The discriminative value of C-reactive protein levels in distinguishing between bacterial and viral pneumonia in children
Lala, Sanjay Govind
Background: CRP testing is routinely performed on children admitted to the Chris Hani-Baragwanath Hospital (Soweto, Johannesburg) with pneumonia. The CRP is used to distinguish between bacterial and viral pneumonia, assisting the clinician to judiciously prescribe antibiotics. Objectives: 1. To evaluate whether the initial CRP measurement discriminates between bacterial and viral pneumonia. 2. To evaluate the effect of HIV infection on CRP responses in children with pneumonia. 3. To perform a costs analysis of routine CRP measurements in childhood pneumonia. Design: Retrospective review of case records. Results: This study analysed 570 children with pneumonia who were catergorised into four aetiological groups- 55 children had bacterial pneumonia, 145 viral pneumonia, 11 mixed pneumonia and in 359 children the aetiology was unknown. 244 (42.8%) children were co-infected with HIV and 186 (32.6%) children were malnourished. The median CRP value was significantly higher in bacterial pneumonia than in viral pneumonia or pneumonia of unknown aetiology (P <0.0001, Median test). Threshold CRP values of >10mg/L could distinguish between bacterial and viral pneumonia (P=0.0009, Fishers exact test). However, in HIV uninfected children, receiver-operating characteristic (ROC) curve plots showed that only 80% of bacterial infections could be predicted using threshold CRP values. A LHP value >10mg/L predicted all cases of bacterial pneumonia in HIV infected childvsn, HIV infection did not affect CRP responses in children suffering from bacterial and/or viral pneumonia. Costs analysis suggests that routine CRP testing is expensive and outweighs the savings accrued by sparing the use of antibiotics in viral pneumonw. Conclusions: In HIV uninfected children, the initial CRP does not detect 20% of children with bacterial pneumonia. In HIV infected children, other studies are needed to confirm whether a CRP value >10mg/L predicts all cases of bacterial pneumonia, Routine CRP testing is not recommended in children with pneumonia.