What are the symptoms of cauda equina syndrome?

Symptoms of Cauda Equina Syndrome

Cauda equina syndrome presents with a constellation of symptoms including urinary retention (the most sensitive finding at 90%), saddle anesthesia, bilateral radiculopathy, and bowel/sexual dysfunction, with early recognition of "red flag" symptoms being critical before irreversible "white flag" symptoms develop. 1, 2, 3

Early Warning "Red Flag" Symptoms

These symptoms demand immediate MRI evaluation and neurosurgical consultation:

• Bilateral radiculopathy - bilateral leg pain radiating below the knee, bilateral sensory disturbance, or bilateral motor weakness in the lower extremities 1, 2, 3
• New changes in bladder function - hesitancy, poor stream, urgency, or any new difficulty with micturition while still maintaining some control 1, 2, 3
• Subjective and/or objective loss of perineal sensation - numbness or tingling in the "saddle" distribution (perineal/genital region) 1, 2, 3
• Progressive neurological deficits - worsening motor weakness or sensory loss in the legs 1, 2
• Low back pain - often severe and may overshadow leg pain, typically in lumbar nerve root distribution (sciatica) 1, 2

Late "White Flag" Symptoms (Indicating Established Damage)

These symptoms often indicate irreversible neurological damage has already occurred:

• Urinary retention - painless retention is particularly ominous; this is the most frequent finding in established CES with 90% sensitivity but represents advanced disease 1, 2, 3
• Complete urinary incontinence - total loss of bladder control 1, 2, 3
• Fecal incontinence - loss of bowel control 1, 2, 3
• Complete saddle anesthesia - total loss of sensation in the perineal region rather than partial sensory changes 1, 2
• Patulous anus - loss of anal tone on examination 3
• Sexual dysfunction - loss of sexual function 1, 4

Critical Clinical Pitfalls

• No single symptom has high positive predictive value in isolation - diagnosis requires clinical suspicion based on the combination of symptoms 1, 2, 3
• Waiting for urinary retention is a dangerous error - this is a late sign indicating advanced disease; act on earlier red flag symptoms 2
• Subtle perineal sensory changes are easily missed - sensory testing is subjective and requires careful examination 3
• Anal tone assessment has low interobserver reliability - especially among inexperienced clinicians, so don't rely on this alone 3
• Atypical presentations occur - some patients present with isolated bladder/bowel dysfunction without motor weakness, which can lead to delayed diagnosis when patients present to urology rather than spine surgery 5
• Symptoms develop gradually over weeks to months - the insidious onset can lead to attribution to more benign causes, delaying appropriate imaging 2

Staging and Prognosis

The syndrome progresses through stages with different outcomes:

• CESS (Suspected) - patients with red flag symptoms who receive early treatment typically achieve normal or socially normal bladder and bowel control 1, 2
• CESI (Incomplete) - patients still have some bladder control; outcomes are significantly better with early intervention 1, 2
• CESR (Complete with Retention) - patients have urinary retention; recovery is variable (48-93% show some improvement) but many require intermittent self-catheterization, manual fecal evacuation, and only a minority return to work 1, 2

Immediate Action Required

When red flag symptoms are present, immediate MRI without contrast is essential - do not delay imaging waiting for complete urinary retention to develop, as this represents a missed opportunity for optimal outcomes 1, 2, 3. Emergency decompressive surgery within 12-72 hours of symptom onset is associated with better outcomes compared to further delayed surgery 1, 2.