eMedicine Specialties > Emergency Medicine > Neurology

Cauda Equina Syndrome

Michael S Beeson, MD, MBA, FACEP, Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine; Program Director, Emergency Medicine Residency, Summa Health System

Updated: Jun 17, 2009

Introduction

Background

The cauda equina (CE) is formed by nerve roots caudal to the level of spinal cord termination. Cauda equina syndrome (CES) has been defined as low back pain, unilateral or usually bilateral sciatica, saddle sensory disturbances, bladder and bowel dysfunction, and variable lower extremity motor and sensory loss usually due to mechanical compression of the cauda. Though the lesion is technically to nerve roots and represents a "peripheral" nerve injury, damage may be irreversible and CES may be a surgical emergency.¹

Lesions involving the termination of the spinal cord (conus medullaris) are not discussed in this article. Please refer to Spinal Cord Injuries.

Pathophysiology

Cauda equina syndrome may result from any lesion that compresses CE nerve roots. These nerve roots are particularly susceptible to injury, since they have a poorly developed epineurium. When well developed, as in peripheral nerves, they protect against compressive and tensile stresses. The microvascular systems of nerve roots have a region of relative hypovascularity in their proximal third. Increased vascular permeability and subsequent diffusion from the surrounding cerebral spinal fluid supplement the nutritional supply. This property of increased permeability may be related to the tendency toward edema formation of the nerve roots, which may result in edema compounding initial and sometimes seemingly slight injury.

Frequency

United States

Cauda equina syndrome is uncommon, both atraumatically as well as traumatically. It is often reported as a case report due to its rare presentation. Although infrequent, it is a diagnosis that must be considered in patients who complain of low back pain coupled with neurologic complaints, especially urinary symptoms.

Mortality/Morbidity

Cauda equina syndrome is not fatal.

Morbidity is variable, depending on the etiology of the syndrome. Morbidity is associated with the long-term sequelae of the effects of cauda equina syndrome, such as bladder dysfunction, loss of control of bowel or bladder, associated leg weakness, decubitus ulcers, or venous thromboemboli.

Race

No predilection exists on the basis of race.

Sex

No predilection exists on the basis of gender.

Age

Traumatic cauda equina syndrome is not age specific. Atraumatic cauda equina syndrome occurs primarily in adults as a result of surgical morbidity, spinal disk disease, metastatic cancer, or epidural abscess.

Epidural abscess with effacement of thecal sac in a 56-year-old man.

Clinical

History

A patient with cauda equina syndrome (CES) often presents with nonspecific symptoms, with back pain the most significant and dramatic. Occasionally, history of incontinence of urine or stool, or occasionally saddle paresthesias, is volunteered. If not volunteered, this history should be elicited from anyone complaining of low back pain. Bell et al demonstrated that there is diagnostic accuracy of urinary retention, urinary frequency, urinary incontinence, altered urinary sensation, and altered perineal sensation with MRI findings demonstrating disk prolapse.^2,3 Specific historical points to elicit from the patient include the following:

Low back pain - This pain may have some characteristic that suggests something different from the far more common lumbar strain. Patients may report severity or a trigger, such as head turning, that seem unusual.
Acute or chronic radiating pain
Unilateral or bilateral lower extremity motor and/or sensory abnormality
Bowel and/or bladder dysfunction
- Initial presentation may be of difficulty starting or stopping a stream of urine that may be followed by frank incontinence first of urine then of stool. Urinary incontinence is on the basis of overflow.
- Usually with associated saddle (perineal) anesthesia (Examiner can inquire if toilet paper feels different when wiping.)

Physical

Pain often is localized to the low back; local tenderness to palpation or percussion may be present.
Reflex abnormalities may be present; they typically include loss or diminution of reflexes. Hyperactive reflexes may signal spinal cord involvement and exclude the diagnosis of cauda equina syndrome (CES).
Pain in the legs (or radiating to the legs) is characteristic of CES.
Sensory abnormality may be present in the perineal area or lower extremities. Light touch in the perineal area should be tested.
Muscle weakness may be present in muscles supplied by affected roots. Muscle wasting may occur if CES is chronic.
Poor anal sphincter tone is characteristic of CES.
Babinski sign or other signs of upper motor neuron involvement suggest a diagnosis other than CES, possibly a diagnosis of spinal cord compression.
Anesthetic areas may show skin breakdown.
Alteration in bladder function may be assessed empirically by obtaining urine via catheterization. A significant volume with little or no urge to void, or as a post-void residual, may indicate bladder dysfunction. Bedside ultrasonography may be also used to estimate or measure post-void residual bladder volume.

