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neuro.cauda-equina.v1PRODUCTION
neuro.cauda-equina.v1

Cauda Equina Syndrome

neurologyacuteadult
Hard-required inputs
0 / 15
Care setting:

Encounter flow

12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Adult with back pain + ≥1 red flag (bilateral sciatica / saddle change / urinary or bowel change / progressive deficit / new sexual dysfunction) — frame as time-critical surgical emergency until MRI excludes structural compression (NICE NG59; BASS Germon Spine J 2015 PMID 25708139)

Inputs
1
Actions
0
Advance rule
Set
Advance when

CES suspected + STAT pathway activated

Patient inputs (19)

Age frames pre-test priors — disc-herniation peak 30-50; metastatic CES rises with cancer-bearing populations >55 (BASS Germon 2015 PMID 25708139)

Acute severe lumbar back pain framing — "worst ever" framing more common in scan-negative functional CES (Hoeritzauer Neurology 2020/21 PMID 33177221)

Known cancer with new back pain + neuro deficit → MESCC overlay; dexamethasone bridge to RT/surgery (Loblaw IJROBP 2012 PMID 22420969)

Anticoagulation / recent epidural/spinal procedure → epidural-haematoma phenotype; anticoagulant reversal + emergent surgery (BASS Germon 2015 PMID 25708139)

IVDU / immunosuppression / indwelling catheter / recent procedure → epidural-abscess phenotype; IV antibiotics + emergent surgery (NICE NG59)

Hours-to-decompression correlates with bladder/bowel recovery — Srikandarajah Spine 2015 PMID 25646751: CESI <24 h had 11.1% bladder dysfunction vs 46.6% at >24 h; document precise onset

STAT MRI lumbosacral spine is the definitive test — no clinical rule substitutes (Lavy BMJ 2009 PMID 19336488; NICE NG59; BASS Germon 2015 PMID 25708139)

Bladder scan PVR — >200 mL supports CESR (retention with overflow); a load-bearing objective measure when subjective history is uncertain (BASS Germon 2015 PMID 25708139)

Baseline + infection workup if epidural-abscess phenotype suspected

Pre-surgical baseline + anticoagulant reversal trigger if haematoma phenotype (BASS Germon 2015 PMID 25708139)

Bilateral radicular leg pain is a core red flag — present in most CES (Todd 2017 PMID 28637110); unilateral sciatica is NOT CES until proven otherwise

Subjective perineal numbness/paraesthesia is an EARLY red flag (Todd 2017 PMID 28637110 — flag of warning); objective absent perineal pinprick is a LATE flag of often-irreversible CES

Urinary difficulty / hesitancy / loss of awareness of bladder filling = CESI (incomplete) red flag; complete painless retention with overflow = CESR — worse functional prognosis (BASS Germon 2015 PMID 25708139)

Faecal incontinence / loss of rectal sensation / inability to control gas — load-bearing late red flag (Lavy 2009 PMID 19336488)

Bilateral progressive motor weakness (≥1 MRC-grade drop) — surgical trigger (NICE NG59; Quaile 2019 PMID 30374638)

Functional-neurological-disorder signs / panic-attack symptoms at onset / "worst-ever" pain framing favour scan-negative CES — pivot from surgical to functional pathway AFTER negative MRI (Hoeritzauer 2020/21 PMID 33177221)

CT myelogram as alternative if MRI contraindicated (pacemaker / weight / claustrophobia escalation) (BASS Germon 2015 PMID 25708139)

Inflammation screen — supports epidural-abscess / discitis phenotype if elevated (NICE NG59)

New erectile / sensory dysfunction in the saddle distribution — under-asked red flag (BASS Germon 2015 PMID 25708139)

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (10)

