Association of hypoalbuminemia with the presence and size of pleural effusion in children with pneumonia

OBJECTIVE. Hypoalbuminemia is a common finding in children with massive parapneumonic pleural effusion; however, its incidence and pathogenesis are unclear. The objective of this study was to assess the presence and severity of hypoalbuminemia in children with parapneumonic pleural effusion and to propose a possible pathophysiologic mechanism. METHODS. The clinical charts of patients who were hospitalized in a tertiary pediatric center with bacterial pneumonia complicated by pleural effusion were reviewed. The volume of pleural fluid was assessed semiquantitatively and categorized as small, moderate, or large. The lowest serum albumin level was recorded, and caloric intake and protein loss were evaluated. Findings were compared with age-and gender- matched children who had bacterial pneumonia without pleural effusion and with children who had acute illnesses other than pneumonia. RESULTS. Of the 50 patients in the study group, 15 (30%) had small effusions, 16 (32%) had moderate effusions, and 19 (38%) had large effusions. Moderate-to-severe hypoalbuminemia was found in 52% of the study group, 6% of the patients with pneumonia without pleural effusion, and none of the patients with other illnesses. Mean serum albumin level was lower in patients with large pleural effusions than in patients with small effusions (2.66 ± 0.37 vs 3.66 ± 0.47 g/dL). There was no evidence of albumin loss or significant malnutrition. Estimation of the amount of albumin in the drained pleural fluid suggested an albumin shift from blood to pleural fluid. CONCLUSIONS. Significant hypoalbuminemia is common in children with parapneumonic pleural effusion. Large effusions are associated with low serum albumin levels, which might be explained in part by a shift from blood to pleural fluid.