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Cauda Equina and Conus Medullaris Syndromes: Differential Diagnoses & Workup

Author: Segun T Dawodu, MD, JD, MBA, FAAPMR, FAANEM, CIME, DipMI(RCSed), Former Clinical Instructor, Mount Sinai Medical School; Current Director, Pain and Injuries Rehabilitation Services, PMRehab Pain and Sports Medicine Associates
Coauthor(s): Nicholas Y Lorenzo, MD, Chief Editor, eMedicine Neurology; Consulting Staff, Neurology Specialists and Consultants
Contributor Information and Disclosures

Updated: Feb 10, 2009

Differential Diagnoses

Acute Inflammatory Demyelinating Polyradiculoneuropathy
Multiple Sclerosis
Alcohol (Ethanol) Related Neuropathy
Neurosarcoidosis
Amyotrophic Lateral Sclerosis
Pathophysiology of Chronic Back Pain
Chronic Inflammatory Demyelinating Polyradiculoneuropathy
Spinal Cord Hemorrhage
Dermatomyositis/Polymyositis
Spinal Cord Infarction
Diabetic Neuropathy
Spinal Cord Trauma and Related Diseases
Femoral Mononeuropathy
Spinal Epidural Abscess
HIV-1 Associated Distal Painful Sensorimotor Polyneuropathy
Syringomyelia
HIV-1 Associated Multiple Mononeuropathies
Traumatic Peripheral Nerve Lesions
HIV-1 Associated Myopathies
Tropical Myeloneuropathies
HIV-1 Associated Neuromuscular Complications (Overview)

Other Problems to Be Considered

Abdominal aortic aneurysm
Amyloidosis with deposits in the spinal cord
Ankylosing spondylitis and other spondyloarthropathy
Charcot-Marie-Tooth disease (types 1 and 3)
Guillain-Barré syndrome
Herniated lumbar or sacral disk
Intravascular lymphomatosis
Lipomas within the spine
Lumbar stenosis (multilevel)
Neoplasm in the spine
Paget disease of the spine
Peripheral neuropathy and its various causes
Retroperitoneal mass, including neoplasm and hematoma
Sacral plexus injury (eg, after surgery, such as abdominal-perineal resection, sacral excision, or radical hysterectomy)
Spinal infection/abscess and meningitis
Spina bifida/congenital anomalies of the spine/filum terminale
Spinal degenerative diseases
Spinal hemorrhage
Spondylolisthesis
Tethered cord syndrome/short filum terminale
Vascular intermittent claudication
Back pain

Workup

Laboratory Studies

  • These studies may help to define possible causes and any associated pathology, especially other causes of lesions in the lower spinal cord or cauda equina.
    • CBC count, blood glucose, electrolytes, blood urea nitrogen (BUN), and creatinine - As part of the workup to rule out associated anemia, infection, and renal dysfunction, especially in associated retroperitoneal mass
    • Elevated erythrocyte sedimentation rate (ESR) - May point to an inflammatory pathology
    • Syphilitic serology to rule out meningovascular syphilis

Imaging Studies

  • MRI8,9 with contrast of the lumbosacral spine is the diagnostic test of choice and provides a more complete radiographic assessment of the spine than other tests. Gadolinium contrast MRI is currently the most sensitive imaging for detecting intradural neoplasms. It also may be able to rule out abdominal aneurysm, which could be the source of emboli causing conus medullaris infarction. See Media files 3-5 for representative MRIs.
  • CT scan10 myelogram may reveal an intradural or extradural mass or lesions affecting the conus medullaris.
  • Plain radiographs of the lumbosacral spine are still useful and may depict early changes in vertebral erosions secondary to tumors and spina bifida. Chest radiography is indicated to rule out a pulmonary source of pathology that could affect the lumbosacral spine (eg, malignant tumor, tuberculosis). Follow-up chest CT may be required.
  • Bone scan may detect malignant tumor or metastases and inflammatory conditions affecting the vertebrae.