10 need judgement
  • informationallife_threateningcesr_complete_painless_retention
    Complete painless urinary retention (CESR) with overflow incontinence + PVR usually >500 mL (BASS Germon Spine J 2015 PMID 25708139)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningbilateral_progressive_motor_deficit
    Bilateral lower-limb progressive motor weakness (≥1 MRC grade drop over hours) — surgical emergency irrespective of bladder status (Quaile Int Orthop 2019 PMID 30374638)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningphenotype_metastatic_mescc_overlay
    Known active malignancy with new CES → metastatic epidural spinal cord compression overlay (Loblaw IJROBP 2012 PMID 22420969)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningphenotype_epidural_haematoma
    CES on background of anticoagulation, antiplatelet therapy, or recent neuraxial procedure → epidural haematoma (BASS Germon Spine J 2015 PMID 25708139)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningphenotype_epidural_abscess
    CES with fever / IVDU / immunosuppression / recent procedure / indwelling vascular catheter → spinal epidural abscess (NICE NG59)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningabsent_perineal_sensation_or_complete_sphincter_loss_white_flag
    Absent perineal sensation and complete sphincter loss — "white flag" of LATE often-irreversible CES (Todd Br J Neurosurg 2017 PMID 28637110)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverecesi_urinary_difficulty_incomplete
    Incomplete CES — urinary hesitancy / loss of awareness of bladder filling without complete retention; bilateral sciatica + saddle paraesthesia present (BASS Germon Spine J 2015 PMID 25708139)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverephenotype_disc_herniation_ces
    Large central/paracentral lumbar disc herniation (typically L4-L5 or L5-S1) causing cauda equina compression — most common phenotype (BASS Germon Spine J 2015 PMID 25708139)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverephenotype_scan_negative_functional_ces
    Clinical features of CES (saddle change, urinary difficulty, bilateral sciatica) but MRI lumbosacral spine NEGATIVE for compression — scan-negative CES (Hoeritzauer Neurology 2020/21 PMID 33177221; Hoeritzauer J Neurol 2018 PMID 30298195)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseveretime_to_decompression_>48h_after_red_flag
    Time from onset of red-flag symptoms to surgical decompression exceeding 48 h (Quaile Int Orthop 2019 PMID 30374638)
    Trigger could not be auto-evaluated — needs clinician judgement.

Workflow calculators

This dossier does not reference any calculators.

Recommended regimen

CES adjunct bundle — catheterisation, analgesia, MESCC-overlay steroid, thromboprophylaxis, antiemetic (NICE NG59; BASS Germon Spine J 2015 PMID 25708139; Loblaw IJROBP 2012 PMID 22420969)
axis: ces_adjunct_bundlestep 1 - Step 1 — Catheterise for retention (urgent)
Selected step "Step 1 — Catheterise for retention (urgent)" — CESR (painless retention with overflow) or PVR >200 mL (BASS Germon 2015 PMID 25708139)
  • straight_then_indwelling_catheterisation
    first line
    procedure
    straight catheter for residual then 16-Fr indwelling pending decompression • urethral • continuous
    triggers: CESR, PVR_>200_mL
    Decompress overdistended bladder; document residual volume; preserve detrusor function (BASS Germon 2015 PMID 25708139)

ed playbook — drug actions (3)

  1. 1. morphine + ondansetron
    morphine 2-5 mg IV q5-10 min titrated; ondansetron 4-8 mg IV q8h • IV • PRN
    trigger: Severe acute back pain pre-op
    Short-course parenteral opioid bridge to surgery; antiemetic cover (NICE NG59)
  2. 2. dexamethasone (MESCC overlay ONLY)
    10 mg IV loading then 4-8 mg IV q6h • IV • q6h
    trigger: Known cancer + new CES + imaging-suspected MESCC
    Loblaw IJROBP 2012 PMID 22420969 — steroids recommended for MESCC with neurological deficit; bridge to RT or surgery
  3. 3. no NSAID
    — • — • —
    trigger: Neuraxial intervention anticipated
    Bleeding-risk if neuraxial procedure within hours (NICE NG59)

