From the Guidelines
The evaluation of suspected cauda equina syndrome (CES) in the emergency department requires prompt recognition and management to prevent permanent neurological damage, and the most recent and highest quality study 1 recommends an immediate MRI of the lumbar spine as the gold standard imaging modality for diagnosing CES.
Step-by-Step Algorithm for Evaluating Suspected CES
The following steps should be taken when evaluating suspected CES:
- Begin with a focused history, asking about low back pain, bilateral leg pain or weakness, saddle anesthesia, and bowel or bladder dysfunction (particularly urinary retention or incontinence) as suggested by 1.
- Perform a thorough neurological examination including lower extremity strength, sensation (especially perineal and perianal areas), reflexes, and rectal tone.
- Check for post-void residual volume using bladder scan or catheterization if urinary retention is suspected; volumes greater than 100-200mL suggest retention.
- Order an immediate MRI of the lumbar spine, which is the gold standard imaging modality for diagnosing CES as recommended by 1.
- If MRI is unavailable, CT myelography can be considered as an alternative.
- While awaiting imaging, administer pain control with NSAIDs (such as ketorolac 30mg IV) and opioids if needed (morphine 0.1mg/kg IV).
- For patients with significant pain or neurological deficits, consider dexamethasone 10mg IV followed by 4mg every 6 hours to reduce inflammation.
- Consult neurosurgery or orthopedic spine surgery immediately when CES is suspected, even before imaging results are available.
- If CES is confirmed, surgical decompression should be performed urgently, ideally within 24-48 hours of symptom onset for the best outcomes.
Key Points to Consider
- CES is a true surgical emergency where delays in decompression can lead to permanent neurological deficits including paralysis, sexual dysfunction, and lifelong bowel and bladder incontinence.
- The most frequent finding in CES is urinary retention (90% sensitivity) as noted in 1.
- In patients without urinary retention, the probability of CES is approximately 1 in 10,000 as mentioned in 1.
- A recent prospective cohort study by Bell et al 1 recommends urgent MRI assessment in all patients who present with new-onset urinary symptoms in the context of low back pain or sciatica.
From the Research
Step-by-Step Algorithm for Evaluating Suspected Cauda Equina Syndrome (CES) in the Emergency Department (ED)
- Identify patients with suspected CES, characterized by symptoms such as bilateral neurogenic sciatica, reduced perineal sensation, altered bladder function, loss of anal tone, and loss of sexual function 2
- Perform a thorough clinical assessment, including history and examination findings, to identify red flags and findings consistent with CES 2, 3
- Use clinical features such as saddle sensory deficit, which has a higher predictive value in diagnosing CES, to guide the assessment 3
- Order postvoid bladder volume assessments to assist in the evaluation of CES 2
- Request magnetic resonance imaging (MRI) or computed tomography myelography if MRI is not available, to confirm the diagnosis of CES 2, 3, 4
- Empower ED senior decision makers to order MRIs prior to neurosurgical review, to reduce the time to diagnosis or exclusion of CES 4
- Develop a clinical pathway that coordinates care between the ED, radiology, and neurosurgical teams, to expedite the management of CES 4
- Consider the timing of cauda equina decompression, as delays in management can lead to significant irreversible disability 5
Key Considerations
- CES is a rare but emergent condition that requires timely and effective diagnosis and management to prevent permanent neurological dysfunction 6, 2
- Delays in diagnosis can have devastating consequences for patients and result in high cost negligence claims 6
- A practical approach to safety netting those at risk, including communication and documentation, is essential in the management of CES 6