Pseudochylothorax in pleural effusion due to coronary artery bypass surgery

Abstract

This study describes a 64-yr-old male with a chronic left pleural effusion following a coronary artery bypass 3 yrs earlier. On thoracocentesis, turbid fluid was obtained with crystals of cholesterol on microscopic examination, establishing the diagnosis of pseudochylothorax. The pleural fluid cholesterol level was 207 mg. dL-1 (5.36 mmol. L-1). This is the first report of pseudochylothorax in a chronic pleural effusion due to coronary artery bypass surgery. Eur Respir J 1999; 13: 1487±1488. Pseudochylothorax is a pleural effusion with a very high content of cholesterol [1]. It can occur when fluid has been present in the pleural space for a long time especially with fibrotic pleura [1, 2]. The three most common causes of pseudochylothorax are tuberculous pleural effusion, therapeutic pneumothorax, and chronic rheumatoid pleurisy [1±4], but it can develop with other diseases which cause extensive fibrosis of the pleura [1]. Chronic pleural ef-fusion and pleural thickening may occur following coronary artery bypass, but this procedure has not previously been described as a cause of pseudochylothorax. Case report A 64-year-old male with a past medical history of my-ocardial infarction and coronary artery bypass surgery was admitted to the authors' hospital because of a decompen-sation of congestive heart failure which resolved in a few days following conventional therapy. Chest radiographs during the admission showed an unchanging pleural effu-sion that occupied more than one-third of the left hemi-thorax. The patient was aware that he had a chronic pleural effusion after having undergone coronary artery bypass 3 yrs earlier at another hospital. The radiograph prior to surgery was normal and he had no history of previous pleural disease, tuberculosis, or rheumatoid arthritis. The cardiac surgeon followed the patient for 1 yr and informed him that he had a left pleural effusion which had not changed during this period. At that time, no thoraco-centesis or other diagnostic tests were performed. On admission to our hospital, a chest computed tomographic scan showed the large left pleural effusion with thickened pleura and a small right pleural effusion. Thoracocentesis was performed and turbid fluid was obtained. Examination for malignant cells was negative, as were stains and cultures for bacteria, mycobacteria and fungi. Pleural fluid analysis showed an exudative effusion with a cholesterol level of 207 mg. dL-1 (5.36 mmol. L-1) and triglycerides 81 mg. dL-1 (0.90 mmol. L-1). Crystals of cholesterol were seen on microscopic examination, confirming the diagnosis of pseu-dochylothorax. The patient declined to undergo pleural decortication. Discussion