What is the appropriate management for a full-term infant presenting with fever?

Management of Febrile Full-Term Infant

This infant requires immediate hospitalization, full septic workup (blood culture, catheterized urine culture, and lumbar puncture), and empiric intravenous antibiotics started immediately after cultures are obtained. 1, 2

Age-Specific Risk Stratification

The age of this infant is critical for determining management:

• If 0-28 days old (neonate): This infant is at the highest risk for serious bacterial infections including bacteremia (4.8%) and bacterial meningitis, with 25% having serious bacterial illness. 1, 3 Mandatory full evaluation and hospitalization with no exceptions. 1, 4

• If 29-60 days old: Still considered high-risk with mandatory full evaluation and hospitalization required. 1, 2 The relatively immature immune system at 2 months places this infant in the highest-risk category. 2

• If 61-90 days old: Risk stratification approaches exist but are not universally recommended, and the safest approach remains full evaluation due to mortality and morbidity risks of missed meningitis. 1

Mandatory Diagnostic Workup

Complete the following tests immediately, in this order: 1, 2, 4

1. Confirm fever with rectal temperature ≥38.0°C (100.4°F) 1, 2, 4

2. Blood culture - mandatory for all febrile infants 0-60 days before antibiotics 1, 2, 4

3. Urine culture via catheterization - never use bag collection (catheterization has 95% sensitivity and 99% specificity) 1, 2, 4

4. Lumbar puncture with CSF analysis - essential for all infants 0-60 days, as clinical examination cannot reliably exclude meningitis even in well-appearing infants 1, 2, 4

Empiric Antibiotic Therapy

Initiate antibiotics immediately after obtaining cultures - do not delay for imaging or subspecialty consultation. 1, 2

Standard regimen (no meningitis confirmed): 2, 4

• Ampicillin IV 150 mg/kg/day divided every 8 hours
• PLUS either:
  • Ceftazidime IV 150 mg/kg/day divided every 8 hours, OR
  • Gentamicin IV 4 mg/kg/dose every 24 hours

If meningitis confirmed by CSF: 2, 4

• Ampicillin IV 300 mg/kg/day divided every 6 hours (doubled dose)
• PLUS Ceftazidime IV 150 mg/kg/day divided every 8 hours

Hospitalization Requirements

All febrile infants 0-60 days require hospitalization in a unit with nurses and staff experienced in caring for young infants, regardless of how well they appear clinically. 1, 2, 4

Monitoring for Clinical Deterioration

Watch for these signs requiring immediate intervention: 2, 4

• Toxic appearance or altered mental status
• Poor perfusion or abnormal vital signs
• Petechial rash
• Respiratory distress
• Inconsolability or refusal to feed
• Vomiting or dehydration

Criteria for Discontinuing Antibiotics at 48 Hours

Antibiotics may be stopped ONLY if ALL of the following are met: 1, 2

• CSF analysis is normal or enterovirus-positive
• Urinalysis is negative
• All inflammatory markers are normal
• Blood and CSF cultures remain negative at 48 hours

Critical Pitfalls to Avoid

Never rely on clinical appearance alone - well-appearing infants can have serious bacterial infections including meningitis. 1, 2 This is the most dangerous error in managing febrile infants.

Never delay antibiotics while waiting for imaging, subspecialty consultation, or other tests. 1, 2

Never use bag collection for urine - only catheterization or suprapubic aspiration are acceptable. 1, 2, 4

Never defer lumbar puncture based solely on the infant appearing well or having viral symptoms, as concurrent bacterial meningitis is possible. 1

Symptomatic Management

• Acetaminophen may be given for comfort, not to normalize temperature 4
• Ensure adequate hydration to prevent dehydration 4
• The goal is infant comfort, not temperature normalization 4