Clinical and Laboratory Findings in Patients With Acute Respiratory Symptoms That Suggest the Necessity of a Chest X-ray for Community-Acquired Pneumonia

Abstract

Background:Pneumonia is a common illness in all parts of the world and is considered as a major cause of death among all age groups. Nevertheless, only about 5% of patients referring to their primary care physicians with acute respiratory symptoms will develop pneumonia.Objectives:This study was performed to derive practical criteria for performing chest radiographs for the evaluation of community-acquired pneumonia (CAP).Patients and Methods:A total of 420 patients with acute respiratory symptoms and positive findings on chest radiograph were evaluated from December 2008 to December 2009. The subjects were referred to outpatient clinics or emergency departments of Birjand's medical university hospitals, Iran, and were enrolled as positive cases. A checklist was completed for each patient including their demographic information, clinical signs and symptoms (cough, sputum production, dyspnea, chest pain, fever, tachycardia, and tachypnea), abnormal findings in pulmonary auscultation and laboratory findings (erythrocyte sedimentation rate, C-reactive protein levels, and white blood cell count). An equal number of age-matched individuals with acute respiratory symptoms, but insignificant findings on chest radiography, were included as the control group. Finally, the diagnostic values of different findings were compared.Results:The data showed that vital signs and physical examination findings are useful screening parameters for predicting chest radiograph findings in outpatient settings. Therefore, by implementing a prediction rule, we would be able to determine which patients would benefit from a chest X-Ray (sensitivity, 94% and specificity, 57%).Conclusions:This study's findings suggest that requesting chest radiographs might not be necessary in patients with acute respiratory symptoms unless the vital signs and/or physical examination findings are abnormal. Considering the 94% sensitivity of this rule for predicting CAP, a chest radiograph is required for patients with unreliable follow-ups or moderate to high likelihood of morbidity if CAP is not initially detected.

The diagnostic accuracy of lung auscultation in adult patients with acute pulmonary pathologies: a meta-analysis

“…Table 2 shows a low diagnostic accuracy of auscultation for pneumonia in these patients. Supplementary Figure 5 demonstrates a higher sensitivity for the combination of different breath sounds, found by Ebrahimazedeh et al (decreased breath sounds, crackles, rhonchi), followed by crackles as a single breath sound (see Table 3) 36 .…”

“…pneumonia. Nine prospective observational studies and two case-control studies included patients with acute respiratory symptoms or with an expected pneumonia and compared auscultation with CXR for the detection of pneumonia [35][36][37][38][39][40][41][42][43][44][45] . Table 2 shows a low diagnostic accuracy of auscultation for pneumonia in these patients.…”

Signs and Symptoms That Rule out Community-Acquired Pneumonia in Outpatient Adults: A Systematic Review and Meta-Analysis

“…Those that were moderate risk were only included after consideration of their limitations. 6,14,16,17,20,21 Two were case control studies 16,21 but enrolled patients prospectively in a consecutive series, and a CXR was performed on each patient. In 1 study, 17 not all patients received the reference standard CXR; those with a low probability of CAP were randomized to receive one or not.…”

“…The remaining 9 studies reported the accuracy of 18 simple heuristics that predict a dichotomous outcome of CAP versus no CAP (Appendix B4). A CDR using the presence of normal vital signs to exclude CAP was the most common, appearing in 4 studies, 15,16,20,21 while a CDR using normal vital signs plus a normal pulmonary examination to exclude CAP appeared in 3 studies. 15,16,21 Fourteen CDRs have good sensitivities (above 75%) while 12 lacked specificity (below 60%).…”

“…A CDR using the presence of normal vital signs to exclude CAP was the most common, appearing in 4 studies, 15,16,20,21 while a CDR using normal vital signs plus a normal pulmonary examination to exclude CAP appeared in 3 studies. 15,16,21 Fourteen CDRs have good sensitivities (above 75%) while 12 lacked specificity (below 60%). The highest sensitivity was 100%, for a clinical decision tree that used CRP less than 10 g/mL or CRP 11 to 50 g/mL and absence of dyspnea or daily fever to exclude CAP.…”