Most patients with back pain in the ED have benign, self-limiting conditions. But occasionally, a patient has cauda equina syndrome (CES) — a neurosurgical emergency that rookies must not miss. Delay in recognition can lead to permanent paralysis, incontinence, and loss of sexual function.
What Is Cauda Equina Syndrome?
- Compression of the lumbosacral nerve roots within the spinal canal.
- Causes:
- Large central herniated disc (most common).
- Trauma.
- Spinal stenosis.
- Epidural abscess or hematoma.
- Tumors/metastases.
Why It Matters
- Time-sensitive: early decompression (<24–48 hrs) improves bladder and motor recovery.
- Missed diagnosis = permanent disability and medicolegal risk.
Classic Red Flags
Motor/Sensory
- Bilateral leg weakness (often asymmetric early).
- Numbness/tingling in saddle area (perineum, buttocks, inner thighs).
- Loss of ankle reflexes.
Autonomic Dysfunction
- Urinary retention (most reliable symptom).
- Overflow incontinence (late).
- Fecal incontinence.
- Sexual dysfunction.
Pain
- Severe low back pain with sciatica (often bilateral).
Rookie pearl: Saddle anesthesia + urinary retention = CES until proven otherwise.
ED Evaluation
- Focused neuro exam: motor strength, reflexes, sensation (esp. perineal), anal tone.
- Check post-void residual (PVR) bladder scan — >200 mL suggests retention.
- Labs: only if infection or abscess suspected (CBC, ESR/CRP, cultures).
- Imaging: Urgent MRI lumbosacral spine (gold standard). CT myelogram if MRI unavailable.
ED Management
- Call neurosurgery/spine surgery immediately if CES suspected.
- Steroids (dexamethasone 10 mg IV) if tumor or malignancy-related compression.
- Antibiotics if abscess suspected (cover MRSA + gram negatives).
- Analgesia, bladder catheterization if retention.
- Admit all patients — none are safe for discharge.
Common Rookie Mistakes
- Discharging back pain without asking about bladder/bowel symptoms.
- Skipping perineal/saddle sensory exam out of discomfort.
- Relying only on plain X-rays (misses almost all CES causes).
- Assuming urinary incontinence = UTI without considering CES.
- Delaying MRI until morning instead of emergent.
Rookie Pearls
- Always ask about bladder, bowel, sexual function in back pain patients.
- Urinary retention is the most specific red flag.
- MRI is the test of choice — get it urgently, not electively.
- Early surgical decompression saves function.
Take-Home Message
Cauda equina syndrome is a neurosurgical emergency masquerading as back pain. For rookies:
- Red flags = saddle anesthesia + urinary retention + bilateral sciatica/weakness.
- Get urgent MRI and neurosurgical consult.
- Never discharge a patient with suspected CES — time is nerve.
Remember: In back pain, always ask about pee, poo, and saddle — those answers can save a life.
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