RESUMO
INTRODUCTION: The management of acute lower respiratory tract infections and, in particular, the decision whether or not to commence antibiotic therapy, still remains difficult in the absence of reliable clinical or radiological criteria allowing confident distinction between bacterial and viral infections. Numerous biomarkers have been developed to help the clinician in his/her diagnostic and therapeutic approach, but the role and significance of each has not been clearly defined. BACKGROUND: Though procalcitonin (PCT) or C-reactive protein (CRP) seem equal in helping the clinician to decide whether to commence antibiotic therapy or not during the course of an exacerbation of asthma or chronic obstructive pulmonary disease (COPD), PCT is currently the most useful biomarker to distinguish sepsis from other causes of inflammation and to determine the bacterial or viral origin of a pneumonia. OUTLOOK: The ability of PCT to reduce the global exposure to antibiotics remains uncertain and the results of randomised trials are contradictory. CONCLUSIONS: Prescription algorithms involving PCT may be used without increased risk for patients even though clinical signs of severity remain important. Changes in PCT also have a prognostic value in identifying those patients with unfavourable outcome.
