The pathogenesis, etiology, and evaluation of. It is estimated that approximately 10 percent of exudative pleural effusions are eosinophilic 2,3,5. These data suggest that pleural fluid triglycerides are in the chyliform range in acute bacterial parapneumonic effusion and empyema, and higher levels may indicate severity of the disease process. Pleural fluid eosinophilia (PFE, also called eosinophilic pleural effusion) is defined as pleural fluid with a nucleated cell count containing more than 10 percent eosinophils 1-4. His chest x-ray revealed large bilateral pleural effusions but no lung masses or adjacent lymphadenopathy. Congestive heart failure is the most common cause of a pleural effusion, but there is a multitude of other causes, including lung trauma or lung cancer (in which effusion is experienced in roughly half of all cases). Pleural Fluid Clinical Summary A 54-year-old man with long-standing diabetes mellitus, chronic renal failure, and no previous history of malignancy presented with shortness of breath. When this happens, breathing can be impaired, sometimes significantly. The patient with the triglyceride level of 383 mg/dl in the pleural fluid subsequently developed bronchopleural fistula and the remainder recovered uneventfully. A pleural effusion is the accumulation of excess fluid in the pleural space. There are two main reasons fluid may collect in the pleural space: Fluid may accumulate in the pleural space because of an imbalance between the pressure within blood vesselswhich drives fluid out of blood vesselsand the amount of protein in bloodwhich keeps. Serum triglycerides were in the normal range in all patients. Pleural fluid analysis comprises a group of tests used to determine the cause. Latex agglutination tests were performed on the pleural fluid for the detection of bacterial antigens, and ELISA method was used to evaluate the serum for mycoplasma antibodies. All the patients were on antibiotics before admission. Pleural fluid from four patients (aged 3 - 7 years, mean 4 years), who were admitted to Winthrop-University Hospital with the diagnosis of parapneumonic effusion, was obtained by thoracentesis, and was evaluated for microbiological and biochemical parameters (data summarized in table below). Little is known about triglycerides in pleural fluid in acute parapneumonic effusion and empyema. Triglyceride levels, above 110 mg/dl, are also seen in pseudochylothorax, which occurs in patients with long standing pleural effusion with thickened pleura. The presence of triglycerides in the pleural fluid, above 110 mg/dl, is suggestive of chylothorax and the demonstration of chylomicrons in the fluid establishes the diagnosis of chylothorax.