What is the initial approach for an infant presenting with fever to the emergency pediatric clinic?

Initial Approach to an Infant with Fever in the Emergency Pediatric Clinic

The initial approach to a febrile infant in the emergency pediatric clinic must be age-stratified, with all neonates (infants <28 days) requiring full sepsis evaluation and hospital admission for parenteral antibiotics regardless of clinical appearance. 1

Age-Based Assessment

Neonates (<28 days)

• All febrile neonates require a "full sepsis workup" including blood, urine, and cerebrospinal fluid cultures, and should be admitted for parenteral antibiotic therapy regardless of clinical appearance 1, 2
• Hypothermia may indicate serious infection in this age group and should be treated with the same concern as fever 3

Young Infants (29-90 days)

• Risk stratification is appropriate for this age group, with management guided by clinical evaluation and laboratory investigations 2
• Consider using validated approaches such as the "Step-by-Step" approach, which has demonstrated 92.0% sensitivity and 99.3% negative predictive value for ruling out invasive bacterial infections 4
• Lumbar puncture may be considered, though there are no definitive predictors that identify which well-appearing febrile infants require cerebrospinal fluid evaluation 3

Older Infants (>90 days)

• Clinical assessment can direct laboratory testing and treatment in most cases 2
• Urinary tract infections cause more than 90% of serious bacterial illness in this age group 5

Initial Clinical Evaluation

• Determine if the infant appears toxic or ill, as this significantly changes management - only 58% of infants with bacteremia or bacterial meningitis appear clinically ill 3, 6
• Verify fever with a rectal temperature measurement (defined as ≥38.0°C/100.4°F) 3
• Consider the impact of recent antipyretic use (within 4 hours) which may mask fever 6, 3
• Assess immunization status (fully, partially, or not immunized) 3
• Evaluate caregiver's ability to monitor the child and return for follow-up if needed 3

Focused Evaluation for Common Sources

Urinary Tract Infection

• For urine collection, catheterization is preferred over clean catch or bag specimens due to lower contamination rates 3
• Consider urinary tract infection in all febrile infants, as it represents the most common serious bacterial infection in children 5

Pneumonia

• Consider chest radiograph if the infant has cough, hypoxia, rales/crackles on auscultation, high fever (≥39°C/102.2°F), or fever duration >48 hours 3
• Avoid chest radiograph in infants with wheezing or high likelihood of bronchiolitis 3

Meningitis

• For infants aged 1-3 months, cerebrospinal fluid evaluation should be considered based on clinical presentation and laboratory findings 3
• Recognize that viral infections of the central nervous system may present with non-specific symptoms and altered mental status 1

Laboratory Testing

• In well-appearing infants 1-3 months old, laboratory testing should include complete blood count with differential, urinalysis, blood culture, and urine culture 3, 2
• Consider inflammatory markers such as C-reactive protein and procalcitonin, which have been validated in approaches like the "Step-by-Step" 4
• Remember that only 14% of febrile children 2-36 months of age have a confirmed pathogen identified 7

Common Pitfalls to Avoid

• Relying solely on clinical appearance - many infants with serious bacterial infections may appear well 3, 6
• Failing to consider the impact of recent antipyretic use on temperature 3
• Unnecessary radiographic studies in infants with likely viral illnesses 3
• Overlooking MRSA infections, which should be considered in all patients with pyoderma, severe pneumonia, and catheter-related sepsis 1
• Failing to consider HSV infection of the CNS when an infant has altered mental status 1

Management Decisions

• For well-appearing infants with likely viral illness who are older than 3 months, symptomatic care and close follow-up may be sufficient 3
• For infants with suspected bacterial infection, appropriate cultures should be obtained before initiating antibiotics 3
• Consider that viral infections can coexist with bacterial infections 3