What is the initial approach to a fever workup in pediatric patients?

Initial Approach to Fever Workup in Pediatric Patients

The initial approach to fever workup in pediatric patients should be age-stratified, with special attention to neonates and infants under 3 months who require more aggressive evaluation due to their higher risk of serious bacterial infection. 1

Definition and Initial Assessment

• Fever is defined as a temperature of ≥38°C/100.4°F, with rectal temperature being the most accurate method for neonates and young children, while oral temperature is preferred in older, cooperative patients 1
• Verify the accuracy of home temperature measurements and document a rectal temperature in the clinical setting for infants and young children 2
• Determine if the child appears toxic or ill, as this significantly changes management - only 58% of infants with bacteremia or bacterial meningitis appear clinically ill 2
• Assess for hypothermia or normal temperature despite serious infection, especially if antipyretics were used in the previous 4 hours 2

Age-Stratified Approach

Neonates (0-28 days)

• Neonates with fever should always be hospitalized due to elevated risk of serious bacterial infection 3
• Complete evaluation includes:
  • Blood culture
  • Complete blood count with differential
  • Urinalysis and urine culture (via catheterization)
  • Lumbar puncture
  • Empiric antibiotic therapy 1, 2

Young Infants (29-90 days)

• Infants 29-90 days old are at high risk of bacterial infections due to exposure to bacterial pathogens and lack of vaccine-based immunity 1
• Evaluation includes:
  • Blood culture
  • Complete blood count with differential
  • Urinalysis and urine culture
  • Inflammatory markers (CRP, ESR)
  • Consider lumbar puncture based on clinical assessment 1, 2
• Hospital admission is often recommended, though low-risk infants may be managed as outpatients with close follow-up 2, 4

Children >3 months

• About 75% of well-appearing children with fever without source will have self-limited viral infections 1
• Initial evaluation includes:
  • Complete blood count with differential
  • Urinalysis and urine culture (especially in children <2 years)
  • Inflammatory markers (CRP, ESR) 2
• Consider chest radiograph if the child has cough, hypoxia, rales/crackles on auscultation, high fever (≥39°C/102.2°F), or fever duration >48 hours 2

Focused Evaluation for Common Sources

Urinary Tract Infection

• UTIs cause more than 90% of serious bacterial illness in children, with younger children having higher incidence 4
• For urine collection, catheterization is preferred over clean catch or bag specimens due to lower contamination rates 2

Pneumonia

• The prevalence of pneumonia in febrile infants is low (approximately 1-3%) 1
• Avoid chest radiograph in children with wheezing or high likelihood of bronchiolitis 2

Meningitis

• Lumbar puncture should be considered in neonates and young infants 1
• For children >3 months, lumbar puncture is generally not required unless there are specific signs or symptoms suggesting meningitis 2

Special Considerations

Neutropenic Fever in Cancer Patients

• Patients with cancer and neutropenia require immediate evaluation and broad-spectrum antibiotics 1
• Risk stratification into high and low risk is recommended 1
• Blood cultures should be obtained from all lumens of central venous catheters 1

Multisystem Inflammatory Syndrome in Children (MIS-C)

• Consider MIS-C in children with persistent fever, epidemiologic link to SARS-CoV-2, and suggestive clinical symptoms 1
• Initial screening includes CBC with differential, CMP, ESR, CRP, and testing for SARS-CoV-2 1
• Further evaluation is indicated for children with elevated inflammatory markers and concerning clinical features 1

Common Pitfalls to Avoid

• Relying solely on clinical appearance - many children with serious bacterial infections may appear well 2
• Failing to consider the impact of recent antipyretic use on temperature 2
• Unnecessary radiographic studies in children with likely viral illnesses 2
• Focusing only on treating the fever rather than identifying and addressing the underlying cause 5

Management Approach

• For well-appearing children with likely viral illness, symptomatic care and close follow-up may be sufficient 2
• For children with suspected bacterial infection, appropriate cultures should be obtained before initiating antibiotics 2
• Use of antipyretics (acetaminophen or ibuprofen) is recommended only when fever is associated with discomfort, not routinely for all fevers 3, 5