Cauda Equina Syndrome Basics


Cauda Equina Syndrome Definition


Cauda Equina Syndrome- is collection of symptoms due to a spinal nerve root disorder caused by injury to the cauda equina located in the spinal canal of the lumbar and sacral spine. The cauda equina transmits signals to and from the spinal cord (part of the central nervous system); relaying signals to and from the lower extremities, genitalia, lower abdomen, bladder, and rectal sphincters back to the spinal cord.


The cauda equina is currently classified as part of the peripheral nervous system as it is made up of lower motor neurons and the spinal cord and brain are made up of upper motor neurons. This is the reason Cauda Equina Syndrome is NOT a spinal cord injury, even though it resides within the spinal canal, the meninges, and cerebral spinal fluid.


Cauda Equina Syndrome Stages


There are three stages of Cauda Equina Syndrome; Acute, Potential Recovery Stage, and Chronic Cauda Equina Syndrome. (Potential Recovery Stage is not a currently recognized stage of Cauda Equina Syndrome by medical literature, however, there is no name for the phase between initial diagnosis/acute and chronic Cauda Equina Syndrome.)


Acute Cauda Equina Syndrome- A series of symptoms that arise from acute injury of the cauda equina. This means that the injury has just happened or is currently happening. This stage requires immediate evaluation by emergency medical teams. If you think you have Red Flag Symptoms of Cauda Equina Syndrome, seek emergency evaluation at the nearest emergency room. With timely treatment, Acute Cauda Equina Symptoms can be reversed or worsening can be stopped. Treatment MUST occur in the first 48 hours from ONSET of symptoms for the best patient outcomes. It is important to note that not all causes of Cauda Equina Syndrome have a treatment at this time. 


Acute Cauda Equina Syndrome Symptoms

Symptoms of Acute Cauda Equina Syndrome Include:

  • bladder and/or bowel dysfunction (incontinence is a late sign and has the poorest prognosis)

  • paresthesia and/or anesthesia of the lower extremities, lower abdomen, perineum, and/or genitalia

  • sciatica, usually bilateral, but not always

  • severe lower back pain

  • lower extremity weakness

  • abnormal and/or absent reflexes

  • foot drop

  • hip drop

  • gait disturbances and/or inability to walk

  • abnormal proprioception

  • sexual dysfunction

Patients do not have to have all of these symptoms to be diagnosed with Cauda Equina Syndrome. Nor do the symptoms need to be bilateral, although that is the most common. Note that one side is usually affected more than the other, but not in all cases. Additionally, not all patients realize they have paresthesia until a health care provider touches them.

The most common reason for the misdiagnosis of Cauda Equina Syndrome is failure to consider the diagnosis and misinformation of the disease. For example, some practitioners are under the false assumption that a patient must have incontinence and/or saddle anesthesia to have CES. THIS IS WRONG. While highly likely that there is bladder and/or bowel involvement and some loss of sensory and motor function in A-CES, there are cases where individuals do not have any saddle anesthesia and/or bladder/bowel involvement. This is why MRI, or other imaging, is so important in the emergency setting if a patient has multiple RED Flag Symptoms; the gold standard being MRI. Click here to learn more about the symptoms of Acute Cauda Equina Syndrome. 


Causes of Acute Cauda Equina Syndrome include: 

  • disk herniation (most common)

  • tumor

  • spinal stroke

  • blood clot

  • infections (including Tuberculosis)

  • meningitis 

  • traumas

  • lumbar surgery

  • epidural steroid injections (esi)

  • epidurals

  • childbirth

  • shearing (sudden stretching of the cauda equina)

  • tethered cord

  • hematomas

  • neuroinflammation

  • accidental injury during lumbar procedures 

  • Arachnoiditis

  • Adhesive Arachnoiditis

  • broken vertebrae

  • other unknown causes (given the limited amount of CES research, this list is still growing)

  • Cancer

  • Chemotherapy

  • Radiation


Potential Recovery Stage Cauda Equina Syndrome (PRS CES)- The stage between initial CES treatment and expected recovery time. This is not a recognized stage of CES, nor classification. But this time period does not have a name in literature. This timeframe is the greatest chance of recovery of function and reversal of deficits, and physical & pelvic floor physical therapy show the most obvious benefits. Though they remain beneficial throughout the patient's diagnosis, improvements are just not as obvious and take much longer. (This is not an official stage recognized by medical literature, but is a gray area without a name.)


Chronic Cauda Equina Syndrome (Ch-CES)- A patient that has been diagnosed with CES and has not made a full recovery in the expected recovery time individual to the patient (3-24 months). The neurologist and/or neurosurgeon can better determine the expected recovery time. Individuals with Ch-CES will likely have the symptoms they are experiencing at 12 months for the rest of their lives with periods of flare-ups. We do not understand the underlying mechanisms of flareups in Ch-CES. These individuals can make small and slow recoveries over many years with proper therapy and treatments, so never give up hope and never give up treatment. Exercise, particularly aquatic exercises, yoga, and recumbent bicycling are extremely good exercises to get into. 


