Cauda Equina Syndrome

Cauda equina syndrome is a spinal condition in which the spinal nerves within the spinal canal become dangerously compressed. The common symptoms are listed in the chart.    

Notice how most of the symptoms are non-specific. Low back pain is present in most spinal conditions. Sciatica has many causes.    

Presuming a spinal cause, the emergence of bladder and bowel symptoms is a red flag symptom warranting emergent evaluation.    

Bladder symptoms from least to most severe involve:  

• Urgency to urinate  
• Straining to void 
• Retention — unable to void 
• Incontinence — voiding without control.  

In fact, the biggest danger of waiting for evaluation is functional loss might become irreversible.  

The feared complication of this syndrome, even more than pain, is permanent loss of bladder control.    

Bowel symptoms are less common than bladder symptoms. From least to most severe, they are:  

• Constipation  
• Loose rectal tone 
• Flaccid sensation of anus with wiping 
• Fecal staining of underwear from stool leakage 
• Incontinence — defecating without control 

Sexual dysfunction is another possible complication. In men, loss of function might be experienced as: 

• Altered or lost genital sensation  
• Inability to attain an erection  
• Inability to maintain an erection  
• Inability to achieve orgasm 

In women, loss of sexual function might be experienced as:  

• Altered or lost genital sensation  
• Inability to achieve orgasm 

 Cauda equina syndrome may occur from any cause that compresses the spinal canal and is observed in:  

• 2% of disc bulges  
• Grade 2 or higher spondylolisthesis  
• Severe spinal canal stenosis 
• Cancerous tumors  
• Hematomas — spinal bleeds after trauma or surgery  

The only effective treatment for cauda equina syndrome is emergency decompression surgery.    

From the time of symptom onset, patients have a 48-hour window to undergo surgery before the risks of permanent neurological injury. (Some studies indicate that 24-hours leads to better outcomes, when possible).  

The main outcome emergency decompression surgery attempts to reverse is the prevention of complete cauda equina syndrome in which permanent incontinence of the bladder or bowel emerges.   

Despite the risks, CES is misdiagnosed and overlooked. This results in poor clinical outcomes for patients and, for the clinician who missed the diagnosis, risks of legal action for medical malpractice.    

The diagnosis of cauda equina syndrome is not always straight-forward for the following reasons:  

1. A lack of clinical familiarity with this rare condition 
2. The MRI may not explicitly state that there is cauda equina syndrome 
3. The available MRI may not be up-to-date  
4. Bladder and bowel symptoms might be vague and mild at first 

The simple aspect of diagnosis of cauda equina syndrome is an up-to-date MRI can just about always exclude this condition. The reason: an extensive blockage of the spinal canal causes almost all cases and is therefore hard-to-miss.  

Select References  

Fast, Avital, and Dorith Goldsher. Navigating the adult spine: bridging clinical practice and neuroradiology. Demos Medical Publishing, 2006.   

Fraser, Stuart, Lisa Roberts, and Eve Murphy. “Cauda equina syndrome: a literature review of its definition and clinical presentation.” Archives of physical medicine and rehabilitation 90.11 (2009): 1964-1968.   

Gitelman, Alex, et al. “Cauda equina syndrome: a comprehensive review.” Am J Orthop (Belle Mead NJ) 37.11 (2008): 556-62.   

Lavy, Chris, et al. “Cauda equina syndrome.” Bmj 338 (2009).