Cauda Equina Syndrome: Recognising a Spinal Emergency
How to screen for cauda equina syndrome at the pharmacy counter and refer appropriately when back pain or sciatica is accompanied by bladder, bowel, or saddle sensation changes.
Why this matters
Cauda equina syndrome (CES) is a rare but devastating spinal emergency caused by compression of the nerve roots at the base of the spinal cord. It affects 1 to 3 people per 100,000 population each year, most commonly due to a large lumbar disc prolapse, though tumour, haematoma, spinal infection, and trauma are also recognised causes.1,3 If compression is not relieved promptly, patients can suffer permanent loss of bladder and bowel control, sexual dysfunction, and bilateral lower limb weakness, neurological deficit, and permanent disability.5
Community pharmacists are well placed to identify patients who may be developing CES. A patient buying analgesics for sciatica who mentions difficulty passing urine, or numbness in the saddle area, should never leave without an urgent assessment. Early recognition and immediate referral can be the difference between full recovery and permanent disability. The condition does not follow a single clinical pattern: no one symptom is diagnostic on its own, and negative physical tests do not rule out CES if positive subjective symptoms are present.1,4
Red flags vs more likely benign
| Feature | More likely benign | Red flag ⚠ |
|---|---|---|
| Bladder function | Able to void normally with full sensation | Difficulty starting, reduced stream, impaired sensation of flow, or inability to void at all |
| Saddle area sensation | Normal feeling in perineum, inner thighs, genitals, and buttocks | Numbness, pins and needles, or reduced sensation in the saddle area (S2 to S5 dermatomes) |
| Bowel control | Normal bowel control and rectal sensation | Reduced sensation of rectal fullness, or loss of bowel control |
| Leg symptoms | Unilateral sciatica or back pain, stable | Severe or progressive neurological deficit of both legs, such as new major weakness affecting walking, foot lift, knee extension, or ankle movement. Note: bilateral sciatica or leg pain without bladder, bowel, saddle, or sexual symptoms is urgent MSK triage, not a CES emergency. |
| Sexual function | No change | New loss of genital sensation, or new inability to achieve erection, ejaculate, or orgasm |
| Symptom course | Longstanding, gradual, or stable symptoms | Rapid onset or deteriorating neurological symptoms within the last 14 days |
Questions to ask any patient with back pain or sciatica
A brief targeted screen for CES symptoms takes under two minutes and can identify a spinal emergency. Patients rarely volunteer bladder, bowel, or saddle symptoms without direct questioning: always ask.
- "Are you having any trouble passing urine? Do you have to strain, or does it take a while to get started? Does the flow feel weaker than normal?"
- "Have you had any leaking of urine that you could not control, or any accidents?"
- "Have you noticed any numbness or tingling in your inner thighs, between your legs, around your genitals, or around your back passage?"
- "Any change in your bowel control, or do you feel less sensation when you need to go?"
- "Has the pain or weakness spread to both legs, or are you getting new weakness in either leg?"
Urinary incontinence alone is less specific for CES, but it should still prompt a full CES screen. Consider urinary tract infection, stress incontinence, and urge incontinence as alternative causes, but only exclude CES if saddle area sensation, urinary sensation, bowel, sexual, and neurological function are all normal.1 Digital rectal examination is not required in community pharmacy triage, but subjective perianal and saddle sensation should be asked about and documented.1 Negative physical tests do not rule out CES if positive subjective symptoms are present.1,4
Documenting a CES consultation
GIRFT recommends pharmacists document the following whenever CES is suspected or cannot be excluded:
- Exact symptoms reported and their onset or deterioration date
- Urinary symptoms: stream quality, sensation of flow, any retention or incontinence
- Saddle area sensation: presence or absence of numbness, tingling, or perianal changes
- Who was contacted (999, NHS 111, GP, or Emergency Department) and the advice given
Thorough documentation protects the patient and the pharmacist if the referral pathway is later reviewed.
What to do in pharmacy
Key takeaways
- Any CES symptom of recent onset alongside back or leg pain requires immediate referral to the nearest Emergency Department: do not delay for a GP appointment.
- Always ask directly about bladder stream, saddle sensation, and bowel control: patients rarely raise these symptoms unprompted, and negative physical tests do not rule out CES.
- Urinary incontinence alone is less specific for CES, but must still prompt a full CES screen: only exclude CES if saddle sensation, urinary sensation, bowel, sexual, and neurological function are all normal.
📚 References
- NHS England, Getting It Right First Time. National Suspected Cauda Equina Syndrome (CES) Pathway. NHS England; 2023 (updated March 2026). Available from: https://gettingitrightfirsttime.co.uk/wp-content/uploads/2026/04/National-Suspected-Cauda-Equina-Pathway-March-2026.pdf
- National Institute for Health and Care Excellence. Low back pain and sciatica in over 16s: assessment and management. NICE guideline NG59. NICE; 2016 (updated December 2020). Available from: https://www.nice.org.uk/guidance/ng59
- Greenhalgh S, Finucane L, Mercer C, Selfe J. Assessment and management of cauda equina syndrome. Musculoskelet Sci Pract. 2018;37:69-74.
- Todd NV. Guidelines for cauda equina syndrome. Red flags and white flags. Systematic review and implications for triage. Br J Neurosurg. 2017;31(3):336-9.
- Woodfield J, et al. Presentation, management, and outcomes of cauda equina syndrome up to one year after surgery: a multi-centre prospective cohort study. Lancet Reg Health Eur. 2023;24:100545.