eMedicine Specialties > Infectious Diseases > CNS Infections
Eastern Equine Encephalitis: Treatment & Medication
Updated: Oct 31, 2007
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
Focus initial medical care on making a prompt diagnosis that differentiates this condition from potentially treatable causes. Because eastern equine encephalitis (EEE) mimics other encephalitides, meningitis, or meningoencephalitis, empiric drug therapy for these conditions should be implemented promptly. Antibiotic therapy for generalized coverage of bacterial meningitis (as appropriate for age and antibiotic resistance patterns) and acyclovir to treat HSV infection should be started until these diseases are ruled out.
- Like all alphaviruses, EEE has no specific treatment. Focus management primarily on supportive and preventive measures.
- Although ribavirin has in vitro activity against this virus, the benefit of administering it in the early viremic stage has not been established.
- Once the patient is comatose, undertake obvious measures (eg, respiratory maintenance with ventilator support in a critical care unit). Additionally, maintain patient nutritional status appropriately.
- If SIADH is present, treat accordingly (see Syndrome of Inappropriate Antidiuretic Hormone Secretion).
- Pharmacologic therapy consists primarily of antipyretics, analgesics, and anticonvulsants.
- Although no current medical therapies exist for EEE, recent research reveals some possibilities. An antibody with appropriate specificity attenuates the intracellular processes necessary for viral replication in animal models. The antibody binds to cell-specific markers of infected cells and initiates an intracellular cascade, which interferes with viral reproduction. Cytotoxic T cells also play an important part in the recovery from CNS lesions in mice. Early studies attempted to use pyrimidine derivatives and isoprinosine, a derivative of inosine, for treatment, but in vivo results were poor.5 Nucleoside analogs (eg, ribavirin) also have in vitro activity, but no clinical application is apparent. Whether or not these therapies can be productive in humans remains questionable.
Surgical Care
No direct surgical treatments for this disease are available except for appropriate neurologic measures necessary to deal with significant CNS bleeding or the consequences of markedly elevated CNS pressure.
Consultations
Consultations are primarily for supportive measures.
- Infectious disease specialist - Particularly relevant when the etiology of the encephalitis or meningoencephalitis is difficult to determine (most important contribution will likely be the ability to rapidly determine a potentially reversible cause of the patient’s symptoms)
- Neurologist - May provide early insightful information and aid with the diagnosis (EEG) and treatment of complications
- Critical care specialist - Valuable for coordinating intensive care unit (ICU) care if general practitioner is treating patient
- Neurosurgeon - Needed only for treatment of complications or brain biopsy
Diet
No special dietary restrictions exist. As with all critically ill patients, carefully provide adequate nutritional support.
Medication
Drugs currently used are those capable of ameliorating neurologic complications. No current studies provide support for or against prophylactic use. Potentially used medications include phenytoin, phenobarbital, or a benzodiazepine drip. Use antipyretics as needed. Additionally, appropriate analgesics and amnestics can be used once the patient is intubated. Antibiotics are not of value in these situations and may predispose patients to superinfections. After determining that the patient does not have a bacterial infection, discontinue antibiotics.
Anticonvulsants
Because of the high prevalence of seizures in patients with eastern equine encephalitis (EEE), these drugs are appropriate.
Dilantin (phenytoin)
May act in motor cortex where may inhibit spread of seizure activity. Activity of brain stem centers responsible for tonic phase of grand mal seizures also may be inhibited. Individualize dose and administer a larger dose before retiring if dose cannot be divided equally. Rate of infusion must not exceed 50 mg/min to avoid hypotension and arrhythmia.