Causes

Numerous etiologies of cauda equina syndrome (CES) exist, generally with commonality of compression of the cauda.⁴

Traumatic injury
Lumbar disk herniation⁵
Abscess
Spinal anesthesia
Spinal epidural hematoma
Tumor, either primary or metastatic
Late-stage ankylosing spondylitis
Idiopathic
Inferior vena cava thrombosis⁶
Lymphoma
Sarcoidosis

Differential Diagnoses

Back Pain, Mechanical
Guillain-Barré Syndrome
Lumbar (Intervertebral) Disk Disorders
Neoplasms, Spinal Cord
Spinal Cord Infections
Spinal Cord Injuries

Workup

Imaging Studies

Plain radiography - Unlikely to be helpful in cauda equina syndrome but may be performed in cases of traumatic injury or in search of destructive changes, disk-space narrowing, or spondylolysis
CT with and/or without contrast - Lumbar myelogram followed by CT
MRI - Superiority of MRI over CT only suggested by case reports (Early consultation with the appropriate subspecialty is encouraged to guide imaging studies.)⁷
Ultrasonography may be used to estimate or measure post-void residual volume.

Other Tests

Catheterization for residual urine volume may reveal urinary retention suggesting a neurogenic bladder.

Treatment

Prehospital Care

Prehospital care should focus on associated symptoms related to the pain (ie, what besides the pain is different).

Stabilize acute life-threatening conditions.
Immobilize the spine if traumatic.

Emergency Department Care

No proven medical treatment exists, and therapy generally is directed at the underlying cause of cauda equina syndrome (CES).

For penetrating trauma, steroids have not shown significant benefit. Surgery is controversial. The timing of decompression is controversial, with immediate, early, and late surgical decompression showing varying results.
For mechanical compression of the cauda due to disk herniation, surgical intervention may be indicated.

For more information on treatment, see Further Reading for practice guidelines.^8,9,10

Consultations

Early neurosurgical, neurologic, or orthopedic consultations are recommended, depending on the suspected etiology of CES.

Medication

Appropriate analgesia should be provided for a patient with cauda equina syndrome.

Follow-up

Further Inpatient Care

Admit patients to appropriate service (usually neurology, neurosurgery, or orthopedic surgery) with frequent neurologic checks. Ideally, the admitting physician or service should examine the patient at the time of admission.

Further Outpatient Care

Patients in whom acute cauda equina syndrome (CES) is being considered should not be treated or investigated on an outpatient basis without evaluation by a consultant and/or appropriate imaging.

Transfer

Consider patients with CES for transfer if appropriate subspecialty care is not available.

Complications

Residual weakness, incontinence, impotence, and/or sensory abnormalities are potential problems if therapy is delayed.

Prognosis

The prognosis for CES improves if a definitive cause is identified and appropriate treatment occurs early in the course. Surgical decompression may be performed emergently, or, in some patients, delayed, depending on the etiology.

Patient Education

For excellent patient education resources, visit eMedicine's Brain and Nervous System Center. Also, see eMedicine's patient education article Cauda Equina Syndrome.

Miscellaneous

Medicolegal Pitfalls

Failure to consider the diagnosis of cauda equina syndrome in patients presenting with back pain and with bowel and/or bladder dysfunction
Failure to document history, neurologic examination, or comment on sphincter function in patients with back pain and possible cauda equina syndrome
Failure to consider possible spinal cord involvement with resulting disability

Multimedia

Media file 1: Epidural abscess with effacement of thecal sac in a 56-year-old man.

Media file 2: Conus/epiconus infarction in the setting of sickle cell crisis. Image courtesy of Matthew J. Baker, MD.

Media file 3: Conus/epiconus infarction in the setting of sickle cell crisis in the same patient shown in Media file 2.