Chronic Cauda Equina Syndrome Symptoms

Common anecdotal patient-reported symptoms of Chronic CES and increased risks of other co-morbidities including but not limited to:


  • Chronic and Chronic Intractable Pain

  • Electric Shocks

  • Facial Flushing

  • Severe Sweating Episodes

  • Deconditioning

  • Autoimmune Disorders

  • Multiple Rare Diseases

  • Adrenal Insufficiency both Opioid-Induced and non-Opioid-Induced

  • B vitamin mal-absorption

  • Tremors

  • Flare-ups of possible neuroinflammation causing increase in symptoms

  • Chronic Pain/Intractable Pain

  • Lower Extremity Swelling and Poor Circulation (slowed healing of wounds)

  • Poor Temperature Regulation of the Lower Extremities

  • Falls and increased risks of fall-related injuries, subsequent hospital admissions, and subsequent surgeries to repair fall-related injuries

  • Mental Health Disorders including Depression, Anxiety, and PTSD

  • Musculoskeletal Pain and injuries from Compensatory Gait Imbalances

  • Higher risks of osteoporosis from medication side effects and lack of mobility, exercise, and weight-bearing

  • Obesity and subsequent co-morbidities,

  • Higher risks of blood clots and associated risks, pulmonary embolism, pneumonia, severe COVID-19 illness, and stroke

  • Higher risks of heart disease

  • Higher risks of diabetes

  • Changes in bone structure due to joint instability

  • Shoulder disorders due to assistive walking devices and wheelchair use

  • Increased risks of pressure sores and associated infections

  • Chronic Urinary Tract Infections

  • Chronic Constipation

  • General Malaise (flu-like symptoms)

  • Restless Back Syndrome (Exactly like Restless Leg Syndrome except in the Back and not associated with Secondary Restless Leg Syndrome)

  • Pseudodementia “Brain Fog”

  • Severe Fatigue

  • Sciatica (usually bilateral)

  • Radiculopathy

  • Neuropathy

  • Social Economical Devastation (due to decreased ability to work or complete inability to work)

  • Facet Arthropathy

  • Facet Hypertrophy

  • Spinal Instability

  • Failed Back Surgery Syndrome

  • Arachnoiditis/Adhesive Arachnoiditis

  • Bladder Dysfunction

  • Bowel dysfunction

  • Paresthesia and/or anesthesia of the lower extremities and genitalia

  • *Severe Lower Back Pain

  • Lower extremity weakness

  • Abnormal or absent reflexes

  • Foot drop (can be unilateral or bilateral)

  • Hip drop

  • Gait Disturbances

  • Abnormal Proprioception

  • Sexual Dysfunction

  • Spasticity (Food for thought. CES is a peripheral nervous system injury, spasticity should not be possible, other than in the bladder. We know the cauda equina is not a central nervous system disorder, and therefore not a spinal cord injury because the cauda equina is made up of lower motor neurons. Does this mean that the cauda equina has its own characteristics different from peripheral nerves outside of the spinal column? We don’t know, research is needed.)



Not every Chronic Cauda Equina Syndrome patient has every symptom listed, however, this is a list of the most common symptoms reported by our members. Many have one side worse than the other but usually have bilateral symptoms. Rarely will only one side be affected, but it is reported. We were involved in a Delphi Study Consensus meeting to determine the most important patient outcomes for those with Cauda Equina Syndrome, termed Core Outcome Set of Cauda Equina Syndrome (COSCES). 



Cauda Equina Syndrome Severity Classifications


In addition to  Acute, PRS, and Chronic Cauda Equina Syndrome, there are classifications of severity of Cauda Equina Syndrome, currently in literature Incomplete Cauda Equina Syndrome (CES-I) and Complete Cauda Equina Syndrome (CES-C). Some literature, particularly outside of the United States, classify CES-C as CES-R or retention, for the purpose of our education we will use CES-R for High-Risk Cauda Euqina Syndrome.


High-Risk Cauda Equina Syndrome 


High-Risk Cauda Equina Syndrome, CES-R, is a classification for individuals showing mild RED Flag Symptoms of Cauda Equina Syndrome but do not have evidence of emergent need for surgery or treatment on imaging, nor are they officially diagnosed with Cauda Equina Syndrome. These patient require close monitoring, education, and a treatment plan.


CES-R patients may have more conservative treatments including physical therapy, pain management, inflammation treatment, and very close monitoring. When the cause of CES-R is a mechanical reason, something that can be fixed surgically, some physicians will choose to proceed with surgical repair to prevent Cauda Equina Syndrome.  It is important to note that individuals that have CES-R can transition to Incomplete or Complete Cauda Equina Syndrome at any moment, depending on what is causing the symptoms. There have been patient reported cases of transitioning from CES-R to CES-I from sneezing, vacuuming, tripping, falling, and "waking up with it". Patient education is extremely important for patients that are on a conservative treatment plan, particularly when to return to the emergency department and activities to avoid.




23-hour observation, neurosurgery consult, pain management, fall precautions, spinal precautions, blood clot prevention, patient education, pressure sore prevention (remember these patients might have decreased mobility and sensation). The neurosurgeon will make further recommendations and more in-depth treatment plan. 


The definition of CES-I, in literature, is Cauda Equina Syndrome in which an individual is NOT incontinent. These individuals may or may not have bladder dysfunction, urinary retention, urinary leakage, and trouble initiating and maintaining flow, they may even need to catheterize at times, and have chronic urinary tract infections, however, they are NOT incontinent. Unfortunately, this same individual can have every other issue listed above in the Chronic CES list but because they are not incontinent they are not considered complete for severity scoring.


Complete CES is defined as individuals with CES that have incontinence. These individuals may also have every symptoms off of the Chronic CES list, however, even when they only have incontinence (as horrible as that is) they are not as severe as someone with CES-I that also has many symptoms on the Chronic CES list of symptoms. For this reason, Cauda Equina Foundation is working to develop a better scoring system. In some countries, the CES-I or CES-C classification determines eligibility for services and assistance and with the current scoring system, this is a major disservice to those individuals with catastrophic CES that are still considered incomplete.


Perhaps additional scoring will include catastrophic CES in which individuals that have “x” number of devastating symptoms are classified? Only research will tell.