Cauda Equina Syndrome (CES)
Questionnaire/history:
How have symptoms changed and over what time?
Have things worsened over days or weeks?
(Note: established urinary or bowel symptoms that have been stable for more than 4 weeks are unlikely to be treated with emergency surgery)
Any changes in sensation?
"Sciatica" with pain or altered sensation in the lower legs below the knee, ie L4, L5, S1 distributions?
(Note: New unilateral sciatica with other CES features or new sudden bilateral sciatica should prompt referral (though 60% did not have it), bilateral sciatica is commonly listed as a "red flag" but may be present in many older people without CES as a feature of degenerative spinal stenosis, if stable and no neurology then treat as radicular pain, if dermatomal or myotomal loss which is worsening then for urgent referral and if any features of CES including sudden changes in myotomal or dermatomal loss then for same-day referral)
Change or loss of sensation?
Altered sensation on washing and wiping in the saddle, perianal, perineal or genital area (should prompt emergency referral)?
Can tell when bladder is full or empty?
Can sense micturition?
Can you tell when bladder is full or empty?
Can you sense micturition?
Can you tell if rectum is full?
Changes in leg power?
Knee extension?
Ankle eversion?
Foot dorsiflexion?
(Note: Suspect CES if severe progressive neurological deficit of both legs (31%))
Changes in autonomic function?
Increasing difficulty when trying to urinate or difficulty stopping urine stream?
Unconscious voiding?
Inability to void?
Difficulty in initiation of voiding due to being in pain (this will have normal urogenital sensation?
Drugs for back pain causing anticholinergic side effects and reducing bladder emptying (eg opioids, amitriptyline (Have these been added to other anticholinergics, especially overactive bladder medications?)?
Bowel incontinence (usually a late sign of CES-R and lots of other causes)?
Loss of sensation during intercourse/masturbation or new erectile dysfunction/inability to ejaculate?
Past medical History:
Current medication?
Known drug allergies?
Examination:
Lower limb neurological exam:
Weakness (MRC power grading)?
Hip?
Flexion (L1/2) ('Raise your leg off the bed and stop me from pushing it down.")?
Extension (L5/S1) ('Stop me from lifting your leg off the bed.')?
Abduction (L4/5) ('Push your legs out')?
Adduction (L2/3) ('Squeeze your legs in')?
Knee?
Flexion (S1) ('Bend your knee and stop me from straightening it.')?
Extension (L3/4) ('Kick out you leg'.)?
Ankle?
Dorsiflexion (L4) ('Keep your legs flat on the bed ... cock your foot up towards your face ... don't let me push it down.')?
Plantarflexion (S1/2) ('Push down like on a pedal'.)?
Eversion (L5/S1) ('Push your foot out against my hand.')?
Big toe?
Extension (L5) ('Don't leg me push your big toe down.')?
Loss of or reduced light touch and/or pin prick sensation in a dermatomal distribution?
L1 - Midway between the key sensory points for T12 and L2?
L2 - On the anterior medial thigh, at the midpoint of a line connecting the midpoint of the inguinal ligament and the medial epicondyle of the femur?
L3 - At the medial epicondyle of the femur?
L4 - Over the medial malleolus?
L5 - On the dorsum of the foot at the third metatarsophalangeal joint?
S1 - On the lateral aspect of the calcaneus?
S2 - At the midpoint of the popliteal fossa?
Perineal sensation?
(Note: If objectively deficient then be concerned but if the patient reports loss but is objectively intact act on the safe side and do not be reassured)
Reduced reflexes?
Patellar reflex (L3/4)?
Achilles reflex (L5/S1)?
(Note: Absent Achilles reflex strongest objective clinical indicator of CES, but only 15% of CES +ve had this, and 64% of CES +ve had normal reflexes)
Plantar reflex?
Babinski sign (UMN lesion)?
Rectal examination does not need to be performed
Diagnosis:
Early / suspected CES (concerning change in symptoms such as a sudden progression from unilateral sciatica to bilateral or early sensory changes in the genitals or perineum eg one side of the vulva develops anaesthesia or paresthesia)
CES-I for Incomplete (with reduced urinary sensation, loss of desire to void or poor stream but no established retention or overflow)
CES-R for frank retention (usually painless with or without overflow incontinence)?
(Note: CES most often caused by a central lumbar disc prolapse, associated with sciatica as often compression of a lateral, exiting, nerve root due to a prolapsed disc before this disc migrates centrally and compresses the central nerve roots that are yet to exit
It is a lower motor nerve lesion as it compresses roots, not the cord
Autonomic nerves supplying the bladder, sexual organs and the bowel are narrow and susceptible to damage by compression which is irreversible if not decompressed, usually by emergency surgery
Management:
Emergency imaging (MRI) and emergency surgery if confirmed CES
Advised:
Same-day clinical review as soon as possible if perineal/perianal tingling or numbness (eg when washing or wiping) or any disturbance of normal urinary or sexual function, particularly if bilateral sciatica
Resource(s):
BOA/BSR/RCGP emergency MSK conditions 2020
UKSSB National back pain pathway 2020
Information for patient/carer(s):