Media file 4: Conus/epiconus infarction in the setting of sickle cell crisis in the patient as shown in Media files 2 and 3.

Media file 5: Muscle groups, surface anatomy, peripheral sensory innervation, and dermatomes of the anterior lower limb. Image courtesy of Nicholas Y. Lorenzo, MD.

Media file 6: Muscle groups, surface anatomy, peripheral sensory innervation, and dermatomes of the posterior lower limb. Image courtesy of Nicholas Y. Lorenzo, MD.

References

Mauffrey C, Randhawa K, Lewis C, Brewster M, Dabke H. Cauda equina syndrome: an anatomically driven review. Br J Hosp Med (Lond). Jun 2008;69(6):344-7. [Medline].
Bell DA, Collie D, Statham PF. Cauda equina syndrome: what is the correlation between clinical assessment and MRI scanning?. Br J Neurosurg. Apr 2007;21(2):201-3. [Medline].
Ma B, Wu H, Jia LS, Yuan W, Shi GD, Shi JG. Cauda equina syndrome: a review of clinical progress. Chin Med J (Engl). May 20 2009;122(10):1214-22. [Medline].
Todd NV. An algorithm for suspected cauda equina syndrome. Ann R Coll Surg Engl. May 2009;91(4):358-9; author reply 359-60. [Medline].
Olivero WC, Wang H, Hanigan WC, Henderson JP, Tracy PT, Elwood PW, et al. Cauda equina syndrome (CES) from lumbar disc herniations. J Spinal Disord Tech. May 2009;22(3):202-6. [Medline].
Widge AS, Tomycz ND, Kanter AS. Sacral preservation in cauda equina syndrome from inferior vena cava thrombosis. J Neurosurg Spine. Mar 2009;10(3):257-9. [Medline].
Rooney A, Statham PF, Stone J. Cauda equina syndrome with normal MR imaging. J Neurol. May 2009;256(5):721-5. [Medline].
[Guideline] Institute for Clinical Systems Improvement (ICSI). Adult low back pain. Bloomington (MN): Institute for Clinical Systems Improvement (ICSI); 2008 Nov. [Full Text].
[Guideline] Michigan Quality Improvement Consortium. Management of acute low back pain. Southfield (MI): Michigan Quality Improvement Consortium; 2008 Mar. [Full Text].
[Guideline] Bussieres AE, Taylor JA, Peterson C. Diagnostic imaging practice guidelines for musculoskeletal complaints in adults-an evidence-based approach-part 3: spinal disorders. J Manipulative Physiol Ther. Jan 2008;31(1):33-88. [Medline]. [Full Text].
Ahn UM, Ahn NU, Buchowski JM, et al. Cauda equina syndrome secondary to lumbar disc herniation: a meta-analysis of surgical outcomes. Spine. Jun 15 2000;25(12):1515-22. [Medline].
Boukobza M, Guichard JP, Boissonet M, et al. Spinal epidural haematoma: report of 11 cases and review of the literature. Neuroradiology. Aug 1994;36(6):456-9. [Medline].
Busse JW, Hsu WS. Rapid progression of acute sciatica to cauda equina syndrome. J Manipulative Physiol Ther. Jun 2001;24(5):350-5. [Medline].
Choudhury AR, Taylor JC. Cauda equina syndrome in lumbar disc disease. Acta Orthop Scand. Jun 1980;51(3):493-9. [Medline].
Cohen MS, Wall EJ, Kerber CW, et al. The anatomy of the cauda equina on CT scans and MRI. J Bone Joint Surg Br. May 1991;73(3):381-4. [Medline].
Davis DP, Bruffey JD, Rosen P. Coccygeal fracture and Paget's disease presenting as acute cauda equina syndrome. J Emerg Med. Mar-Apr 1999;17(2):251-4. [Medline].
Delamarter RB, Sherman JE, Carr JB. 1991 Volvo Award in experimental studies. Cauda equina syndrome: neurologic recovery following immediate, early, or late decompression. Spine. Sep 1991;16(9):1022-9. [Medline].
Gleave JR, Macfarlane R. Cauda equina syndrome: what is the relationship between timing of surgery and outcome?. Br J Neurosurg. Aug 2002;16(4):325-8. [Medline].
Hall ED. The neuroprotective pharmacology of methylprednisolone. J Neurosurg. Jan 1992;76(1):13-22. [Medline].
Hussain SA, Gullan RW, Chitnavis BP. Cauda equina syndrome: outcome and implications for management. Br J Neurosurg. Apr 2003;17(2):164-7. [Medline].
Kaiboriboon K, Olsen TJ, Hayat GR. Cauda equina and conus medullaris syndrome in sarcoidosis. Neurologist. May 2005;11(3):179-83. [Medline].
Mohit AA, Fisher DJ, Matthews DC, et al. Inferior vena cava thrombosis causing acute cauda equina syndrome. Case report. J Neurosurg. Jan 2006;104(1 Suppl):46-9. [Medline].
Rigler ML, Drasner K, Krejcie TC, et al. Cauda equina syndrome after continuous spinal anesthesia. Anesth Analg. Mar 1991;72(3):275-81. [Medline].
Rydevik B. Neurophysiology of cauda equina compression. Acta Orthop Scand Suppl. 1993;251:52-5. [Medline].
Rydevik B, Brown MD, Lundborg G. Pathoanatomy and pathophysiology of nerve root compression. Spine. Jan-Feb 1984;9(1):7-15. [Medline].
Small SA, Perron AD, Brady WJ. Orthopedic pitfalls: cauda equina syndrome. Am J Emerg Med. Mar 2005;23(2):159-63. [Medline].

