Last reviewed: 26 Jan 2021
Last updated: 20 Sep 2019
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
- multi-focal chorioretinal lesions
- chorioretinitis and inflammatory vitritis
- seizures
- respiratory distress
- jaundice
- epigastric tenderness
- mild confusion
- disorientation
- stupor/coma
- neck stiffness
- Kernig's sign
- Brudzinski's sign
- muscle paralysis
- parkinsonism
- ataxia
- myoclonus
- tremors
Other diagnostic factors
- nausea/vomiting
- generalised muscle weakness
- splenomegaly
- retinal haemorrhages
- chest pain, dyspnoea, palpitations
- photophobia
- depression
- loss of memory
- bowel and bladder dysfunction
- cranial nerve palsies
Risk factors
- living in/visiting areas with high West Nile virus activity
- mosquito bites
- blood transfusion
- organ transplant
- needle-stick injuries
Diagnostic investigations
1st investigations to order
- serology
- cerebrospinal fluid (CSF) analysis
- full blood count
- serum electrolytes
- liver function tests
- serum amylase/lipase
Investigations to consider
- MRI brain
- CT head
- viral culture or reverse transcriptase-polymerase chain reaction (RT-PCR)
Treatment algorithm
Contributors
Authors

Associate Professor of International Health
Director
Global Obesity Prevention Center
Director of Operations Research
International Vaccine Access Center (IVAC)
Johns Hopkins School of Public Health
Baltimore
MD
Disclosures
BYL declares that he has no competing interests.
Peer reviewers
Executive Scientific Officer
American Red Cross
Gaithersburg
MD
Disclosures
SS declares that she has no competing interests.
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