ORIGINAL ARTICLEPleural Fluid Characteristics of Chylothorax
Section snippets
PATIENTS AND METHODS
We conducted a computer-assisted search of the electronic medical records at Mayo Clinic's site in Rochester, MN, and identified 103 consecutive adults (≥18 years) with chylothorax diagnosed during the 10-year period from January 1, 1997, through December 31, 2006. We included only patients with chylomicrons present in the pleural fluid as demonstrated by lipoprotein analysis. Of these patients, 74 (72%) had biochemical data available for the purpose of classifying the pleural fluid as
Demographic and Clinical Features
The 37 men (50%) and 37 women (50%) had a median age of 61.5 years (range, 20-93 years). Pleural effusion was unilateral in 58 patients (78%). Of these 58 patients, the effusion involved the right hemithorax in 39 (67%) and the left hemithorax in 19 (33%). Pleural effusion was bilateral in the remaining 16 patients (22%).
Surgical procedures were the cause of chylothorax in 38 patients (51%). These procedures included thoracotomy with lung resection and mediastinal lymphadenectomy (16 patients),
DISCUSSION
In the current study, gross appearance of the fluid was not a sensitive diagnostic criterion in identifying chylothorax. Less than half of chylous pleural effusions (44%) had the classic milky appearance attributed to chylothorax. This finding likely relates to the variable lipid content of the effusion, a direct consequence of the nutritional status of the patient. In some cases, another factor may have contributed to the formation of pleural effusion (eg, surgical trauma). Gross appearance of
CONCLUSION
Chylothoraces may present with variable pleural fluid appearance and biochemical characteristics. Nonmilky appearance is a common presentation and may cause the diagnosis of chylothorax to be overlooked. Chylous effusions may be associated with a wide range of total protein and LDH values, sometimes resulting in a transudative character by currently used criteria. Because triglyceride levels also vary in patients with chylothorax, traditional triglyceride cutoff values used in excluding the
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