eMedicine Specialties > Physical Medicine and Rehabilitation > Medical Diseases

West Nile Virus: Differential Diagnoses & Workup

Author: Jess D Salinas Jr, MD, Medical Director, Lake Mary Clinic, National Pain Institute, LLC; Associate Medical Director, Winter Park Clinic, National Pain Institute, LLC
Coauthor(s): Monica L Steiner, MD, Clinical Assistant Professor, Program Director, Department of Orthopedics and Rehabilitation, Loyola University Medical Center
Contributor Information and Disclosures

Updated: Nov 6, 2009

Differential Diagnoses

Acute Poliomyelitis
Guillain-Barre Syndrome
Multiple Sclerosis
Postpolio Syndrome
Vertebrobasilar Stroke

Other Problems to Be Considered

Bacterial meningitis
Viral meningitis
Ischemic stroke
Hemorrhagic stroke
Brain abscess
Brain tumor
Cat-scratch disease
Herpes simplex
Herpes simplex encephalitis
Myasthenia gravis
Hypoglycemia
Leptospirosis
Subarachnoid hemorrhage
Tick-borne diseases, Lyme
Tick-borne diseases, Rocky Mountain spotted fever
Toxoplasmosis
Tuberculosis

Workup

Laboratory Studies

  • The complete blood count (CBC) may show elevated or normal leukocytes values.
  • In cases of encephalitis, hyponatremia may be present. The complication of syndrome of inappropriate ADH (SIADH) secretion is a possibility.
  • Cerebrospinal fluid (CSF) analysis may reveal elevated protein and increased leukocyte levels, with predominant lymphocytes.13 Glucose levels are usually normal rather than decreased.
  • Serologic testing to detect immunoglobulin M (IgM) antibodies is currently the best means14 of diagnosing West Nile virus infection.
    • IgM antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) has been used to detect IgM for the West Nile virus by using serum or CSF samples.1
    • False-positive results may occur because of the close relationship of the West Nile virus to other flaviviruses.
    • In light of this limitation, the plaque reduction neutralization test (PRNT) may help to identify false-positive MAC-ELISA results caused by cross-reactions by other flaviviruses.

Imaging Studies

  • In acute disease, computed tomography (CT) scans do not show any evidence of abnormalities.
  • In an estimated one third of infected individuals, magnetic resonance imaging (MRI) scans show notable enhancement in the leptomeninges and periventricular areas.

Histologic Findings

Autopsy findings in some patients with West Nile virus infection reveal mononuclear inflammation that extensively involves the medulla, with some involvement of the cranial nerve roots.15 However, these findings are not diagnostic for the infection.

More on West Nile Virus

Overview: West Nile Virus
Differential Diagnoses & Workup: West Nile Virus
Treatment & Medication: West Nile Virus
Follow-up: West Nile Virus
References
Further Reading
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References

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  2. Brinton MA. Host factors involved in West Nile virus replication. Ann N Y Acad Sci. Dec 2001;951:207-19. [Medline].

  3. Kramer LD, Bernard KA. West Nile virus in the western hemisphere. Curr Opin Infect Dis. Oct 2001;14(5):519-25. [Medline].

  4. Centers for Disease Control and Prevention. Provisional surveillance summary of the West Nile virus epidemic--United States, January-November 2002. MMWR Morb Mortal Wkly Rep. Dec 20 2002;51(50):1129-33. [Medline].

  5. Centers for Disease Control and Prevention. West Nile virus update--United States, January 1-November 13, 2007. MMWR Morb Mortal Wkly Rep. Nov 16 2007;56(45):1191-2. [Medline].

  6. Asnis DS, Conetta R, Teixeira AA, et al. The West Nile Virus outbreak of 1999 in New York: the Flushing Hospital experience. Clin Infect Dis. Mar 2000;30(3):413-8. [Medline].

  7. Campbell GL, Marfin AA, Lanciotti RS, et al. West Nile virus. Lancet Infect Dis. Sep 2002;2(9):519-29. [Medline].

  8. Nash D, Mostashari F, Fine A, et al. The outbreak of West Nile virus infection in the New York City area in 1999. N Engl J Med. Jun 14 2001;344(24):1807-14. [Medline]. [Full Text].

  9. Moorthi S, Schneider WN, Dombovy ML. Rehabilitation outcomes in encephalitis--a retrospective study 1990-1997. Brain Inj. Feb 1999;13(2):139-46. [Medline].

  10. Verma S, Lo Y, Chapagain M, Lum S, et al. West Nile virus infection modulates human brain microvascular endothelial cells tight junction proteins and cell adhesion molecules: Transmigration across the in vitro blood-brain barrier. Virology. Mar 15 2009;385(2):425-33. [Medline].

  11. Centers for Disease Control and Prevention. Acute flaccid paralysis syndrome associated with West Nile virus infection--Mississippi and Louisiana, July-August 2002. MMWR Morb Mortal Wkly Rep. Sep 20 2002;51(37):825-8. [Medline].

  12. Centers for Disease Control and Prevention. Update: Investigations of West Nile virus infections in recipients of organ transplantation and blood transfusion--Michigan, 2002. MMWR Morb Mortal Wkly Rep. Oct 4 2002;51(39):879. [Medline].

