What is the recommended evaluation and workup for a febrile child, including history, physical examination, red‑flag signs, laboratory and imaging studies, and antipyretic management?

Pediatric Fever Workup: Age-Stratified Approach

Age-Based Risk Stratification and Management

The evaluation and management of pediatric fever is fundamentally determined by the child's age, with neonates (0-28 days) requiring mandatory hospitalization and full sepsis workup, while older infants and children can be risk-stratified based on clinical appearance and specific criteria. 1

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Neonates (0-28 Days)

Mandatory Evaluation

• All febrile neonates require hospitalization and empirical antibiotics due to high risk of severe bacterial infection related to reduced activity of opsonins, macrophages, and neutrophils 1
• Complete sepsis evaluation is obligatory and includes: 1, 2
  • Blood culture (obtain before antibiotics) 2
  • Urine culture via catheterization (never bag collection) 1, 2
  • Lumbar puncture for CSF analysis and culture 2
  • Complete blood count with differential 2
  • Inflammatory markers (CRP, procalcitonin) 2
  • Chest radiograph if respiratory symptoms present 2

Empiric Antibiotic Therapy

• Initiate ampicillin and gentamicin immediately after cultures obtained 3
• Admit for hospital observation pending culture results 2
• Discontinue antibiotics in 24-36 hours if cultures negative and child clinically improved 1

Critical Pitfall

• Do not rely on physical examination alone in this age group—the threshold for full sepsis workup is appropriately low 2

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Young Infants (29-90 Days/1-3 Months)

Initial Assessment

• Rectal temperature ≥38.0°C (100.4°F) confirms fever 4, 1
• Recent antipyretic use may mask fever; do not ignore this history 5
• Clinical appearance alone is unreliable—58% of infants with bacteremia or bacterial meningitis appear well 4

Diagnostic Workup

• Urine culture via catheterization (bag specimens are unreliable) 1, 2
  • UTI is the most common serious bacterial infection (8-13% prevalence) 2
  • Higher risk with: female sex, fever >24 hours, temperature ≥39°C, uncircumcised males 1
• Blood culture and complete blood count with differential 2
• Lumbar puncture for CSF if infant does not meet low-risk criteria 4, 2
  • Mandatory if: complex convulsion, unduly drowsy/irritable, systemically ill, age <12 months (strongly consider if <18 months) 4
• Chest radiograph indicated if: 1, 5
  • Respiratory symptoms (cough, hypoxia, wheezing)
  • Temperature ≥39°C
  • WBC count >20,000/mm³
  • Fever >48 hours
• Inflammatory markers (CRP, procalcitonin) help risk-stratify 2

Empiric Antibiotics

• Ceftriaxone or cefotaxime for suspected serious bacterial infection 3
• Obtain cultures before antibiotic administration 2

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Older Infants and Children (3-24 Months)

Risk Stratification

• Red flag signs requiring immediate evaluation: 5
  • Cyanosis or poor peripheral circulation 3
  • Petechial rash 3
  • Inconsolability 3
  • Respiratory distress (retractions, grunting, nasal flaring, stridor) 5
  • Tachypnea (>42 breaths/min in 1-2 year olds) 5
  • Oxygen saturation ≤92% 1
  • Severe dehydration 1
  • Toxic or severely ill appearance 1

Selective Diagnostic Testing

• Urine culture via catheterization if: 1
  • Female
  • Fever >24 hours
  • Temperature ≥39°C
  • Uncircumcised male
  • No other source identified
• Chest radiograph if: 1, 5
  • Respiratory symptoms present
  • WBC >20,000/mm³ (occult pneumonia in up to 26% of cases)
  • Fever ≥39°C
  • Avoid in children with wheezing or high probability of bronchiolitis 1
• Blood culture and CBC if serious bacterial infection suspected 4

Empiric Antibiotics (if indicated)

• Cefixime, amoxicillin, or azithromycin 3
• Current prevalence of occult bacteremia is 1.5-2%, with 5-20% developing serious sequelae 2

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Antipyretic Management

Indications for Use

• Use antipyretics only when fever causes discomfort, difficulty sleeping, or feeding problems—not to normalize temperature 1, 5, 6
• Fever itself is beneficial in fighting infection and does not worsen illness course 6
• Response to antipyretics does NOT correlate with likelihood of serious bacterial infection and should never provide false reassurance 5

Medication Selection

• Paracetamol (acetaminophen) or ibuprofen only 1, 5
• Dose based on weight, not age 5
• Combined or alternating use is discouraged 1
• Ibuprofen contraindicated in varicella or dehydration 5
• Antipyretics do not prevent febrile seizures or vaccine-related adverse effects 5, 7

Physical Measures

• Fanning, cold bathing, and tepid sponging cause discomfort and are not recommended 4
• Ensure adequate fluid intake 4

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Discharge Criteria (Well-Appearing Children)

Safe discharge requires ALL of the following: 1

• Well-appearing clinical status
• All laboratory investigations negative or appropriately managed
• Normal oxygen saturation
• Adequate hydration
• Reliable caregivers with verbal and written instructions
• Guaranteed follow-up within 24 hours
• Clear return precautions provided

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Special Populations Requiring Lower Threshold for Intervention

• Immunocompromised children 5
• Premature infants 5
• Children with congenital abnormalities or chronic illness 5
• Parental or physician concern validated as indication of serious illness 3

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Key Clinical Pitfalls to Avoid

• Never assume normal clinical appearance rules out serious bacterial infection—many children with bacteremia or meningitis appear well 4, 1
• Do not use antipyretic response as reassurance 5
• Never obtain bag urine specimens—only catheterized samples are reliable 2
• Do not administer antibiotics before obtaining cultures 2
• Normal WBC count does not rule out bacterial infection, especially in neonates 2
• Avoid unnecessary imaging in probable viral illnesses 1
• Monitor activity level, reactivity, and feeding ability—not just temperature 5