Back pain is common, Cauda Equina Syndrome (CES) is rare. Its consequences can be extremely serious and it features disproportionately in litigation. What are the signs and symptoms of which a GP or other medical professional needs to be aware to identify possible CES and to distinguish it from common back pain.
What is CES?
The cauda equina or "horse's tail" is a matrix of nerves which fall below the conus medularis at the base of the spinal cord. CES is a syndrome which has a number of stages:
CES-S - suspected CES typically severe back pain with bilateral neurogenic symptoms such as leg pain or weakness. Mechanical or referred leg pain is not neurogenic. A record of "sciatica" may not be evidence of CES-S, but may be a mis-description of neurogenic pain.
CES-I - incomplete CES, typically severe back pain with altered urinary sensation for example loss of desire to void, diminshed sensation, poor stream and need to strain. There may be painful retention of urine. There may also be saddles anaesthesia and sphincter disturbance.
CES-R - CES as above but with painless retention of urine.
CES-C - Complete CES often with no urinary or bowel function and with sexual dysfunction.
Progression can be very rapid but may follow an acute onset or chronic back pain.
CES is caused by compression on the CE and may be due to malignancy, an abscess or a haematoma, but the most common cause is a central disc prolapse usually at L4/L5 or L5/S1.
So-called Red Flags for CES are urinary dysfunction, bowel dysfunction, bilateral neurogenic symptoms, saddle anaesthesia and sexual dysfunction. GPs need to be alert to the possibility of CES. Patients may not volunteer relevant information. For example a patient may have noticed a slight loss of feeling when wiping herself with toilet paper. She might not associate that with her back pain and therefore not report it. On proper questioning a GP might well elicit that symptom and heed the relevance of it.
Courtesy of the CES Association
Thus, the Court will be greatly assisted by evidence of what symptoms a patient had and when, what questions were asked by a GP, what answers were given and what examination he/she performed. Digitial Rectal Examination may elicit a red flag sign of a patulous anus, but a GP is not expected to reach for the gloves every time a patient comes into the surgery complaining of a bad back.
Unfortunately there is no one definitive statement of the Red Flag signs and symptoms. Various statements of them have been given by NICE, by the CES Association, by the European Guidelines for the Management of Acute Non-Specific Low Back Pain in Primary Care and by the RCGP.
In terms of causation, referral should be for specialist investigation which will include an MRI scan. X-rays are not helpful. Referral should be urgent, even as an emergency. Treatment is by way of surgical decompression. once a patient has CES-C, and arguably once they have CES-R it is probably too late for surgery to make a difference to outcome. Therefore if actual referral is made at that stage, the time from referral to surgery should not necessarily be taken as an indication of the likely time between referral and surgery if referral had been made at an earlier stage.
Classically, litigation arises when the patient first presented with CES-S or CES-I which then progressed to CES-R or CES-C before surgery was performed. If progression was very rapid, then proving causation may be very difficult. It is thought that surgery when a patient is at an earlier stage of CES will prevent progression to a later, more injurious stage.
Patients left with CES-I are likely to be able to function socially and at work. They may be more aware of where toilets are located, and they may make preparations before they leave the home etc. but they will be able to function. Patients with CES-R or CES-C may well not be able to work. They may need assistance at home.
Useful case law includes:
McEleney-v-Kamal Ohri et al  CSOH 2003
Oakes-v-Neininger  EWHC 548 (QB)
Zarb-v-Odetoyinko  2880
Hussain-v-Bradford Teaching Hospital NHS Foundation Trust  EWHC 2914 (QB)