Cauda equina syndrome is a rare emergency with devastating consequences
Early recognition is paramount as the presence of bladder dysfunction portends bad functional outcomes
The presence of bilateral lower extremity weakness or sensory changes should alert clinicians to the diagnosis. Saddle anesthesia (or change in sensation) and any bladder/bowel changes in function should also raise suspicion for the disorder
MRI is the diagnostic modality of choice though CT myelogram can be performed if necessary
Prompt surgical consultation is mandatory for all patients with cauda equina syndrome regardless of symptoms at presentation
Bladder dysfunction (retention and/or incontinence) – up to 92% (Korse 2017)
Disruption of autonomic innervation leads to retention and overflow incontinence
Bowel dysfunction (constipation and/or incontinence) – up to 74% (Korse 2017)
Decreased sensation in the perianal area – up to 93% (Korse 2017)
Sexual dysfunction (i.e. impotence)
Physical Exam
Lower extremity weakness, numbness or paresthesias (usually bilateral)
Decreased or absent lower extremity reflexes
Hypotonia/atrophy of the lower extremities (in chronic presentations)
Urinary retention (increased post void residual)
Saddle anesthesia: Reduced or absent sensation in the perineal area (S2-S4 innervation)
Decreased or absent rectal tone
Differential Diagnosis (non-compressive causes of spinal cord dysfunction)
Multiple Sclerosis
Transverse Myelitis
Myelopathies (e.g. HIV related)
Spinal cord infarction
Spinal AVM
Syringomyelia
ED Evaluation and Management
Imaging
Bladder US
Normal post-void residual (PVR) < 50 ml (may be up to 100 ml in patients > 65 years)
PVR = 0.5 X AP diameter X lateral diameter X sagittal diameter of the bladder
Plain X-rays and CT scans can show bone and soft tissue abnormalities but not spinal cord abnormalities
CT Myelogram
Allows for visualization of the spinal cord and associated abnormalities
Requires spinal tap followed by injection of contrast. This limits it’s utility
Can be used for patients who have contraindications for MRI or when MRI unavailable
MRI
Imaging modality of choice for cauda equine syndrome
Image types: Obtain sagittal and axial T1 and T2 sequences
Neurosurgical or orthopedic consultation for emergency surgery
Surgery should be performed within 24 hours to increase the chance of better outcomes (Todd 2005)
The presence of urinary retention/incontinence at presentation is a predictor of poor outcomes
Take Home Points
Cauda equina syndrome is a rare emergency with devastating consequences
Early recognition is paramount as the presence of bladder dysfunction portends bad functional outcomes
The presence of bilateral lower extremity weakness or sensory changes should alert clinicians to the diagnosis. Saddle anesthesia (or change in sensation) and any bladder/bowel changes in function should also raise suspicion for the disorder
MRI is the diagnostic modality of choice though CT myelogram can be performed if necessary
Prompt surgical consultation is mandatory for all patients with cauda equina syndrome regardless of symptoms at presentation
Perron AD, Huff JS: Spinal Cord Disorders, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2010, (Ch) 106: p 1419-30.
References
Lavy C et al. Cauda Equina Syndrome. BMJ 2009; 338: PMID: 19336488
Todd NV. Cauda equina syndrome: the timing of surgery probably does influence outcome. Br J Neurosurg 2005;19:301-6 PMID: 16455534
Korse NS et al. Cauda Equina Syndrome: presentation, outcome and predictors with focus on micturition, defecation and sexual dysfunction. Eur Spine J 2017; 26(3): 894-904. PMID: 28102451
Images
Traumatic Burst Fracture: Case courtesy of Dr Ian Bickle, <a href=”https://radiopaedia.org/”>Radiopaedia.org</a>. From the case <a href=”https://radiopaedia.org/cases/25701″>rID: 25701</a>
Lumbar Disc Herniation Case courtesy of A.Prof Frank Gaillard, <a href=”https://radiopaedia.org/”>Radiopaedia.org</a>. From the case <a href=”https://radiopaedia.org/cases/6754″>rID: 6754</a>
Lumbar Disc Herniation II Case courtesy of A.Prof Frank Gaillard, <a href=”https://radiopaedia.org/”>Radiopaedia.org</a>. From the case <a href=”https://radiopaedia.org/cases/13942″>rID: 13942</a>
Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter: @srrezaie)