Adult
Loading dose: 15-20 mg/kg PO/IV single or divided doses, followed by 100-150 mg/dose at 30-min intervals
Initial dose: 100 mg (125 mg suspension) PO/IV tid
Maintenance dosage: 300-400 mg/d PO/IV divided tid or qd/bid if using extended release; increase to 600 mg/d (625 mg/d suspension) may be necessary; not to exceed 1500 mg q24h
Pediatric
Loading dose: 15-20 mg/kg PO/IV single or divided doses
Initial dose: 5 mg/kg/d PO/IV divided bid/tid
Maintenance dose: 4-8 mg/kg PO/IV divided bid/tid
< 6 years: Not established
> 6 years: May require minimum adult dose (300 mg/d); not to exceed 300 mg/d
Please consult pharmacist because of multiple drug interactions; amiodarone, benzodiazepines, chloramphenicol, cimetidine, fluconazole, isoniazid, metronidazole, miconazole, phenylbutazone, succinimides, sulfonamides, omeprazole, phenacemide, disulfiram, ethanol (acute ingestion), trimethoprim, and valproic acid may increase phenytoin toxicity; phenytoin effects may decrease when taken concurrently with barbiturates, diazoxide, ethanol (chronic ingestion), rifampin, antacids, charcoal, carbamazepine, theophylline, and sucralfate; phenytoin may decrease effects of acetaminophen, corticosteroids, dicumarol, disopyramide, doxycycline, estrogens, haloperidol, amiodarone, carbamazepine, cardiac glycosides, quinidine, theophylline, methadone, metyrapone, mexiletine, oral contraceptives, and valproic acid
Documented hypersensitivity; sinoatrial block; second- and third-degree AV block; sinus bradycardia; Adams-Stokes syndrome
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Perform blood counts and urinalyses at start of therapy and at monthly intervals for several months thereafter to monitor for blood dyscrasias; discontinue use if a skin rash appears and do not resume use if rash is exfoliative, bullous, or purpuric; rapid IV infusion may result in death from cardiac arrest marked by QRS widening; caution in acute intermittent porphyria and diabetes (may elevate blood sugar); discontinue use if hepatic dysfunction occurs
Diazepam (Valium)
Any of the benzodiazepines may be effective in the short term. Most often, diazepam or lorazepam is recommended. Diazepam depresses all levels of CNS (eg, limbic, reticular formation), possibly by increasing activity of GABA. Individualize dosage and increase cautiously to avoid adverse effects.
Adult
5-15 mg IV q5min, repeat prn titrating to effect; not to exceed 30 mg in 8 h
Pediatric
0.05-0.3 mg/kg/dose IV/IM over 2-3 min q15-30min; repeat in 2-4 h prn; not to exceed 10 mg
Increases toxicity of benzodiazepines in CNS with coadministration of phenothiazines, barbiturates, alcohols, and MAOIs
Documented hypersensitivity; narrow-angle glaucoma
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Sedation, hypotension; caution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity)
Corticosteroids
Early initiation serves multiple purposes (eg, decreases inflammation, decreases cerebral edema, treats potential adrenocortical dysfunction).
Dexamethasone (Decadron, AK-Dex, Alba-Dex)
Potent corticosteroid usually administered IV in these situations. For various allergic and inflammatory diseases. Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reducing capillary permeability.
Adult
16 mg IV, then 4-10 mg IV q6h
Pediatric
0.08-0.3 mg/kg/d or 2.5-10 mg/m2/d divided q6-12h
Effects decrease with coadministration of barbiturates, phenytoin, and rifampin; decreases effect of salicylates and vaccines used for immunization
Documented hypersensitivity; active bacterial or fungal infection
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Increases risk of multiple complications, including severe infections; monitor adrenal insufficiency when tapering drug; abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections are possible complications of glucocorticoid use
Methylprednisolone (Solu-Medrol)
IV steroid often used early. Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Adult
100-150 mg IV, then 60-120 mg IV q6h or 30 mg/kg IV over 15 min followed in 45 min by 5.4 mg/kg/h IV
Pediatric
30 mg/kg IV over 15 min followed in 45 min by 5.4 mg/kg/h IV
Coadministration with digoxin may increase digitalis toxicity secondary to hypokalemia; estrogens may increase levels of methylprednisolone; phenobarbital, phenytoin, and rifampin may decrease levels of methylprednisolone (adjust dose); monitor patients for hypokalemia when taking medication concurrently with diuretics
Documented hypersensitivity; viral, fungal, or tubercular skin infections
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Hyperglycemia, edema, osteonecrosis, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, growth suppression, myopathy, and infections are possible complications of glucocorticoid use
More on Eastern Equine Encephalitis |
| Overview: Eastern Equine Encephalitis |
| Differential Diagnoses & Workup: Eastern Equine Encephalitis |
 Treatment & Medication: Eastern Equine Encephalitis |
| Follow-up: Eastern Equine Encephalitis |
| References |
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Further Reading
Keywords
eastern equine encephalitis, EEE, western equine encephalitis, WEE, St Louis encephalitis, La Crosse encephalitis, West Nile encephalitis, meningoencephalitis, viral encephalitis, herpes simplex virus, arboviruses, alphavirus, Togaviridae family, Culiseta melanura, Coquillettidia perturbans, Aedes canadensis, Venezuelan equine encephalitis, North American eastern equine encephalitis, South American eastern equine encephalitis
