Approach
No specific antiviral treatment is available, and management is supportive. Patients with neuroinvasive disease require immediate medical care with hospitalization, respiratory support, and intravenous fluids.
West Nile fever
A large percentage of cases are mild and self-limited; therefore, treatment is similar to that for most other influenza-like illnesses. Recommend rest, generous fluid intake, and treatment of symptoms with nonprescription medications such as acetaminophen. Advise the patient to seek medical attention if the symptoms can no longer be adequately managed by nonprescription medications (e.g., severe dehydration) or if they last more than 1 week. Advise the patient to seek immediate medical care if they develop signs or symptoms of neuroinvasive disease (e.g., severe headache, photophobia, seizures, or changes in mental state).[3][74][75]
West Nile neuroinvasive disease
Admit patient to hospital, start intensive supportive care immediately (e.g., intravenous fluids, respiratory support, seizure management, infection management, prevention of venous thromboembolism), and manage any other sequelae of meningitis, encephalitis, or paralysis.[3][74][75]
Patients with encephalitis require close monitoring for the development of seizures or elevated intracranial pressure. Patients with encephalitis or poliomyelitis should have their airway monitored as acute respiratory failure can develop rapidly. Ventilatory support for a prolonged period may be required.[27]
Rule out other treatable illnesses such as bacterial meningitis, herpes simplex encephalitis, or Guillain-Barre syndrome. Herpes simplex infection has a definitive effective treatment but is often more difficult to exclude than other treatable conditions such as bacterial meningitis. Therefore, if herpes simplex infection cannot be excluded, and none of the other differentials can be confirmed, give intravenous acyclovir.[76]
There are no specific drug therapies for meningitis, encephalitis, and poliomyelitis caused by West Nile virus, and there is no evidence that antivirals are effective.
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