What is the management (Mx) for a 20-day-old infant presenting with fever, hypotension, tachycardia, and decreased movement, with no apparent focus of infection?

Management of a 20-Day-Old Febrile Infant

This 20-day-old infant with fever (38.3°C), decreased movement, and no identifiable focus of infection requires immediate hospitalization with full sepsis workup (blood, urine, and CSF cultures) followed by empiric IV antibiotics—the answer is D. 1

Rationale for Immediate Action

Age-Specific Risk Assessment

• Infants ≤28 days old with fever ≥38.0°C require complete sepsis evaluation regardless of clinical appearance. 1 This is non-negotiable because well-appearing febrile neonates can still harbor serious bacterial infections, with only 58% of those with bacteremia or bacterial meningitis appearing clinically ill. 1

• The risk of serious bacterial infection in neonates aged 3-28 days is approximately 13%, significantly higher than in older infants. 1 At 20 days old, this infant falls squarely into the highest-risk category where decreased movement represents a concerning clinical sign that may indicate early sepsis. 2

Required Diagnostic Workup

The complete sepsis evaluation must include: 1

• Blood culture (to detect bacteremia with prevalence of 1.1-2.1% in this age group) 2
• Urine culture via catheterization (not bag collection) 2
• Cerebrospinal fluid analysis and culture (bacterial meningitis prevalence 0.4-0.6% with potentially devastating consequences if missed) 1
• Complete blood count with differential 1

Empiric Antibiotic Regimen

Immediately after obtaining cultures, start: 2, 1

• Ampicillin 150 mg/kg/day IV divided every 8 hours (for this 20-day-old infant) 2, 3
• PLUS either:
  • Ceftazidime 150 mg/kg/day IV divided every 8 hours, OR 2
  • Gentamicin 4 mg/kg IV every 24 hours 2, 4

This combination provides coverage for Group B Streptococcus, E. coli, Listeria monocytogenes, and other common neonatal pathogens. 4, 3

Mandatory Hospitalization

All febrile infants ≤28 days old require hospitalization in a facility with staff experienced in neonatal care. 2, 1 The clinical presentation of decreased movement alongside fever represents potential early shock, which in neonates can manifest as altered mental status before hypotension develops. 2

Why Other Options Are Incorrect

• Option A (discharge home): Absolutely contraindicated. This violates fundamental guidelines for neonatal fever management and places the infant at unacceptable risk of untreated meningitis or sepsis. 1

• Option B (return for feeding difficulty): Dangerously inappropriate. Waiting for feeding difficulty means waiting for clinical deterioration—by then, bacterial meningitis or sepsis may have progressed significantly. 1

• Option C (observation only): Inadequate. Observation without antibiotics after obtaining cultures is not acceptable for infants ≤28 days old, even if they appear well. 1

Critical Pitfalls to Avoid

• Never delay lumbar puncture or antibiotics because the infant appears "well enough"—this is the most dangerous error in neonatal fever management. 1

• Never use oral antibiotics or attempt outpatient management in this age group. 1

• Never skip CSF analysis in infants 22-28 days old—the risk of missing bacterial meningitis is unacceptable. 1

Duration and Follow-Up

• Continue empiric antibiotics until culture results are available at 24-36 hours. 2
• If all cultures remain negative at 24-36 hours and the infant is clinically well or improving, antibiotics may be discontinued. 2
• If cultures are positive, switch to targeted antimicrobial therapy for the appropriate duration based on the specific organism and infection site. 2