Last reviewed: 27 Apr 2023
Last updated: 02 Mar 2023
Summary
Definition
History and exam
Key diagnostic factors
- fever of sudden onset
- malaise
- myalgia
- arthralgia
- pharyngitis
- anorexia
- abdominal pain
- visual disturbances
- headache
- rash
- lymphadenopathy
- conjunctival injection
- multifocal chorioretinal lesions
- chorioretinitis and inflammatory vitritis
- seizures
- respiratory distress
- jaundice
- epigastric tenderness
- mild confusion
- disorientation
- stupor/coma
- neck stiffness
- Kernig sign
- Brudzinski sign
- muscle paralysis
- parkinsonism
- ataxia
- myoclonus
- tremors
More key diagnostic factors
Other diagnostic factors
- nausea/vomiting
- generalized muscle weakness
- splenomegaly
- retinal hemorrhages
- chest pain, dyspnea, palpitations
- photophobia
- depression
- loss of memory
- bowel and bladder dysfunction
- cranial nerve palsies
Other diagnostic factors
Risk factors
- living in/visiting areas with high West Nile virus activity
- mosquito bites
- blood transfusion
- organ transplant
- needlestick injuries
More risk factors
Diagnostic investigations
1st investigations to order
- serology
- cerebrospinal fluid (CSF) analysis
- complete blood count
- serum electrolytes
- liver function tests
- serum amylase/lipase
More 1st investigations to order
Investigations to consider
- MRI brain
- CT head
- viral culture or reverse transcriptase-polymerase chain reaction (RT-PCR)
More investigations to consider
Treatment algorithm
ACUTE
West Nile fever
West Nile neuroinvasive disease
Contributors
Authors
Bruce Y. Lee, MD, MBA

Professor of Health Policy and Management
Executive Director
Center for Advanced Technology and Communication for Health (CATCH)
Public Health Informatics Computational and Operation Research (PHICOR)
City University of New York (CUNY)
New York
NY
Disclosures
BYL declares that he has no competing interests.
Peer reviewers
Susan Stramer, PhD
Executive Scientific Officer
American Red Cross
Gaithersburg
MD
Disclosures
SS declares that she has no competing interests.
Differentials
- Herpes simplex encephalitis
- St. Louis encephalitis
- Eastern equine encephalitis
More DifferentialsGuidelines
- West Nile virus surveillance and control guidelines
- A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases
More GuidelinesLog in or subscribe to access all of BMJ Best Practice
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