Chest
Volume 107, Issue 4, April 1995, Pages 1028-1031
Journal home page for Chest

Clinical Investigations: Infection
C-Reactive Protein in Simple Community-Acquired Pneumonia

https://doi.org/10.1378/chest.107.4.1028Get rights and content

Study objective

To assess whether C-reactive protein (CRP) is a sensitive marker of pneumonia and to evaluate whether it may be used as an index of treatment response.

Design

A retrospective casenote review was carried out on 40 patients admitted with simple community acquired pneumonia and 20 patients admitted with purulent bronchitis (infective exacerbations of chronic obstructive airways disease). Serum CRP levels, in addition to other traditional markers of infection, were measured in all patients on the first day. In 21 cases of pneumonia, a second CRP measurement was available after 3 to 7 days of antibiotic therapy.

Results

Temperature and WBC count showed considerable overlap between the pneumonia and bronchitic groups, whereas there was no overlap in serum levels of CRP. C-reactive protein levels were above 100 mg/L in all but two cases. In the bronchitic group only 7 out of 20 had levels above the normal range (<10 mg/L). Mean ± Standard Error of the Mean and lower/upper quartiles for CRP (mg/L) were as follows: pneumonia 217 ± 16 mg/L, 130/275; purulent bronchitis, 18 ± 3 mg/L, 10/18; [95% confidence interval (CI) for difference 153, 244 mg/L]. A CRP above 70 mg/L in pneumonia on day 1 occurred in association with a WBC count <12×109/L in 45% of cases and with a temperature <37.0°C in 32%. CRP levels fell to <100 mg/L in all cases of pneumonia after antibiotic treatment: pre-treatment 213 ± 21 mg/L ± 2, 138/270; posttreatment 31 ± 5 mg/L, 14/47; [95% CI for difference 141, 221 mg/L].

Conclusion

Serum CRP may be a useful adjunctive test in pneumonia, both in terms of distinguishing parenchymal from endobronchial infection, as well as being a marker of treatment response.

Section snippets

Patients and Methods

A retrospective study was performed using 40 random cases of simple community-acquired pneumonia in patients admitted to the respiratory unit. The cases were identified by a third party on the basis of the diagnosis on the discharge letter. The necessary information regarding physical signs, temperature, and investigations were extracted from the case notes. The presence of localizing chest signs (crackles or pleural rub) and new consolidation on the chest radiograph were required for

Results

Data are provided in the text in the following order: mean ± SEM, range, and lower/upper quartiles. The pneumonia group tended to be of a younger mean age than the COPD group, although this was not significant (p=0.19): pneumonia 64 ± 3 yr, 19–22, 53/76; purulent bronchitis 69 ± 2 yr, 50–85, 62/76 (95% CI for difference −3, 14 yr).

All cases of pneumonia clinically responded to antibiotic treatment and there were no fatalities. There was a considerable degree of overlap in both temperature and

Discussion

The results of the present study showed that CRP levels were considerably higher in patients with community-acquired pneumonia compared with those who had purulent bronchitis without pneumonia. If an arbitrary cut-off value of 100 mg/L is used, then in all but two cases (5%) of pneumonia, it is possible to separate patients with parenchymal lung sepsis from those with endobronchial infection. These findings are similar to previous data from Morley and Kushner4 who reported significantly higher

References (8)

There are more references available in the full text version of this article.

Cited by (98)

  • Urine Dipstick of Sputum for the Rapid Diagnosis of Community Acquired Pneumonia

    2018, Journal of the National Medical Association
    Citation Excerpt :

    However, the clinical picture may not be clear in the case of accompanying lung diseases or when the consolidation is not seen radiologically in the early stages and there are no other signs of infection, such as fever or leucocytosis. In the presence of such atypical clinical and radiological findings, it is difficult to diagnose pneumonia.9 For this reason, rapid diagnostic methods that can support clinical and radiological findings are being studied.

  • The role of biomarkers in low respiratory tract infections

    2012, European Journal of Internal Medicine
    Citation Excerpt :

    Literature data on PCT-guided antibiotic therapy for E-COPD have recently been reviewed by Tokman et al. [45]. In 1995, Smith RP et al. firstly suggested the use of CRP levels monitoring as a marker of treatment response in a small cohort of in-hospital CAP patients [46]. Similarly, a prospective hospital-based study further confirmed that, unlike tumor necrosis factor-α and interleukin-6, persistently high or rising levels of CRP were suggestive of treatment failure in 28 patients with suspected CAP [47].

View all citing articles on Scopus

This paper has been presented in abstract form as a spoken communication to the British Thoracic Society, Dublin, July 1993.

View full text