eMedicine Specialties > Physical Medicine and Rehabilitation > Plexopathy

Radiation-Induced Lumbosacral Plexopathy: Differential Diagnoses & Workup

Author: Rajesh R Yadav, MD, Assistant Professor, Section of Physical Medicine and Rehabilitation, MD Anderson Cancer Center, University of Texas at Houston
Contributor Information and Disclosures

Updated: Oct 17, 2008

Differential Diagnoses

Chronic Inflammatory Demyelinating Polyradiculoneuropathy
Diabetic Lumbosacral Plexopathy
Lumbar Degenerative Disk Disease
Mononeuritis Multiplex
Neoplastic Lumbosacral Plexopathy

Other Problems to Be Considered

Meningeal carcinomatosis, also known as leptomeningeal disease, may cause subacute motor or sensory deficits to be present with low back or leg pain. In addition, patients with meningeal carcinomatosis often also have mental status changes, headaches, cranial nerve palsies, and/or nuchal rigidity. In cancer patients with thrombocytopenia, retroperitoneal bleeding can cause plexopathy, with a rapid onset of pain and neurologic signs that usually are developed fully in 24 hours. Other associated findings include flank, thigh, or low back ecchymoses. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), which is felt to be immune mediated, can cause severe, symmetrical, peripheral neurologic deficits.  Nerve root thickening may be noted in the lumbosacral plexus, a finding that may be associated with moderate gadolinium enhancement.6

Causes of lumbosacral plexopathy not related to cancer include aortic aneurysms, diabetes mellitus (DM), obstetric procedures, trauma, and intragluteal injections.7,8 With aortic aneurysms, acute pain commonly is seen, and the resultant weakness typically worsens over 1-2 weeks and then stabilizes. A pulsatile rectal or abdominal mass also can be seen in many patients. Acute thigh pain with acute or insidious onset of weakness can result from diabetic amyotrophy and can be difficult to differentiate from the aortic aneurysms. Weakness with diabetic amyotrophy usually is noted proximally, with relative sparing of distal lower extremity muscles.

Workup

Imaging Studies

  • Routine spine and pelvis radiographs and myelograms are unremarkable in lumbosacral plexopathy.
  • The diagnosis of radiation plexopathy can be supported by diagnostic studies, such as computed tomography (CT) scanning and magnetic resonance imaging (MRI) of the pelvis. MRI is more sensitive than is CT scanning in detecting tumor recurrence.9,10 Enhancement of nerve roots and T2-weighted hyperintensity usually suggests tumor. Unfortunately, differentiation from tumor recurrence remains difficult. Generally, radiation plexopathy does not produce nerve enhancement. Positron emission tomography (PET) scanning with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) may be helpful in diagnosing recurrent tumor.

Other Tests

  • Electromyography (EMG) reveals myokymic discharges in most patients (57%) with radiation-induced lumbosacral plexopathy. Such changes occur over years; however, the absence of myokymia does not exclude radiation injury. EMG in clinically weak muscles also may reveal fibrillation potentials (ie, chronic, neurogenic motor unit changes with decreased recruitment). Paraspinal involvement occurs in 50% of cases. Compound muscle action potential (CMAP) of motor nerves may be low.11,12

More on Radiation-Induced Lumbosacral Plexopathy

Overview: Radiation-Induced Lumbosacral Plexopathy
Differential Diagnoses & Workup: Radiation-Induced Lumbosacral Plexopathy
Treatment & Medication: Radiation-Induced Lumbosacral Plexopathy
Follow-up: Radiation-Induced Lumbosacral Plexopathy
References
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References

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  2. Ashenhurst EM, Quartey GR, Starreveld A. Lumbo-sacral radiculopathy induced by radiation. Can J Neurol Sci. Nov 1977;4(4):259-63. [Medline].

  3. Jaeckle KA, Young DF, Foley KM. The natural history of lumbosacral plexopathy in cancer. Neurology. Jan 1985;35(1):8-15. [Medline].

  4. Abu-Rustum NR, Rajbhandari D, Glusman S, et al. Acute lower extremity paralysis following radiation therapy for cervical cancer. Gynecol Oncol. Oct 1999;75(1):152-4. [Medline].