Auto-drafted A&P note

ed

Subjective

- Possible entry pathways: New bilateral leg pain / sciatica (NICE NG59 2016/2024; Todd Br J Neurosurg 2017 PMID 28637110); Perineal / saddle anaesthesia or paraesthesia (Lavy BMJ 2009 PMID 19336488; BASS Germon Spine J 2015 PMID 25708139); New urinary retention with overflow / bladder-emptying difficulty (BASS Germon 2015 PMID 25708139).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Cauda Equina Syndrome** (neuro.cauda-equina.v1).
Phenotype framing: Scan-positive phenotypes: disc-herniation-CES / spinal-stenosis acute decompensation / metastatic-MESCC / epidural haematoma / epidural abscess / trauma / iatrogenic; differentials: lumbar disc without CES (unilateral, no saddle/bladder), conus medullaris syndrome (UMN + LMN mix), spinal-cord infarct, transverse myelitis (separate dossier), scan-negative functional CES (Hoeritzauer 2018 PMID 30298195; Hoeritzauer 2020/21 PMID 33177221)
Scope: Adult with back pain + ≥1 red flag (bilateral sciatica / saddle change / urinary or bowel change / progressive deficit / new sexual dysfunction) — frame as time-critical surgical emergency until MRI excludes structural compression (NICE NG59; BASS Germon Spine J 2015 PMID 25708139)

No severity triggers fired against current inputs.

Plan

Regimen axis: **CES adjunct bundle — catheterisation, analgesia, MESCC-overlay steroid, thromboprophylaxis, antiemetic (NICE NG59; BASS Germon Spine J 2015 PMID 25708139; Loblaw IJROBP 2012 PMID 22420969)** — step "Step 1 — Catheterise for retention (urgent)".
1. straight_then_indwelling_catheterisation straight catheter for residual then 16-Fr indwelling pending decompression urethral continuous (procedure, first line) — Decompress overdistended bladder; document residual volume; preserve detrusor function (BASS Germon 2015 PMID 25708139)

Setting playbook (ed) — Recognise CES red flags within minutes of arrival; STAT lumbosacral MRI; same-day spinal-surgery consult; catheterise for retention; do NOT discharge unimaged on the basis of a clinical-rule alone (NICE NG59; BASS Germon Spine J 2015 PMID 25708139; Lavy BMJ 2009 PMID 19336488)
2. morphine + ondansetron morphine 2-5 mg IV q5-10 min titrated; ondansetron 4-8 mg IV q8h IV PRN — Severe acute back pain pre-op (Short-course parenteral opioid bridge to surgery; antiemetic cover (NICE NG59))
3. dexamethasone (MESCC overlay ONLY) 10 mg IV loading then 4-8 mg IV q6h IV q6h — Known cancer + new CES + imaging-suspected MESCC (Loblaw IJROBP 2012 PMID 22420969 — steroids recommended for MESCC with neurological deficit; bridge to RT or surgery)
4. no NSAID — — — — Neuraxial intervention anticipated (Bleeding-risk if neuraxial procedure within hours (NICE NG59))

Non-pharmacologic actions:
- STAT spinal surgical consult (orthopaedic spine or neurosurgery as locally configured)
- Catheterise for retention (straight then indwelling) and document residual
- NPO from time of MRI booking pending operative decision
- Two large-bore IVs; group & screen 2 units
- Document precise time-of-onset of red-flag symptoms (drives outcome — Srikandarajah Spine 2015 PMID 25646751)
- If MRI shows no compression → engage acute pain + functional-disorder pathway BEFORE discharge (Hoeritzauer Neurology 2020/21 PMID 33177221)
- If local MRI unavailable → same-day transfer to spinal centre (BASS Germon Spine J 2015 PMID 25708139)

AVOID / contraindication checks:
- No_NSAID_pre_neuraxial_intervention (NICE NG59)
- No_routine_steroid_for_non_neoplastic_CES (Loblaw IJROBP 2012 PMID 22420969 — steroid indication is MESCC specific, NOT compressive disc CES)
- No_gabapentinoid_for_CES_radicular_pain (PRECISE Mathieson NEJM 2017 PMID 28328324 — no benefit in sciatica)
- No_surgery_for_scan_negative_CES (Hoeritzauer Neurology 2020/21 PMID 33177221)
- LMWH_renal_adjust_if_CrCl_<30 (NICE NG89)
- Opioid_short_course_only_avoid_long_term_in_acute_LBP (NICE NG59; ACP 2017)

Monitoring

Regimen monitoring:
- hourly neuro obs first 24h post op (BASS Germon 2015 PMID 25708139)
- serial PVR post voiding trial (BASS Germon 2015 PMID 25708139)
- wound surveillance q shift (NICE NG59)
- opioid RR and sedation q1h when actively dosing (NICE NG59)
- serum glucose if dexamethasone for MESCC (Loblaw IJROBP 2012 PMID 22420969)

