Cauda equina syndrome (CES) is a medical emergency and occurs when a patient suffers compression to the spinal nerve roots inside the dura, beyond the termination of the spinal cord. This is most commonly as a result of a prolapsed intervertebral disc, although rarely it can also be caused through infection or tumour.

A failure to quickly refer or treat a patient presenting with signs of CES can have serious consequences, including paralysis, incontinence and impaired mobility. Unfortunately, lower back pain is a very common complaint and at its earliest stages a diagnosis of CES can be difficult to diagnose.

Consequently, and despite CES being a rare event, it is not uncommon to see claims for clinical negligence in relation to this syndrome due to the significant impact it can have on a patient's lifestyle. The critical point is that a referral needs to be made in time to allow surgical treatment before the syndrome is complete. This is essential to give the patient a chance of salvaging useful function.

Why can CES claims be expensive?

For a claim to be successful the claimant has to show that the care provided by the doctor fell below a reasonable standard; that is, that there has been a 'breach of duty'. The claimant must then show that the breach has caused loss or damage, which is termed 'causation'. Both claimants and defendants will instruct independent experts to investigate these two aspects of a claim.

CES claims can be made for a large amount of money. The degree of damage that resulted from the breach of duty will often only be a fraction of the claim, with the care costs and consequential losses forming the bulk of the overall value of the case.

For example, if, as a result of a delay in referral, the patient has suffered a complete loss of bladder and bowel function, an award of around £130,000 can be given for that injury alone. On top of this the patient is entitled to claim compensation for any care, aids and equipment required, and their 'loss of earnings if they are no longer able to continue working.

If the patient was a high earner and still had many years of employment ahead of them, this can equate to a very large payment in compensation as the aim is to put the patient back in the position they would have been 'but for' the negligence.

If, however, the patient has made a good recovery with very limited sequelae, then the claim may only be worth a small amount to reflect a period of pain or suffering. If the independent expert evidence indicates that the same level of injury would have occurred in any event, there may be no compensation awarded or the compensation will be very small. This might be the case if the delay was only a matter of hours, or if the injury was already established at the time the patient saw the doctor.

Analysis

The MDU undertook an analysis of CES claims that were closed between January 2005 and August 2016. During that period nearly 150 claims were notified to the MDU, with 92% of these brought against GPs. The MDU successfully defended over 70% of the claims notified in this period, including one claim which was won at trial. In order to defend these cases, the MDU spent nearly £350,000 on legal costs.

Of the cases that were settled, over £8 million in compensation was paid out by the MDU. Damages payments ranged from £2,250 to £670,000, and of the cases settled, 12% attracted damages payments of over £500,000. However, the large majority of cases settled by the MDU have had compensation agreements of under £100,000.

The MDU also paid over £4.5 million with respect to claimant solicitors' costs. Only one of the cases settled related to a claim against a private hospital doctor, and this related to a failure to consent a patient for the risk of CES, which she eventually suffered, prior to spinal surgery.

Out-of-hours GPs

When analysing the GP claims made in relation to an alleged delayed diagnosis of CES, 10% related to an out-of-hours consultation or telephone call. Of these out-of-hours claims, a third were settled, which perhaps illustrates the difficulty of assessing this condition in an out-of-hours setting.

Red flags

The following indicators should be considered 'red flag' symptoms that should raise suspicion of CES in a patient with back pain.

• Pain that radiates below the knees bilaterally (on rare occasions this can be unilateral).
• Bilateral lower limb numbness or weakness.
• Numbness either side of the buttocks and saddle area.
• Bladder and/or bowel disturbance (including difficulty passing urine, poor stream, loss of sensation).
• Erectile dysfunction.
• Loss of anal tone or impaired sensation on per rectal (PR) examination.

MDU top tips

• Conduct a full examination to establish the likely cause of the back pain and make a record that this has been done.
• Consider whether there are any red flags.
  
• If red flags are present, the patient needs to be seen in hospital urgently. Call the orthopaedic or neurosurgical specialist for immediate advice, or if this is not available, arrange for the patient to be admitted to hospital via the emergency department.
• If no red flags are present, make a record in the notes to demonstrate you have actively considered the condition.
  
• If, after the assessment, the patient is being managed as having simple mechanical back pain, make sure you give appropriate safety netting advice. This should include advising the patient of the red flag symptoms and the importance of seeking urgent medical attention if these appear. Again, try to make a record in the notes of the specific safety netting advice that has been given.