Etiology | Clinical features | Radiographic features |
Bacteria (most commonly Streptococcus pneumoniae) | - Children of all ages
- Abrupt onset
- Ill-appearance
- Chills
- Moderate to severe respiratory distress
- Focal auscultatory findings
- Localized chest pain
- WBC count >15,000/microL (if obtained)
- Elevated acute phase reactants (if obtained)
| - Alveolar infiltrates
- Segmental consolidation
- Lobar consolidation
- "Round" pneumonia
- Pleural effusion/empyema
- Lung abscess
- Necrotizing pneumonia
- Pneumatocele
|
Atypical bacterial (Mycoplasma pneumoniae, Chlamydia pneumoniae) | - Children of all ages (most common in children >5 years)
- Abrupt onset with constitutional findings (malaise, myalgia, headache, rash, conjunctivitis, photophobia, sore throat)
- Gradually worsening nonproductive cough
- Wheezing
- Extrapulmonary manifestations or complications (eg, polymorphous mucocutaneous eruptions, hemolytic anemia, hepatitis, pancreatitis, myopericarditis, aseptic meningitis)
| - M. pneumoniae:
- Lobar or segmental consolidation (37%)
- Parahilar or peribronchial infiltrates (27%)
- Localized reticulonodular infiltrates (21%)
- Patchy infiltrates (15%)
|
Viral | - Usually children <5 years
- Gradual onset
- Preceding upper airway symptoms
- Nontoxic appearing
- Diffuse, bilateral auscultatory findings
- Wheezing
- May have associated rash (eg, measles, varicella)
| - Interstitial infiltrates
- Associated bronchiolitis:
- Patchy atelectasis
- Peribronchial infiltrations with air bronchograms
- Hyperinflation with flattening of the diaphragms
|
Afebrile pneumonia of infancy (most commonly Chlamydia trachomatis) | - Usually in infants 2 weeks to 4 months
- Insidious onset
- Tachypnea, diffuse crackles
- Rhinorrhea
- Staccato cough pattern
- Peripheral eosinophilia (if CBC obtained)
| - Hyperinflation with interstitial infiltrates
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Fungal | - Appropriate geographic or environmental exposure
| - Mediastinal or hilar adenopathy
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Mycobacterium tuberculosis | - Children of any age
- Chronic cough
- Constitutional symptoms
- Exposure history
| - Mediastinal or hilar adenopathy
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