Diagnostic Approach for Bronchopneumonia in Children
Diagnose bronchopneumonia in children primarily through clinical assessment using age-specific respiratory rate thresholds and fever, supplemented by pulse oximetry in all hospitalized cases, while reserving chest radiography for moderate-to-severe cases and avoiding routine microbiological testing in outpatient settings. 1
Clinical Diagnostic Criteria
Age-Specific Indicators for Bacterial Pneumonia
For children aged up to 3 years, suspect bacterial pneumonia when all three features are present: 1
- Fever >38.5°C
- Chest recession (lower chest wall indrawing)
- Respiratory rate >50 breaths/min
For older children (>3 years), a history of difficulty breathing is more diagnostically helpful than specific clinical signs. 1
Key Clinical Pitfall to Avoid
If wheeze is present in a preschool child, primary bacterial pneumonia is unlikely, and you should consider viral bronchiolitis or reactive airway disease instead. 1 This distinction is critical to avoid unnecessary antibiotic use.
Respiratory Rate Assessment
Use WHO age-specific cutoffs for tachypnea: 1
- <2 months: ≥60 breaths/min
- 2-12 months: ≥50 breaths/min
- 12-59 months: ≥40 breaths/min
Important caveat: Respiratory rate measurement requires standardization and may need adjustment at high altitude, where reference ranges differ. 1
Essential Diagnostic Tests
Pulse Oximetry (Mandatory for All Hospitalized Children)
Perform pulse oximetry in every child admitted to hospital with pneumonia. 1 This provides objective severity assessment and guides oxygen therapy decisions. Oxygen saturation ≤92% indicates need for hospitalization and supplemental oxygen. 1
Chest Radiography (Selective Use)
Do NOT perform chest radiography routinely in children with mild uncomplicated acute lower respiratory tract infection. 1 This represents a major shift from historical practice and reduces unnecessary radiation exposure.
Reserve chest X-rays for: 1
- Moderate-to-severe pneumonia requiring hospitalization
- Cases not responding to initial therapy after 48 hours
- Suspected complications (pleural effusion, lobar collapse)
The British Thoracic Society emphasizes that radiographic findings are poor indicators of etiology, so imaging cannot reliably distinguish bacterial from viral causes. 1
Acute Phase Reactants (Not Recommended)
Do NOT routinely measure acute phase reactants (CRP, ESR, procalcitonin) as they do not distinguish between bacterial and viral infections in children. 1 This contradicts common practice but is based on evidence showing poor discriminatory value.
Microbiological Testing Strategy
Outpatient Setting
There is no indication for microbiological investigation of the child with pneumonia in the community. 1 Treat empirically based on age and clinical presentation.
Hospitalized Children
Blood cultures should be performed in all children suspected of having bacterial pneumonia, though yield is low (typically <10%). 1
Viral testing is strongly recommended: 1
- Nasopharyngeal aspirates from all children under 18 months should be sent for viral antigen detection (immunofluorescence) with or without viral culture 1
- Sensitive rapid tests for influenza and other respiratory viruses should be used in all hospitalized children, as positive results may decrease antibiotic use and guide antiviral therapy 1
- A positive influenza test eliminates the need for antibacterial therapy in the absence of clinical, laboratory, or radiographic findings suggesting bacterial coinfection 1
Sputum culture should be obtained in hospitalized children who can produce sputum (typically >5-6 years old). 1
Mycoplasma pneumoniae testing should be performed in children with signs and symptoms suspicious for atypical pneumonia to guide antibiotic selection. 1
Do NOT test for Chlamydophila pneumoniae as reliable and readily available diagnostic tests do not currently exist. 1
Urinary Antigen Tests
Urinary antigen detection tests are NOT recommended for diagnosis of pneumococcal pneumonia in children due to high false-positive rates from nasopharyngeal colonization. 1
Severity Assessment and Hospitalization Criteria
Infants
Admit if any of the following are present: 1
- Oxygen saturation <92% or cyanosis
- Respiratory rate >70 breaths/min
- Difficulty breathing
- Intermittent apnea or grunting
- Not feeding
- Family unable to provide appropriate observation
Older Children
Admit if any of the following are present: 1
- Oxygen saturation <92% or cyanosis
- Respiratory rate >50 breaths/min
- Difficulty breathing
- Grunting
- Signs of dehydration
- Family unable to provide appropriate observation
Monitoring for Complications
If a child remains pyrexial or unwell 48 hours after admission for pneumonia, parapneumonic effusion/empyema must be excluded. 1, 2 This is a critical decision point that determines whether conservative management can continue or intervention is needed.
Use ultrasound to confirm the presence of pleural fluid collection if suspected clinically or radiographically. 1, 2
Follow-Up Imaging
Follow-up chest radiography should only be performed after: 1
- Lobar collapse
- Apparent round pneumonia (concerning for abscess or other pathology)
- Continuing symptoms despite appropriate therapy
Routine follow-up imaging in uncomplicated cases that resolve clinically is unnecessary and exposes children to additional radiation.
Algorithmic Approach Summary
- Assess clinically using age-specific fever and respiratory rate criteria
- Check oxygen saturation (mandatory if considering hospitalization)
- Obtain chest X-ray only if moderate-severe disease or diagnostic uncertainty
- For hospitalized children: blood cultures, viral testing (especially <18 months), consider Mycoplasma testing if atypical features
- Reassess at 48 hours: if not improving, consider imaging for complications and broaden antibiotic coverage
- Reserve follow-up imaging for specific indications only
This streamlined approach avoids over-investigation while capturing clinically significant cases and complications. 1