Management of an 11-Year-Old Boy with Prolonged Fever and Neurological Deterioration
Immediate Clinical Assessment
This child requires immediate empiric treatment for viral encephalitis with intravenous acyclovir 10 mg/kg every 8 hours while pursuing urgent diagnostic workup, as the combination of prolonged fever (11 days), ataxia, nystagmus, altered mental status, and bradycardia strongly suggests herpes simplex encephalitis or another serious CNS infection. 1, 2
The constellation of symptoms—particularly the cerebellar signs (ataxia, nystagmus) combined with altered consciousness and bradycardia—indicates brainstem or posterior fossa involvement requiring immediate intervention. 1
Critical Differential Diagnoses to Consider
Primary Considerations:
Viral Encephalitis (HSV, VZV): The 11-day fever history with progressive neurological deterioration (ataxia, nystagmus, drowsiness) is highly consistent with viral encephalitis. HSV encephalitis can present with ataxia and altered consciousness, and mortality at 12 months is 25% with acyclovir treatment versus 59% without. 1, 2
Post-infectious Cerebellitis: VZV-associated cerebellitis commonly presents in children with ataxia and nystagmus, though the altered mental status and bradycardia suggest more severe involvement than typical self-limited cerebellitis. 1
Brainstem Encephalitis: The combination of ataxia, nystagmus, and bradycardia (autonomic dysfunction) suggests brainstem involvement, which can occur with listeriosis, tuberculosis, or viral infections. 1
Posterior Fossa Mass/Hydrocephalus: Cerebellar edema or mass effect causing increased intracranial pressure could explain the bradycardia (Cushing's reflex) and cerebellar signs. 1
Less Likely but Important:
Non-convulsive Status Epilepticus: Can present with encephalopathy without overt seizures, though less common as a primary presentation in CNS infections. 1
Septic Encephalopathy: Uncommon in pediatrics but possible with urinary tract or other bacterial infections. 1
Immediate Management Algorithm
Step 1: Stabilization and Empiric Treatment (Within 30 Minutes)
Start IV acyclovir 10 mg/kg every 8 hours immediately before any diagnostic procedures, as delays in treatment significantly worsen outcomes in HSV encephalitis. 1, 2
Assess airway, breathing, circulation: The drowsiness and potential for deterioration require close monitoring; consider ICU admission. 3
Avoid aspirin: Never use aspirin in children under 16 years due to Reye's syndrome risk, which can present with encephalopathy and hepatic dysfunction following viral illness. 1, 4
Step 2: Urgent Diagnostic Workup (Within 1-2 Hours)
Brain MRI with and without contrast: This is superior to CT for posterior fossa pathology and should be performed urgently. MRI abnormalities are found in 63.9% of children with acute ataxia, with significant findings requiring urgent management in 13.5%. 1
Lumbar puncture with CSF analysis: Obtain opening pressure, cell count, protein, glucose, Gram stain, bacterial culture, and CSF PCR for HSV-1, HSV-2, VZV, and enteroviruses. 1
EEG: Essential to rule out non-convulsive status epilepticus, which occurs in 8% of comatose patients without clinical seizure activity. 1
Blood tests: Complete blood count, electrolytes, liver function tests, renal function, blood cultures, inflammatory markers (CRP, procalcitonin). 3
Step 3: Specific Diagnostic Considerations
Check for rash: Absence of rash does not exclude VZV; encephalitis can occur before, during, or after chickenpox rash, or with no rash at all. 1
Assess for focal neurological signs: The presence of extracerebellar symptoms (altered consciousness, bradycardia) increases the likelihood of significant intracranial pathology requiring urgent intervention. 1
Consider tuberculosis and other bacterial causes: Especially if there are risk factors or if the clinical picture suggests brainstem involvement. 1
Treatment Specifics
Acyclovir Dosing and Duration:
Dose: 10 mg/kg IV every 8 hours (30 mg/kg/day) for proven HSV encephalitis. 2
Duration: Continue for 10 days minimum for HSV encephalitis; adjust based on CSF PCR results and clinical response. 1, 2
Renal adjustment: Monitor renal function; acyclovir requires dose reduction in renal impairment. 2
Supportive Care:
ICU admission: This child meets criteria for PICU admission due to altered mental status, potential airway compromise, and need for close neurological monitoring. 3, 5
Fluid management: Maintain adequate hydration but avoid fluid overload if cerebral edema is suspected. 3
Seizure management: Have benzodiazepines readily available; if seizures occur, treat aggressively. 1
Critical Pitfalls to Avoid
Do not delay acyclovir while awaiting diagnostic results: HSV encephalitis has 25% mortality even with treatment; delays worsen outcomes significantly. 1, 2
Do not assume post-infectious cerebellitis is benign: While VZV cerebellitis is usually self-limited in young children, this patient's altered mental status and bradycardia suggest more severe pathology. 1
Do not miss increased intracranial pressure: Bradycardia with altered consciousness may indicate Cushing's reflex from posterior fossa mass effect or hydrocephalus requiring urgent neurosurgical intervention. 1
Do not use CT alone: CT identifies significant abnormalities in only 29% of children with acute ataxia versus 63.9% with MRI; posterior fossa pathology is particularly poorly visualized on CT. 1
Expected Outcomes and Monitoring
Neurological checks every 1-2 hours: Monitor for deterioration, seizures, or signs of increased intracranial pressure. 3
Repeat imaging if clinical deterioration: Worsening consciousness, new focal signs, or persistent bradycardia warrant repeat MRI. 1
CSF PCR results: Typically available within 24-48 hours; continue acyclovir until HSV is definitively excluded. 1
Prognosis: In HSV encephalitis treated with acyclovir, 32% of patients function normally or with only mild sequelae; patients under 30 years with less severe neurological involvement at presentation have the best outcomes. 2