Clinical Investigation
Admission Chest Radiograph Lacks Sensitivity in the Diagnosis of Community-Acquired Pneumonia

https://doi.org/10.1097/MAJ.0b013e31818ad805Get rights and content

Abstract

Introduction

The clinical and epidemiological significance of community-acquired pneumonia (CAP) with a chest radiograph demonstrating no parenchymal infiltrate has not been studied. We determined the percentage of patients with a clinical diagnosis of CAP who did not have radiographic opacifications and compared this group with patients with CAP and radiographic infiltrates.

Methods

Patients admitted with a diagnosis of CAP were identified. Clinical history, physical examination, laboratory studies, and microbiological cultures were reviewed in a random sample of 105 patients. Admission and subsequent chest radiographs were interpreted without knowledge of the clinical data.

Results

Twenty-one percent (22/105) of patients with a clinical diagnosis of CAP had negative chest radiographs at presentation. Demographic, clinical, and laboratory data were the same in both groups. Fifty-five percent of patients with initially negative chest radiographs who had follow-up studies developed an infiltrate within 48 hours.

Conclusions

In patients admitted with a clinical diagnosis of CAP, the initial chest radiograph lacks sensitivity and may not demonstrate parenchymal opacifications in 21% of patients. Moreover, greater than half of patients admitted with a negative chest radiograph will develop radiographic infiltrates within 48 hours. Further studies are needed to develop evidence-based criteria for the diagnosis of CAP.

Section snippets

Patient Selection

Patients with CAP admitted to the University Hospital at the University of Cincinnati Medical Center (an urban 450 bed academic medical center) were identified retrospectively by the ICD-9 codes (480.0–487.0) available through hospital information systems. Charts were reviewed to ensure that the final clinical diagnosis of CAP was made by the physician at discharge. The only inclusion criterion was the final clinical diagnosis as determined by the attending physician. Of 520 patients admitted

RESULTS

Twenty-one percent (22/105) of patients with a diagnosis of CAP had negative initial chest radiographs. Patients with negative chest radiographs were not different in age or gender when compared with those with positive radiographs (Table 1). Disease severity, as calculated by the PSI, was 75.1 on average for those with positive chest radiographs and 81.9 for those with negative initial studies (P = 0.28). The PSI was not able to be calculated due to HIV infection for 12 patients with positive

DISCUSSION

In this study, 21% of patients admitted with a clinical diagnosis of CAP had a negative initial chest radiograph. Similarly, Basi et al16 found 1/3 of patients admitted to Canadian hospitals and managed using a CAP pathway did not have chest radiograph findings indicative of pneumonia. Unlike most previous investigations of CAP, our study and the investigation by Basi et al16 used the actual clinical diagnosis as inclusion criteria. Additionally, when 2 expert thoracic radiologists reviewed 282

REFERENCES (27)

  • British Thoracic Society Standards of Care Committee

    BTS Guidelines for the Management of Community Acquired Pneumonia in Adults

    Thorax

    (2001)
  • MandellL.A. et al.

    Canadian guidelines for the initial management of community-acquired pneumonia: an evidence-based update by the Canadian Infectious Diseases Society and the Canadian Thoracic Society. The Canadian Community-Acquired Pneumonia Working Group

    Clin Infect Dis

    (2000)
  • RamirezJ.A. et al.

    Early switch from intravenous to oral antibiotics in hospitalized patients with bacteremic community-acquired Streptococcus pneumoniae pneumonia

    Arch Intern Med

    (2001)
  • Cited by (86)

    • Adults with symptoms of pneumonia: a prospective comparison of patients with and without infiltrates on chest radiography

      2023, Clinical Microbiology and Infection
      Citation Excerpt :

      Traditionally, guidelines have recommended diagnosing pneumonia in hospital settings with a chest x-ray (CXR) or other comparable radiological assessments [5–7]. However, the diagnostic sensitivity of a CXR is only 44 to 77% [8,9] and is frequently negative in the first couple of days in older patients with pneumonia [10]. Additionally, older patients more often have fewer and less specific symptoms [11,12].

    • Infection source hidden behind compression fracture

      2022, Visual Journal of Emergency Medicine
    • Time to antibiotic administration and patient outcomes in community-acquired pneumonia: results from a prospective cohort study

      2021, Clinical Microbiology and Infection
      Citation Excerpt :

      Finally, the very restrictive disease definition must also be mentioned as a limitation. Some CAP patients develop infiltrates at a later stage or have very discrete radiological changes [28]. These patients were not captured by our study.

    • Point-Of-Care Ultrasound for Lung Assessment in Patients With Severe Scoliosis and Chest Deformities: An Emergency Department Case Series

      2020, Journal of Emergency Medicine
      Citation Excerpt :

      Internationally accepted guidelines recommend that the diagnosis should be made based on clinical features, but it lacks specificity and may overlap with viral infections (14–16). Historically, CXR study has been the imaging modality of choice when clinical features alone are unreliable or in more severe cases, but it cannot be considered a gold standard because it lacks sensitivity and specificity (17,18). An important consideration is that radiographic examinations expose patients to harmful ionizing radiation during a time at which they are believed to be most at risk of harm (19).

    View all citing articles on Scopus
    View full text