Other Tests

  • Needle electromyography (EMG)11 may show evidence of acute denervation, especially in cauda equina lesions and multilevel lumbar spinal stenosis. EMG studies also could help in predicting prognosis and monitoring recovery. Performing needle EMG of the bilateral external anal sphincter muscles is recommended.
  • Nerve conduction studies12 , especially of the pudendal nerve, may rule out more distal peripheral nerve lesions.
  • Somatosensory evoked potentials (SSEPs)12 could be done as part of the workup to rule out multiple sclerosis, which could present initially as a lower spinal cord syndrome.
  • Duplex ultrasound of peripheral vessels may rule out compromised vasculature as a possible cause of associated claudication.

Procedures

Lumbar puncture should be performed to examine the CSF to rule out inflammatory disease of the meninges or spinal cord.

More on Cauda Equina and Conus Medullaris Syndromes

Overview: Cauda Equina and Conus Medullaris Syndromes
Differential Diagnoses & Workup: Cauda Equina and Conus Medullaris Syndromes
Treatment & Medication: Cauda Equina and Conus Medullaris Syndromes
Follow-up: Cauda Equina and Conus Medullaris Syndromes
Multimedia: Cauda Equina and Conus Medullaris Syndromes
References
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References

  1. Kingwell SP, Curt A, Dvorak MF. Factors affecting neurological outcome in traumatic conus medullaris and cauda equina injuries. Neurosurgical Focus. 2008;25(5):E7. [Medline].

  2. Fujisawa H, Igarashi S, Koyama T. Acute cauda equina syndrome secondary to lumbar disc herniation mimicking pure conus medullaris syndrome--case report. Neurol Med Chir (Tokyo). Jul 1998;38(7):429-31. [Medline].

  3. Raj D, Coleman N. Cauda equina syndrome secondary to lumbar disc herniation. Acta Orthop Belg. Aug 2008;74(4):522-7. [Medline].

  4. Gleave JR, MacFarlane R. Prognosis for recovery of bladder function following lumbar central disc prolapse. Br J Neurosurg. 1990;4(3):205-9. [Medline].

  5. Gellido CL, Onesti S, Llena J. Spinal schistosomiasis. Neurology. Jan 25 2000;54(2):527. [Medline].

  6. Waters JH, Watson TB, Ward MG. Conus medullaris injury following both tetracaine and lidocaine spinal anesthesia. J Clin Anesth. Dec 1996;8(8):656-8. [Medline].

  7. Kothbauer K, Seiler RW. [Tethered spinal cord syndrome in adults]. Nervenarzt. Apr 1997;68(4):285-91. [Medline].

  8. Spencer TS, Campellone JV, Maldonado I, et al. Clinical and magnetic resonance imaging manifestations of neurosarcoidosis. Semin Arthritis Rheum. 2005;34(4):649-661. [Medline].

  9. Coscia M, Leipzig T, Cooper D. Acute cauda equina syndrome. Diagnostic advantage of MRI. Spine. Feb 15 1994;19(4):475-8. [Medline].

  10. Mathew P, Todd NV. Diagnosis of intradural conus and cauda equina tumours. Br J Hosp Med. Aug 18-31 1993;50(4):169-70, 172-4. [Medline].

  11. Podnar S. Electromyography of the anal sphincter: which muscle to examine?. Muscle Nerve. Sep 2003;28(3):377-9. [Medline].

  12. Rydevik B. Neurophysiology of cauda equina compression. Acta Orthop Scand Suppl. 1993;251:52-5. [Medline].

  13. Biesek D, Ksiazkiewicz B, Wanat-Slupska E. [Conus medullaris and cauda equina infarct in the course of thrombosis of deep veins of lower extremities]. Pol Merkur Lekarski. Sep 2004;17(99):273-4. [Medline].

  14. Butefisch C, Gutmann L, Gutmann L. Compression of spinal cord and cauda equina in Charcot-Marie-Tooth disease type 1A. Neurology. Mar 10 1999;52(4):890-1. [Medline].

  15. Canale S. Circulation of spinal cord. In: Campbell's Operative Orthopaedics. Vol 9. St. Louis, Mo: Mosby; 1998:. 2683.

