Management of Suspected Viral Encephalitis with Seizures and Decreased Level of Consciousness
Intravenous acyclovir 10 mg/kg every 8 hours should be initiated immediately for this patient presenting with convulsive attack, decreased level of consciousness, fever, recent viral illness, and CSF findings showing lymphocytosis with low glucose. 1, 2
Immediate Management Priority
This clinical presentation—seizures, decreased consciousness, fever following viral prodrome, and CSF lymphocytosis with low glucose—represents presumed viral encephalitis (likely HSV) until proven otherwise, requiring urgent empiric acyclovir therapy. 1, 2
Critical Initial Actions
Patients with falling level of consciousness require urgent ICU assessment for airway protection, ventilatory support, management of raised intracranial pressure, optimization of cerebral perfusion pressure, and correction of electrolyte imbalances. 1, 2
Immediate neurological specialist consultation should be obtained, with clinical neurological review within 24 hours of presentation. 1, 3
Intravenous acyclovir at 10 mg/kg every 8 hours should be started immediately without waiting for confirmatory testing, as early treatment significantly reduces mortality from 70% to 25% in HSV encephalitis. 2, 4
Why Acyclovir is the Correct Answer (Option A)
Evidence Supporting Acyclovir
The Infectious Diseases Society of America recommends immediate treatment with acyclovir for patients with suspected encephalitis presenting with seizures, along with appropriate antiepileptic medications, at a dosage of 10 mg/kg intravenously every 8 hours in adults with normal renal function. 2
In proven HSV encephalitis, acyclovir treatment for 14-21 days decreased mortality to 25% compared to 59% with older treatments, with 32% of acyclovir-treated patients functioning normally or with only mild sequelae compared to 12% with alternative therapy. 4
The CSF profile described (lymphocytosis with low glucose and elevated protein) is consistent with viral encephalitis, particularly HSV, which can occasionally present with low CSF glucose mimicking bacterial infection. 1
Why NOT Corticosteroids Alone (Option B)
Corticosteroids should NOT be used routinely in patients with HSV encephalitis while awaiting results of a randomized controlled trial. 1
The British Infection Association guidelines explicitly state that corticosteroids may have a role under specialist supervision, but data establishing this are needed—they are NOT first-line therapy. 1
Corticosteroids have strong immunomodulatory effects which could theoretically facilitate viral replication, making monotherapy with steroids potentially harmful. 1
Why NOT Antibiotics Alone (Option C - Ceftriaxone and Vancomycin)
While bacterial meningitis must be considered in the differential diagnosis, the clinical presentation with recent viral prodrome, seizures, and CSF lymphocytosis strongly favors viral encephalitis over bacterial meningitis. 1
Bacterial meningitis typically presents with higher CSF protein, lower glucose ratio, and neutrophilic rather than lymphocytic predominance. 1
However, if there is any diagnostic uncertainty or delay in obtaining CSF results, empiric antibacterial coverage can be added to acyclovir—but acyclovir should never be withheld. 1
Diagnostic Considerations
CSF Interpretation Nuances
A lymphocytic CSF pleocytosis with low glucose can occur in HSV encephalitis (approximately 50% have elevated red cell counts suggesting hemorrhagic component), tuberculosis, partially treated bacterial meningitis, or fungal infections. 1
The clinical context of acute presentation with seizures following viral prodrome strongly favors HSV encephalitis over these alternatives. 1
Initial CSF PCR for HSV can be negative in 5-10% of proven HSV encephalitis cases, especially if obtained early (<72 hours) or late in illness—therefore, a single negative PCR should NOT prompt discontinuation of acyclovir if clinical suspicion remains high. 1
Duration and Monitoring of Acyclovir Therapy
Acyclovir should be continued for 14-21 days in HSV encephalitis, with the dose adjusted for renal function. 1, 2, 4
Acyclovir can be safely discontinued if HSV PCR in CSF is negative once >72 hours after neurological symptom onset, with unaltered consciousness, normal MRI (performed >72 hours after symptom onset), and CSF white cell count <5×10⁶/L. 1
If initial CSF PCR is negative but clinical suspicion remains high, repeat lumbar puncture at 24-48 hours is recommended—HSV encephalitis is very unlikely if two CSF PCRs are negative. 1
Renal function must be monitored closely during IV acyclovir therapy, with adequate hydration maintained to prevent crystalluria and obstructive nephropathy. 4
Adjunctive Seizure Management
Appropriate antiepileptic medications should be administered alongside acyclovir for seizure control. 2
For refractory seizures, IV valproate at 20-30 mg/kg loading dose or levetiracetam 30-60 mg/kg/day are highly effective options. 2
Continuous EEG monitoring should be considered for refractory status epilepticus with escalation to anesthetic agents under ICU care. 2
Critical Pitfalls to Avoid
Never delay acyclovir while awaiting confirmatory testing—the risk-benefit ratio overwhelmingly favors empiric treatment given the high mortality of untreated HSV encephalitis. 2, 4
Do not stop acyclovir based solely on a single negative CSF PCR if obtained early in the illness or if clinical suspicion remains high. 1
Do not use corticosteroids as monotherapy or first-line treatment—they remain controversial and are not routinely recommended. 1
Acyclovir plasma concentrations are higher in geriatric patients due to age-related changes in renal function, requiring dose adjustment in patients with underlying renal impairment. 4