  13. Petzold A, Groves M, Leis AA, et al. Neuronal and glial cerebrospinal fluid protein biomarkers are elevated after West Nile Virus infection. Muscle Nerve. Sep 29 2009;[Medline].

  14. Zaayman D, Human S, Venter M. A highly sensitive method for the detection and genotyping of West Nile virus by real-time PCR. J Virol Methods. May 2009;157(2):155-60. [Medline].

  15. Sampson BA, Armbrustmacher V. West Nile encephalitis: the neuropathology of four fatalities. Ann N Y Acad Sci. Dec 2001;951:172-8. [Medline].

  16. Greve KW, Houston RJ, Adams D, et al. The neurobehavioural consequences of St. Louis encephalitis infection. Brain Inj. Oct 2002;16(10):917-27. [Medline].

  17. Sejvar JJ, Curns AT, Welburg L, et al. Neurocognitive and functional outcomes in persons recovering from West Nile virus illness. J Neuropsychol. Sep 2008;2:477-99. [Medline].

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  22. Anderson JF, Main AJ, Ferrandino FJ, et al. Nocturnal activity of mosquitoes (Diptera: Culicidae) in a West Nile virus focus in Connecticut. J Med Entomol. Nov 2007;44(6):1102-8. [Medline].

  23. Centers for Disease Control and Prevention. Intrauterine West Nile virus infection--New York, 2002. MMWR Morb Mortal Wkly Rep. Dec 20 2002;51(50):1135-6. [Medline].

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  28. Glass JD, Samuels O, Rich MM. Poliomyelitis due to West Nile virus. N Engl J Med. Oct 17 2002;347(16):1280-1. [Medline].

  29. Hubalek Z. Comparative symptomatology of West Nile fever. Lancet. Jul 28 2001;358(9278):254-5. [Medline].

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  35. Styer LM, Kent KA, Albright RG, et al. Mosquitoes inoculate high doses of West Nile virus as they probe and feed on live hosts. PLoS Pathog. Sep 14 2007;3(9):1262-70. [Medline]. [Full Text].

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  37. Wang T, Anderson JF, Magnarelli LA, et al. West Nile virus envelope protein: role in diagnosis and immunity. Ann N Y Acad Sci. Dec 2001;951:325-7. [Medline].

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Further Reading

Clinical guidelines:
Interim guidelines for the evaluation of infants born to mothers infected with West Nile virus during pregnancy. Centers for Disease Control and Prevention - Federal Government Agency [U.S.]. 2004 Feb 27. 4 pages. NGC:003471

The management of encephalitis: clinical practice guidelines by the Infectious Diseases Society of America. Infectious Diseases Society of America - Medical Specialty Society. 2008 Aug 1. 25 pages. NGC:007083

Clinical trials:
Treatment of West Nile Virus With MGAWN1 (PARADIGM)

VRC 300: Screening of Healthy Volunteers for Clinical Trials of Investigational Vaccines to Prevent Infectious Diseases

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Keywords

West Nile virus, West Nile symptoms, West Nile virus symptoms, WNV, , West Nile fever, West Nile encephalitis, West Nile virus mosquitoes, West Nile fever, West Nile infection, mosquito bites, mosquitoes, mosquitoes, mosquitoes

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Contributor Information and Disclosures

Author

Jess D Salinas Jr, MD, Medical Director, Lake Mary Clinic, National Pain Institute, LLC; Associate Medical Director, Winter Park Clinic, National Pain Institute, LLC
Jess D Salinas Jr, MD is a member of the following medical societies: American Academy of Pain Management, American Academy of Pain Medicine, American Academy of Physical Medicine and Rehabilitation, American Medical Association, American Society of Interventional Pain Physicians, and Physiatric Association of Spine, Sports and Occupational Rehabilitation
Disclosure: Emedicine Honoraria Other

Coauthor(s)

Monica L Steiner, MD, Clinical Assistant Professor, Program Director, Department of Orthopedics and Rehabilitation, Loyola University Medical Center
Monica L Steiner, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

Medical Editor

Elizabeth A Moberg-Wolff, MD, Associate Professor and Pediatric PM&R Fellowship Director, Department of Physical Medicine and Rehabilitation, Medical College of Wisconsin; Program Director, Tone Management and Mobility, Department of Physical Medicine and Rehabilitation, Children's Hospital of Wisconsin
Elizabeth A Moberg-Wolff, MD is a member of the following medical societies: American Academy for Cerebral Palsy and Developmental Medicine and American Academy of Physical Medicine and Rehabilitation
Disclosure: Medtronic Neurological Grant/research funds Speaking and teaching

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Kat Kolaski, MD, Assistant Professor, Departments of Orthopedic Surgery and Pediatrics, Wake Forest University School of Medicine
Kat Kolaski, MD is a member of the following medical societies: American Academy for Cerebral Palsy and Developmental Medicine and American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

CME Editor

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

Chief Editor

Consuelo T Lorenzo, MD, Consulting Staff, Department of Physical Medicine and Rehabilitation, Alegent Health Care, Immanuel Rehabilitation Center
Consuelo T Lorenzo, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

 
 
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