots
Causes:
Compression from:
Disc herniation/rupture, spinal stenosis
Tumors, infection, hemorrhage
Iatrogenic injury
At Risk Populations
Trauma
Underlying structural spinal diseases
Recent spinal/back surgery
IVDU
Underlying inflammatory conditions
Ankylosing spondyloarthropathy
Sarcoid
Underlying Malignancy
For a diagnosis of CES, one or more of the following should be present:
Bowel and/or bladder dysfunction
Reduced sensation in saddle area
Sexual dysfunction, with possible neuro deficit in lower limb
Presentation
Symptoms
LMN signs predominate in CES (conus medullaris may present with more mixed upper and lower motor neuron sxs)
Hyporeflexia
Marked asymmetric lower extremity weakness
Gradual onset of back pain with radicular pattern
LATE onset bowel and bladder dysfunction such as urinary retention and saddle anesthesia S3-5 roots (compared to conus medullaris)
Imaging
Patient Presentation
Patient: RH, 24 y.o.
PMHx: Morbid Obesity, Asthma, HTN, OSA
PSgHx: Chiari Decompression 2009, Tonsillectomy
Meds: None
Allergies:None
SH:Non-smoker, +Chewing Tobacco, + alcohol use, Denied illicit drug use
FH: Significant for HTN, DM, Obesity and CHF
HPI
4 days prior to presentation (Sunday), was helping to lift another person when he felt something pulled in his back.
The following day (Monday), he heard a pop in his back when getting out of his bed with subsequent weakness. He was not able to get out of bed until Tuesday when he went to the hospital.
He was seen at OSH and discharged with pain medications. On Wednesday early morning, he was unable to urinate or have a bowel movement.
He then returned to the hospital where an MRI was obtained which showed an L4-5 herniated disc with associated lumbar spinal stenosis.
Physical Examination
Significant for slightly decreased dorsiflexion in LLE (4+/5). Otherwise, strength was 5/5
Sensation was slightly decreased in the LLE throughout
No saddle anesthesia
Intact rectal tone
Hospital Course
Taken to OR emergently for L2-L5 laminectomies with L4-L5 discectomy
Discharged on hospital day 5
Was full strength but had persistent urinary retention
Seen in clinic 2 weeks after discharge
Remained full strength, urinary retention issues resolved
Persistent numbness in LLE
Clinical Questions
Cauda Equina is a rare condition with a disproportionately high medico-legal profile, how can we keep our sensitivity high in screening for this rare condition?
How should we be screening these people in the ED and what should their subsequent workup entail? Imaging (US, MRI), timing emergency surgery?
Does providing early emotional support for possible subsequent complications such as urogenital dysfunction reduce incidence of medico-legal pursuits?
References
Gardner A, Gardner E, Morley T. Cauda equina syndrome: a review of the current clinical and medico-legal position. European spine journal. 2011;20(5):690-697. doi:10.1007/s00586-010-1668-3.