Keywords

cauda equina syndrome, CES, lumbosacral nerve root compression, sciatica, neuromuscular disorders, urogenital disorders, nerve compression, ankylosing spondylitis, bladder dysfunction, bowel dysfunction, herniated disk, disk herniation, spinal stenosis, spinal neoplasm, spinal tumor, low back pain, spinal column, narrowing of the spinal canal, spinal nerves, spinal cord, vertebral column, laminectomy, discectomy, compression of nerve roots, inflammation of nerve roots, CE syndrome, saddle sensory disturbances, variable lower extremity motor loss, variable lower extremity sensory loss, radiating pain, perineal anesthesia, incontinence, painradiating to legs, poor anal sphincter tone, lumbar disc disease, spinal anesthesia, late-stage ankylosing spondylitis

Contributor Information and Disclosures

Author

Michael S Beeson, MD, MBA, FACEP, Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine; Program Director, Emergency Medicine Residency, Summa Health System
Michael S Beeson, MD, MBA, FACEP is a member of the following medical societies: American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, National Association of EMS Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Kirsten A Bechtel, MD, Associate Professor, Department of Pediatrics, Yale University School of Medicine; Attending Physician, Department of Pediatric Emergency Medicine, Yale-New Haven Children's Hospital
Kirsten A Bechtel, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

J Stephen Huff, MD, Associate Professor, Emergency Medicine and Neurology, Department of Emergency Medicine, University of Virginia Health Sciences Center
J Stephen Huff, MD is a member of the following medical societies: American Academy of Emergency Medicine, American Academy of Neurology, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: WebMD Salary Employment

Further Reading

Clinical guidelines

Adult low back pain.
Institute for Clinical Systems Improvement - Private Nonprofit Organization. 2008 Nov. 66 pages. NGC:006888

Management of acute low back pain.
Michigan Quality Improvement Consortium - Professional Association. 2008 Mar. 1 page. NGC:006422

Diagnostic imaging practice guidelines for musculoskeletal complaints in adults - an evidence-based approach. Part 3: spinal disorders.
Bussieres AE, Taylor JA, Peterson C. Diagnostic imaging practice guidelines for musculoskeletal complaints in adults-an evidence-based approach-part 3: spinal disorders. J Manipulative Physiol Ther 2008 Jan;31(1):33-88. [422 references] PubMed. NGC:006703

Clinical trials

IDE Clinical Trial Comparing Coflex vs. Fusion to Treat Lumbar Spinal Stenosis

World Health Organization Disability Assessment Schedule (WHODAS-II) for Patients With Symptomatic Lumbar Disc Herniation

Surgical Treatment Comparison for Recurrent Lumbar Disc Herniation