Table II.
Differential diagnosis of severe viral community-acquired pneumonia
| Influenza | Adenovirus | CMV | |
|---|---|---|---|
| Symptoms | |||
| Onset | Acute | Acute | Acute |
| Presentation | Acute/severe | Subacute/moderate | Subacute/moderate |
| Myalgias | + | ± | ± |
| Neck/back pain | + | − | − |
| Signs | |||
| Fever | + | + | + |
| Dry cough | + | ± | ± |
| Conjunctival suffusion | + | ± | − |
| Blood tinged sputum | + | − | − |
| Laboratory tests | |||
| CBC: | |||
| Leukocytosis | − | − | ± |
| Leukopenia | + | + | ± |
| Relative lymphopenia | + | + | ± |
| Atypical lymphocytosis | − | + | + |
| Thrombocytopenia | + | + | ± |
| Cold agglutinin titers (<1:64) | ± | ± | ± |
| Chest x-ray | |||
| No/minimal infiltrate (early <48 h) | + | + | + |
| Bilateral diffuse infiltrates (later >48 h) | + | ± | − |
| Focal infiltrates | −⁎ | + | − |
| Severe hypoxemia (A-a gradient >35) | + | ± | ± |
| Fluorescent respiratory viral panel | + | + | − |
| ↑ Influenza IgM titers | + | − | − |
| ↑ Adenoviral IgM titers | − | + | − |
| ↑ CMV IgM titers | − | − | + |
| + CMV PCR | − | − | ± |
| Diagnostic bronchoscopy | |||
| BAL cytology | − | − | − |
| TBB (viral inclusions) | + | + | + |
Ig, Immunoglobulin; PCR, polymerase chain reaction; CBC, complete blood count; CMV, cytomegalovirus; BAL, bronchoalveolar lavage; TBB, transbronchial biopsy.
Adapted from Cunha BA. Pneumonia essentials. 3rd edition. Jones & Bartlett, Sudbury, MA, 2009.
⁎
Only with coexistent S. aureus CAP.