A persistently elevated C-reactive protein level in pneumonia may indicate empyema

Coelho et al. [1] investigated the use of C-reactive protein (CRP) levels for monitoring of patients with severe community-acquired pneumonia (CAP). They found that patients without a decrease in CRP levels on treatment had an increased mortality compared to patients with a rapid fall of this marker. The authors did not discuss another important use of the analysis of the time course of CRP levels in CAP that applies to patients on both the intensive care unit (ICU) and the general paediatric ward. Empyema fluid has been identified as an important source of CRP in pneumonia [2]. Patients with empyema may have CRP levels of a similar magnitude as the non-survivors in Coelho’s study on admission [3]. Adults as well as children who develop empyema were shown to have persistently elevated CRP or a secondary rise of this parameter despite adequate antibiotic treatment [3,4]. A persistently elevated or rising CRP level in a patient on the ICU should, therefore, alert the clinician not only to a potentially poor prognosis but also prompt a reassessment of the patient with a chest X-ray and chest ultrasound for the presence of an empyema that may require surgical evacuation. Letter A persistently elevated C-reactive protein level in pneumonia may indicate empyema Michael Eisenhut