7-Month-Old with Cough, Shortness of Breath, and CRP 262 mg/L
This infant has severe bacterial pneumonia requiring immediate hospitalization, blood cultures, chest radiography, and empiric intravenous antibiotics—the markedly elevated CRP of 262 mg/L strongly indicates bacterial infection rather than viral illness. 1, 2
Immediate Assessment and Diagnosis
Obtain pulse oximetry immediately to assess for hypoxemia (SpO2 <92-93%), which would indicate severe disease and guide oxygen therapy decisions. 3, 1
Perform posteroanterior and lateral chest radiographs to document pneumonia, assess severity, and identify complications such as parapneumonic effusions, necrotizing pneumonia, or lung abscess. 3, 1
Draw blood cultures before starting antibiotics, as they are positive in approximately 10% of children with bacterial pneumonia and 10-18% with empyema, and may be the only positive culture if pleural fluid is sterile. 3, 1
Obtain a complete blood count in the context of severe disease, though it cannot reliably distinguish bacterial from viral causes—interpret alongside clinical findings and imaging. 3, 1
Why This is Bacterial Pneumonia
The CRP of 262 mg/L is exceptionally high and diagnostic. Research from the PERCH study demonstrates that CRP ≥40 mg/L has 77% sensitivity for confirmed bacterial pneumonia versus only 17% for RSV pneumonia, with an area under the curve of 0.87. 2 CRP levels >100 mg/L substantially improve specificity for bacterial infection, and this infant's level of 262 mg/L far exceeds this threshold. 4, 2
While guidelines note that CRP cannot be the sole determinant to distinguish viral from bacterial pneumonia, this caveat applies to moderately elevated values (20-100 mg/L). 3, 5 In viral upper respiratory infections, CRP typically peaks at only 10-60 mg/L on days 2-4 of illness. 6 This infant's CRP of 262 mg/L is incompatible with uncomplicated viral infection. 4, 6
Hospitalization Criteria Met
This infant requires immediate hospital admission based on multiple criteria: 1
- Significantly elevated inflammatory markers indicating severe bacterial infection
- Age 7 months with shortness of breath suggesting respiratory distress
- Likely hypoxemia or tachypnea (assess immediately)
- High risk for complications including empyema given the extreme CRP elevation 3
Empiric Antibiotic Treatment
Start high-dose intravenous amoxicillin immediately as first-line therapy for bacterial pneumonia in children under 5 years, targeting Streptococcus pneumoniae as the most likely pathogen. 1, 5 If the infant appears toxic or has complications on imaging, consider adding coverage for Staphylococcus aureus or other resistant organisms based on local epidemiology. 3
Monitoring and Serial CRP Measurements
Serial CRP measurements are highly useful for monitoring treatment response in this clinical context. 3 CRP should decrease with appropriate antibiotic therapy, and persistently elevated or rising CRP suggests treatment failure, complications (empyema, abscess), or resistant organisms. 3, 7
Research in neonatal sepsis shows that serial CRP levels have 97-98% sensitivity for bacterial infection when measured over 24-48 hours, with negative predictive values >98%. 8, 7 In this case, the initial CRP is so markedly elevated that trending downward will confirm appropriate treatment response. 7
Critical Pitfalls to Avoid
Do not delay antibiotics while awaiting culture results—the extreme CRP elevation and clinical presentation mandate immediate empiric therapy. 1, 9 A normal CRP should never delay antibiotic coverage in suspected serious bacterial infection, but conversely, a CRP this elevated demands immediate action. 9
Do not assume viral bronchiolitis despite the infant's age—while children under 2 years have viral etiologies in up to 80% of respiratory infections, this infant's CRP of 262 mg/L excludes uncomplicated viral disease. 5, 6
Assess for complications including parapneumonic effusion or empyema, which are common with such severe inflammatory responses. 3 If pleural fluid is present on imaging, consider early drainage as significant effusions are uncommon in viral infections. 3
Expected Clinical Course
With appropriate antibiotic therapy, CRP should begin declining within 24-48 hours. 7 If CRP remains elevated or the infant fails to improve clinically within 48-72 hours, obtain CT chest with contrast to evaluate for complications such as loculated effusions, lung abscess, or necrotizing pneumonia. 3