  16. 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].

  17. Kaiboriboon K, Olsen TJ, Hayat GR. Cauda equina and conus medullaris syndrome in sarcoidosis. Case report and literature review. Neurology. 2005;11(3):179-183. [Medline].

  18. Kostuik JP, Harrington I, Alexander D, et al. Cauda equina syndrome and lumbar disc herniation. J Bone Joint Surg Am. Mar 1986;68(3):386-91. [Medline].

  19. Ku A, Lachmann E, Tunkel R. Neurosarcoidosis of the conus medullaris and cauda equina presenting as paraparesis: case report and literature review. Paraplegia. Feb 1996;34(2):116-20. [Medline].

  20. Mascalchi M, Salvi F, Pirini MG. Transthyretin amyloidosis and superficial siderosis of the CNS. Neurology. Oct 22 1999;53(7):1498-503. [Medline].

  21. Michelson DJ, Ashwal S. Tethered cord syndrome in childhood: diagnostic features and relationship to congenital anomalies. Neurol Res. 2004;26(7):745-753. [Medline].

  22. Nascone JW, Lauerman WC, Wiesel SW. Cauda Equina Syndrome: Is it a surgical emergency?. Univ Pennsylvania Orthoped J. 1999;12:73-6.

  23. Podnar S. Bilateral vs. unilateral electromyographic examination of the external anal sphincter muscle. Neurophysiol Clin. Oct 2004;34(3-4):153-7. [Medline].

  24. Schizas C, Ballesteros C, Roy P. Cauda equina compression after trauma: an unusual presentation of spinal epidural lipoma. Spine. Apr 15 2003;28(8):E148-51. [Medline].

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Further Reading

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Keywords

lower spinal cord injury, compressive lumbosacral polyradiculopathy, cauda equina syndrome, conus medullaris syndrome, spinal cord compression, back pain, spinal cord injury, upper motor neuron symptoms, UMN symptoms, lower motor neuron symptoms, LMN symptoms, spinal cord syndromes

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Contributor Information and Disclosures

Author

Segun T Dawodu, MD, JD, MBA, FAAPMR, FAANEM, CIME, DipMI(RCSed), Former Clinical Instructor, Mount Sinai Medical School; Current Director, Pain and Injuries Rehabilitation Services, PMRehab Pain and Sports Medicine Associates
Segun T Dawodu, MD, JD, MBA, FAAPMR, FAANEM, CIME, DipMI(RCSed) is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American College of Sports Medicine, American Medical Association, American Medical Informatics Association, Association of Academic Physiatrists, International Society of Physical and Rehabilitation Medicine, and Royal College of Surgeons of England
Disclosure: Nothing to disclose.

Coauthor(s)

Nicholas Y Lorenzo, MD, Chief Editor, eMedicine Neurology; Consulting Staff, Neurology Specialists and Consultants
Nicholas Y Lorenzo, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Neurology
Disclosure: Nothing to disclose.

Medical Editor

Milind J Kothari, DO, Professor and Vice-Chair, Department of Neurology, Pennsylvania State University College of Medicine; Consulting Staff, Department of Neurology, Hershey Medical Center
Milind J Kothari, DO is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Neurological Association
Disclosure: Nothing to disclose.

Pharmacy Editor

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

Managing Editor

James H Halsey, MD, Professor, Department of Neurology, University of Alabama Medical Center
James H Halsey, MD is a member of the following medical societies: American Academy of Neurology, American Heart Association, American Medical Association, American Neurological Association, American Society of Neuroimaging, Medical Association of the State of Alabama, New York Academy of Sciences, Pan American Medical Association, Sigma Xi, Society for Neuroscience, and Southern Medical Association
Disclosure: Nothing to disclose.

CME Editor

Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association
Disclosure: Nothing to disclose.

Chief Editor

Nicholas Y Lorenzo, MD, Chief Editor, eMedicine Neurology; Consulting Staff, Neurology Specialists and Consultants
Nicholas Y Lorenzo, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Neurology
Disclosure: Nothing to disclose.

 
 
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