Approach

There is no specific antiviral treatment available, and management involves supportive care for symptomatic patients, as well as close monitoring for the development of complications.[41]​ Asymptomatic patients do not require treatment. Eastern equine encephalitis virus (​EEEV) infection is a notifiable condition; report all cases to your local health authority.

Supportive care for symptomatic patients

Patients with febrile illness require supportive care. In the absence of neurological symptoms, febrile illness usually resolves in 1 to 2 weeks.[4]​ Supportive care for patients with febrile illness includes ample oral fluid intake (i.e., enough fluids to be passing clear urine) and use of analgesics and/or antipyretics (e.g., paracetamol). 

If there is severe dehydration due to vomiting and diarrhoea, admit the patient to hospital, if possible, and treat with oral or intravenous fluids, along with an anti-emetic (e.g., ondansetron).

  • Initial administration of a single oral dose of ondansetron may obviate the need for intravenous fluids or hospitalisation in children.[56]

  • Other anti-emetics are not recommended due to lack of benefit and risk of adverse effects.

Management of neurological symptoms

If neurological symptoms are present, they tend to appear several days into the course of illness and may include irritability, drowsiness, altered mental status, disorientation, ataxia, seizures, paresis, cranial nerve palsies, focal weakness, and meningismus.

  • Patients exhibiting neurological symptoms require hospitalisation, if possible, and close monitoring for the development of seizures, cerebral oedema, and intracranial hypertension.[41] Admission to the intensive care unit may be required. ​

  • Patients with severe meningeal symptoms may require analgesia for headaches, as well as an anti-emetic and rehydration for associated nausea and vomiting.[41]

Administer anticonvulsants if there is seizure activity or a history of seizures.

  • Benzodiazepines are preferred for the initial management of seizures, with lorazepam being most effective due to its long half-life.

  • Phenytoin is recommended if a second drug is needed to terminate seizures. In pregnant women, phenytoin is only used in life-threatening infection, because it is teratogenic.

  • If a patient is taking certain anticonvulsants, such as phenytoin, serum drug levels are monitored to ensure that therapeutic levels are achieved.

Closely monitor the patient’s airway.[41]

  • The airway is secured by intubation if the patient has altered mental status (e.g., obtundation) and mechanical ventilation is initiated.

Perform a cranial nerve examination, fundoscopic examination, and head computed tomography (CT) or brain magnetic resonance imaging (MRI) scan to evaluate for cerebral oedema and elevated intracranial pressure.

  • If intracranial pressure is elevated, consider head elevation, hyperventilation, and intravenous mannitol to reduce pressure.[57]

  • In such instances, the placement of an external ventricular device is recommended.

Start empirical antimicrobial therapy in patients with suspected encephalitis.

  • Empirical treatment with intravenous aciclovir, to cover for possible herpes simplex virus infection, is recommended in patients with cerebrospinal fluid or imaging findings suggesting viral encephalitis; or if these results will not be available within 6 hours; or if the patient is deteriorating.[54]

  • Empirical antibiotic therapy is recommended until bacterial encephalitis has been ruled out.[53]

  • If meningitis or meningoencephalitis is suspected, droplet precautions may be necessary in hospitalised patients until bacterial infections are excluded (follow your local protocols).

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