Setting (ed) monitoring:
- Neuro exam q30 min until MRI
- PVR repeat at 4 h if first PVR borderline
- Pain score q15 min during active opioid titration

Follow-up plan: Multidisciplinary rehab — urology (bladder retraining + ISC if persistent retention), colorectal (bowel programme), sexual health, physiotherapy, clinical psychology (post-CES distress + functional overlap), counselling on recurrence-from-stenosis prevention (NICE NG59; Quaile Int Orthop 2019 PMID 30374638)
- Close-out criterion: MDT rehab plan documented + outpatient spinal clinic + driving/return-to-work counselling

Monitoring phase: Post-op: hourly neuro obs × 24 h, voiding trial + serial PVR, bowel programme, wound surveillance, DVT prophylaxis. Scan-negative branch: pain + functional follow-up; serial neuro exam to detect late-developing compression (rare — Hoeritzauer 2020/21 PMID 33177221)

Disposition

Current setting: ed — Recognise CES red flags within minutes of arrival; STAT lumbosacral MRI; same-day spinal-surgery consult; catheterise for retention; do NOT discharge unimaged on the basis of a clinical-rule alone (NICE NG59; BASS Germon Spine J 2015 PMID 25708139; Lavy BMJ 2009 PMID 19336488)

Disposition criteria:
- MRI-confirmed compression → theatre / spinal centre transfer
- MRI-negative but high clinical suspicion → admit for serial neuro exam + acute pain + functional-disorder assessment (Hoeritzauer 2020/21 PMID 33177221)
- MRI-negative + low residual + improving symptoms → safe discharge with explicit return-precautions and spinal-clinic follow-up

Escalation triggers (move to higher acuity):
- Progressive motor deficit during workup → emergent OR notification (BASS Germon 2015 PMID 25708139)
- Inability to obtain MRI within 4 h locally → transfer initiation
- Confirmed MESCC → radiation oncology consult in addition to spinal surgery (Loblaw 2012 PMID 22420969)
- Suspected epidural abscess (fever + IVDU + back pain) → empiric IV antibiotics after blood + wound cultures; emergent surgical drainage

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Complete painless urinary retention (CESR) with overflow incontinence + PVR usually >500 mL (BASS Germon Spine J 2015 PMID 25708139)
- [LIFE_THREATENING] Bilateral lower-limb progressive motor weakness (≥1 MRC grade drop over hours) — surgical emergency irrespective of bladder status (Quaile Int Orthop 2019 PMID 30374638)
- [LIFE_THREATENING] Known active malignancy with new CES → metastatic epidural spinal cord compression overlay (Loblaw IJROBP 2012 PMID 22420969)

Citations

- NICE NG59 Low back pain and sciatica in over 16s (2016, updated 2024) + UK British Association of Spine Surgeons (BASS) Standards of Care for Cauda Equina Syndrome (Germon Spine J 2015) + Todd 2017 red/white flags systematic review [PMID:25708139](https://pubmed.ncbi.nlm.nih.gov/25708139/)
- Cited evidence (PMID 28637110) [PMID:28637110](https://pubmed.ncbi.nlm.nih.gov/28637110/)
- Cited evidence (PMID 33177221) [PMID:33177221](https://pubmed.ncbi.nlm.nih.gov/33177221/)
- Cited evidence (PMID 30298195) [PMID:30298195](https://pubmed.ncbi.nlm.nih.gov/30298195/)
- Cited evidence (PMID 25646751) [PMID:25646751](https://pubmed.ncbi.nlm.nih.gov/25646751/)

Last reconciled with current guidelines: 2026-05-26.
References
  • NICE NG59 Low back pain and sciatica in over 16s (2016, updated 2024) + UK British Association of Spine Surgeons (BASS) Standards of Care for Cauda Equina Syndrome (Germon Spine J 2015) + Todd 2017 red/white flags systematic review — PMID:25708139
  • Cited evidence (PMID 28637110) — PMID:28637110
  • Cited evidence (PMID 33177221) — PMID:33177221
  • Cited evidence (PMID 30298195) — PMID:30298195
  • Cited evidence (PMID 25646751) — PMID:25646751