-We recommend based on moderate quality evidence consideration of bacterial pneumonia in a patient with the following clinical symptoms and physical exam findings: fever, lower respiratory tract symptoms and focal auscultatory findings excluding wheezing.
No gold standard currently exists for the diagnosis of bacterial pneumonia, including CXR (Lynch, Bialy et al. 2010) limiting the methodology of studies attempting to develop prediction tools to link clinical symptoms with bacterial disease. The British Thoracic Society guideline recommends consideration of bacterial pneumonia in patients with persistent fever >38.5 with chest recession and raised respiratory rate, however, the quality evidence for this recommendation is low (Harris, Clark et al. 2011). The PIDS/IDSA guideline does not address clinical symptoms to diagnose bacterial pneumonia (Bradley, Byington et al. 2011).
Multiple primary studies have attempted to identify clinical symptoms associated with blinded radiologist CXR reading of bacterial pneumonia/infiltrate. Mathews et al performed a prospective cohort study on patients presenting to the ED with wheezing on physical exam who had a CXR performed for possible pneumonia (PNA) and found radiographic pneumonia in only 4.9% of patients and only 2% of patients with wheezing without fever (Mathews, Shah et al. 2009). Neuman et al, identified that the accuracy of physician’s clinical impression of PNA was high for patients presenting to the ED. Overall, patients perceived to be at the lowest risk for pneumonia (<5% prediction) had only 4.3% of CXR findings identified as definite pneumonia (95%CI, 2.9%-5.7%), while patients perceived to be a high risk for pneumonia (76-100% prediction), 30.6% (95%CI, 15.5%-45.6%) had definite and 52.8% (95% CI, 37.7%-70.3%) had probable or definite CXR findings. In support of Matthews finding, wheezing was a poor indicator of CXR PNA (definite pneumonia, 7.8%; probable or definite pneumonia, 12.5% (Neuman, Monuteaux et al. 2011). A second paper by Neuman et al, looked to associate history and physical exam findings with radiographic pneumonia. Results found that a history of chest pain, focal rales on auscultation, duration of fever and hypoxia on presentation to the ED were associated with CXR PNA, while tachypnea, retractions and grunting respirations were not (Neuman, Scully et al. 2010). Shah and colleagues evaluated the WHO definition of pneumonia and looked to correlate children with tachypnea and radiologic PNA. Overall, they found the use of tachypnea was associated with low sensitivity and specificity for the diagnosis of PNA (Shah, Bachur et al. 2010).
Two studies identified that pulse oximetry findings do not help differentiate bacterial pneumonia from other lower respiratory tract disease, specifically viral infections, however hypoxia may aid providers in identification of disease severity (Tanen and Trocinski 2002). Finally, the incidence of occult pneumonia in patients without lower respiratory tract findings was found to be 5.3% to 6.8% with an increased likelihood with increased duration of fever or leukocytosis (Murphy, van de Pol et al. 2007; Shah, Mathews et al. 2010). Based on the available literature, patients more likely to have bacterial pneumonia as compared to viral lower respiratory tract disease will have fever, specifically longer duration of fever, focal auscultatory findings, tachypnea and no wheezing on auscultation.
What clinical exam findings are more likely to be present with complicated CAP?
-We recommend based on low quality evidence consideration of complicated pneumonia in a patient with the following clinical symptoms or physical exam findings:
In a study performed in Utah evaluating complicated pneumonia, patients more likely to have effusion or empyema were older than 3 y/o and were found to have prolonged fever, greater than 7 days (Byington, Spencer et al. 2002; Schultz, Fan et al. 2004). Additionally, the PIDS/IDSA guideline identifies that prolonged fever and abdominal and chest pain have been associated with pneumonia complications with concerning physical exam findings including dullness to percussion, decreased/diminished breath sounds, change in quality of breath sounds and transmitted speech (Bradley, Byington et al. 2011).
Children initially felt to have uncomplicated bacterial CAP on adequate antibiotic therapy are expected to show signs of improvement within 48-72 hours (Bradley, Byington et al. 2011; Harris, Clark et al. 2011). For children that do not show this improvement, further investigation should be performed and complicated pneumonia should be considered. Our recommendation is to re-evaluate with a CXR in addition to clinical exam, vital signs and laboratory findings, for the presence of a clinically significant pleural effusion that would alter antibiotic choice and possible surgical management of the patient. We would also recommend consideration of alternative diagnosis including viral lower respiratory tract infection, foreign body aspiration, aspiration pneumonia, tumor or mass, tuberculosis or histoplasmosis or other uncommon lung infection. Additionally, consideration of an Infectious Diseases consult is recommended for a patient with concern for an infectious process that is not clinically improving.