Basics
Description
Compression of lumbar and sacral nerve fibers in cauda equina region:
- Nerve fibers below conus medullaris
- Fibers end at L1-L2 interspace.
Risk Factors
- Neoplasm
- IV drug use
- Immunocompromised state
- Trauma
Etiology
- Herniated disc most common:
- L4-L5 discs > L5-S1 > L3-L4
- Most common in 4th and 5th decades of life
- Mass effect from:
- Myeloma, lymphoma, sarcoma, meningioma, neurofibroma, hematoma
- Spine metastases (breast, lung, prostate, thyroid, renal)
- Epidural abscess (especially in IV drug users)
- Blunt trauma
- Penetrating trauma
- Spinal anesthesia
Diagnosis
Signs and Symptoms
History
- Low back pain
- Sciatica/radicular pain (unilateral or bilateral)
- Lower-extremity numbness or weakness
- Difficulty ambulating owing to weakness or pain
- Bladder or rectal dysfunction:
- Retention or incontinence
Physical Exam
- Lumbosacral (LS) tenderness
- Lower-extremity sensory or motor deficits:
- Decreased foot dorsiflexion strength
- Decreased quadriceps strength
- Decreased deep tendon reflexes
- Saddle hypalgesia or anesthesia
- Decreased anal sphincter tone
Essential Workup
- Neurologic exam most essential:
- Straight-leg raise
- Las ¨gue sign:
- With patient supine, flex hip and dorsiflex foot.
- Pain or spasm in posterior thigh indicates nerve irritation.
- Perineal sensation
- Rectal tone
- Anal wink: Reflex contraction of external anal sphincter with gentle stroking of skin lateral to anus
- Postvoid residual volume:
- Estimate by bladder catheterization or using US.
- >50-100 mL is considered abnormal.
- Residual increases with age.
- Diagnosis unlikely if normal
Diagnosis Tests & Interpretation
Lab
- Based on differential diagnoses
- CBC, urinalysis, ESR, and C-reactive protein (CRP)
Imaging
- Radiographs of LS spine
- MRI of spine is definitive study.
- CT myelogram if MRI unavailable
Differential Diagnosis
- Osteoarthritis, LS strain, sciatica
- Vertebral fracture (pathologic and nonpathologic)
- Osteomyelitis
- Spinal epidural abscess
- Conus medullaris or higher cord compression
- Ankylosing spondylitis, spinal stenosis
- Abdominal aortic aneurysm dissection
- Vascular claudication
- Hip pathology
- Acute transverse myelitis
Treatment
Pre-Hospital
- Manage airway and traumatic injuries as indicated.
- If evidence of trauma, patient should be transported with full spine immobilization.
Even in nontrauma patient, consider spinal immobilization given possibility of unstable lesion.
Initial Stabilization/Therapy
- Spine immobilization if trauma or unstable spine lesion suspected
- Analgesia
- NPO until evaluated by neurosurgery
Ed Treatment/Procedures
- Repeat neurologic exams to detect progression.
- For acute spinal cord trauma (<8 hr), begin high-dose methylprednisolone protocol.
- Immediate neurosurgical consultation in all cases
- Initiate antibiotics for epidural abscess in consultation with neurosurgery.
- Controversy exists regarding urgency of decompression:
- Recommendations range from within 6 hr of onset to within 24 hr.
Medication
- Methylprednisolone (high-dose steroid protocol): 30 mg/kg IV bolus, then 5.4 mg/kg/h infusion over next 23 hr. Should be started within 8 hr of injury.
Follow-Up
Disposition
Admission Criteria
- All patients with acute cauda equina syndrome must be admitted to neurosurgical service.
- Patients have good prognosis with rapid surgical decompression.
- Treatment should not be delayed.
- Patients presenting late (>48 hr) also benefit from surgical decompression.
Discharge Criteria
Patients with established cauda equina syndrome with prior complete evaluation and no new neurologic deficits may be discharged with close follow-up with their neurosurgeon.
Pearls and Pitfalls
Ideally, diagnose patients in early phase before irreversible neurologic dysfunction:
- Back pain out of proportion
- Fever and back pain
- Back pain in high-risk groups; screen with ESR/CRP when infection suspected
Additional Reading
- Fraser S, Roberts L, Murphy E. Cauda equina syndrome: A literature review of its definition and clinical presentation. Arch Phys Med Rehabil. 2009;90(11):1964-1968.
- Hussain SA, Gullan RW, Chitnavis BP. Cauda equina syndrome: Outcome and implications for management. Br J Neurosurg. 2003;17(2):164-167.
- Kingwell SP, Curt A, Dvorak MF. Factors affecting neurological outcome in traumatic conus medullaris and cauda equina injuries. Neurosurg Focus. 2008;25(5):E7.
- Ma B, Wu H, Jia LS, et al. Cauda equina syndrome: A review of clinical progress. Chin Med J (Engl). 2009;122(10):1214-1222.
- Mauffrey C, Randhawa K, Lewis C, et al. Cauda equina syndrome: An anatomically driven review. Br J Hosp Med (Lond). 2008;69(6):344-347.
- Olivero WC, Wang H, Hanigan WC, et al. Cauda equina syndrome (CES) from lumbar disc herniations. J Spinal Disord Tech. 2009;22(3):202-206.
- Rooney A, Statham PF, Stone J. Cauda equina syndrome with normal MR imaging. J Neurol. 2009;256(5):721-725.
- Todd NV. An algorithm for suspected cauda equina syndrome. Ann R Coll Surg Engl. 2009;91(4):358-359; author reply 359-360.
Codes
ICD9
- 344.6 Cauda equina syndrome
- 344.60 Cauda equina syndrome without mention of neurogenic bladder
- 344.61 Cauda equina syndrome with neurogenic bladder
ICD10
G83.4 Cauda equina syndrome
SNOMED
- 192970008 Cauda equina syndrome (disorder)
- 192971007 cauda equina syndrome not affecting bladder (disorder)
- 12454008 cauda equina syndrome with neurogenic bladder (disorder)
- 230614002 Injury of cauda equina (disorder)
- 126963001 Neoplasm of cauda equina (disorder)