  5. Iglicki F, Coffin B, Ille O, et al. Fecal incontinence after pelvic radiotherapy: evidences for a lumbosacral plexopathy. Report of a case. Dis Colon Rectum. Apr 1996;39(4):465-7. [Medline].

  6. Jaeckle KA. Neurological manifestations of neoplastic and radiation-induced plexopathies. Semin Neurol. Dec 2004;24(4):385-93. [Medline].

  7. Ozkavukcu E, Cayli E, Yagci C, et al. Ruptured iliac aneurysm presenting as lumbosacral plexopathy. Diagn Interv Radiol. Mar 2008;14(1):26-8. [Medline]. [Full Text].

  8. Abdellaoui A, West NJ, Tomlinson MA, et al. Lower limb paralysis from ischaemic neuropathy of the lumbosacral plexus following aorto-iliac procedures. Interact Cardiovasc Thorac Surg. Aug 2007;6(4):501-2. [Medline]. [Full Text].

  9. Moskovic E, Curtis S, A'Hern RP, et al. The role of diagnostic CT scanning of the brachial plexus and axilla in the follow-up of patients with breast cancer. Clin Oncol (R Coll Radiol). Mar 1992;4(2):74-7. [Medline].

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  13. Pritchard J, Anand P, Broome J, et al. Double-blind randomized phase II study of hyperbaric oxygen in patients with radiation-induced brachial plexopathy. Radiother Oncol. Mar 2001;58(3):279-86. [Medline].

  14. Enevoldson TP, Scadding JW, Rustin GJ, et al. Spontaneous resolution of a postirradiation lumbosacral plexopathy. Neurology. Nov 1992;42(11):2224-5. [Medline].

  15. Bradley WG, Fewings JD, Cumming WJ, et al. Delayed myeloradiculopathy produced by spinal X-irradiation in the rat. J Neurol Sci. Jan-Feb 1977;31(1):63-82. [Medline].

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  17. Dahele M, Davey P, Reingold S, et al. Radiation-induced lumbo-sacral plexopathy (RILSP): an important enigma. Clin Oncol (R Coll Radiol). Jun 2006;18(5):427-8. [Medline].

  18. Glantz MJ, Burger PC, Friedman AH. Treatment of radiation-induced nervous system injury with heparin and warfarin. Neurology. Nov 1994;44(11):2020-7. [Medline].

  19. Stryker JA, Sommerville K, Perez R, et al. Sacral plexus injury after radiotherapy for carcinoma of cervix. Cancer. Oct 1 1990;66(7):1488-92. [Medline].

  20. Stubgen JP. Neuromuscular disorders in systemic malignancy and its treatment. Muscle Nerve. Jun 1995;18(6):636-48. [Medline].

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Further Reading

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Keywords

radiation-induced lumbosacral plexopathy, radiation induced lumbosacral plexopathy, plexopathy, plexus, lumbosacral, lumbar sacral, lumbosacral plexus, spine lumbosacral, radiation therapy, radiation plexopathy, motor deficits, limb weakness

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Contributor Information and Disclosures

Author

Rajesh R Yadav, MD, Assistant Professor, Section of Physical Medicine and Rehabilitation, MD Anderson Cancer Center, University of Texas at Houston
Rajesh R Yadav, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

Medical Editor

Robert J Kaplan, MD, Associate Professor, Department of Physical Medicine and Rehabilitation, University of Kansas School of Medicine and Medical Center
Robert J Kaplan, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, Association of Academic Physiatrists, International Spine Intervention Society, and Physiatric Association of Spine, Sports and Occupational Rehabilitation
Disclosure: Nothing to disclose.

Pharmacy Editor

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

Managing Editor

Michael T Andary, MD, MS, Residency Program Director, Professor, Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine
Michael T Andary, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, and Association of Academic Physiatrists
Disclosure: allergan Honoraria Speaking and teaching

CME Editor

Kelly L Allen, MD, Regional Medical Director, IMX-Medical Management Services
Disclosure: Nothing to disclose.

Chief Editor

Robert H Meier III, MD, Director, Amputee Services of America; Active Medical Staff, Presbyterian/St Luke's Hospital, Spalding Rehabilitation Hospital, Select Specialty Hospital; Consulting Staff, Kindred Hospital
Robert H Meier III, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation and Association of Academic Physiatrists
Disclosure: Nothing to disclose.

 
 
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