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NICE Guideline changes to red flag symptoms for diagnosing cauda equina syndrome

Arti Shah

Healthcare professionals use guidelines called "Clinical Knowledge Summaries" (CKS) for diagnosing a serious condition called cauda equina syndrome (CES). The National Institute of Health and Care Excellence (NICE), working with the Medical Protection Society (MPS) has recently made changes to these CKS guidelines in an effort to lead to an earlier diagnosis, and hopefully reduce the number of patients who are left with permanent nerve damage as a result of being affected.

What is cauda equina syndrome – condition and symptoms

There are a group of nerves in the back, at the lower end of the spine, which are known as the cauda equina (from the Latin name for "horse's tail", which they resemble). These nerves control the bladder and bowel, movement of the legs, and also sense (light) touch and pain in the legs and around the back passage area. 

Cauda equina syndrome is a serious condition where a narrowing of the spinal canal causes these nerves to become compressed, leading to problems which include:

  • Numbness and weakness in one or both legs
  • Deterioration or loss of bowel and/or bladder control
  • Numbness of the saddle area around the back passage


The most common cause of CES is a prolapsed disc, although there are others. It occurs mostly in adults.

Thankfully, it is a rare condition, however, it is classified as a medical emergency, and requires urgent treatment to prevent permanent nerve damage.

Diagnosis and treatment

The signs and symptoms referred to above are known as "red flag" symptoms, as their existence suggests a potentially serious condition which requires swift treatment.

A comprehensive examination should take place, including taking a thorough history and performing a clinical examination. If suspected, urgent neurosurgical referral should be made, and an MRI scan should be performed to exclude the diagnosis.

Urgent spinal decompression surgery is the most common treatment. Further follow up tests and investigations may need to be performed post-surgery. 


A failure to treat cauda equina syndrome in a timely period can lead to permanent nerve damage, including:

  • Loss of bladder and/or bowel control
  • Loss of sexual function
  • Permanent paralysis
  • Sensory abnormalities

It is recognised that the later the diagnosis and longer the delay, the increase in the risk of there being a permanent neurological deficit, with a range in severity.

The new guidelines

With the above in mind, NICE have included new, more explicit symptoms for practitioners to look out for, and aid delays in diagnosis. These include:

  • Bilateral sciatica
  • Severe or progressive bilateral neurological deficit of the legs, such as major motor weakness with knee extension, ankle eversion, or foot dorsiflexion
  • Difficulty initiating micturition or impaired sensation of urinary flow, if untreated, this may lead to irreversible urinary retention with overflow urinary incontinence
  • Loss of sensation of rectal fullness, if untreated this may lead to irreversible faecal incontinence
  • Perianal, perineal or genital sensory loss (saddle anaesthesia or paraesthesia)
  • Laxity of the anal sphincter

These recommendations are welcomed to highlight early detection and treatment, and ultimately, to safeguard patients.

We often see cases where the classic signs listed above are ignored or identified at late stages, resulting in irreversible damage and subsequent disability, affecting almost every aspect of a patient's activities of daily living, and their quality of life. The consequences are extremely severe, and so a higher index of suspicion will hopefully limit future cases of delayed diagnosis.

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