C-reactive protein in lower respiratory tract infections

Introduction : C-reactive protein being an acute phase protein rises in pneumonia and may be helpful in differentiating patients with lung parenchymal infection from patients with infection sequestered to the bronchial tree. Methods : A prospective study was undertaken where 48 pneumonia patients and 35 patients of COPD with acute exacerbation were included. Serum CRP levels and other traditional markers of infection and chest x-ray were done on presentation. Results : The mean CRP was found to be 75.87±17.1mg/L in patients with pneumonia and 16.71±20.76mg/L in patients with COPD in acute exacerbation. A highly significant (p=0.0012) difference was found in the CRP values between the two groups using the 't' test. More than 70% of pneumonia patients had CRP value >50mg/L with less than 3% of COPD patients having the same. Conclusion : Serum CRP may be a useful adjunctive test in pneumonia patients in distinguishing endobronchial versus parenchymal infection. A CRP value of more than in 50mg/L favours pneumonia.