Usefulness of various inflammatory markers to differentiate pulmonary edema from pneumonia

Background: Community-acquired pneumonia requiring hospitalization is a severe illness with high mortality, especially if the appropriate treatment is delayed. Sometimes diagnosis is difficult due to an equivocal clinical picture or chest film, or to accompanying diseases that mask or simulate pneumonia. Objectives: To assess the usefulness of certain inflammatory markers in differentiating pulmonary edema from pneumonia throughout the hospital stay in patients admitted for pneumonia or pulmonary edema of non-infectious origin and to monitor the response to treatment. Methods: The study group comprised 50 patients admitted for pneumonia, 50 admitted for pulmonary edema and 30 healthy individuals. Blood samples for determination of leukocyte count, erythrocyte sedimentation rate (ESR), fibrinogen, Creactive protein (CRP), albumin, sCD14 and oxidized fibrinogen were drawn upon admission, at 48 and 72 hours after admission, and at discharge from the intensive care unit. Results: The levels of sCD14 were similar in both patient groups but higher than control levels during the first 48 hours (P < 0.03). They decreased gradually with hospital stay. The concentration of oxidized fibrinogen was similar in both patient groups and significantly lower than that of the healthy control group throughout the hospitalization period. Conclusions: Oxidized fibrinogen and sCD14 are not reliable markers for the diagnosis of pneumonia, for its differential diagnosis from pulmonary edema, and for patient follow-up throughout hospitalization. The finding of elevated levels of oxidized fibrinogen in the group of healthy controls warrants further study to identify the factors responsible for altering fibrinogen oxidation. The other markers are more indicative.