Etiology of chylothorax in 203 patients.

Objectives: To characterize the etiology of chylothorax in patients encountered at a single tertiary referral center and to compare the findings with those from previous studies.

Patients And Methods: The medical records of all patients with chylothorax seen at the Mayo Clinic in Rochester, Minn, over a 21-year period, from January 1, 1980, to December 31, 2000, were retrospectively reviewed to ascertain the underlying cause of their condition.

Results: We identified 203 patients with chylothorax; 92 were females (male-female ratio, 1.21). The median age was 54.5 years (range, 21 weeks' gestation to 93 years). Dyspnea, the most common presenting symptom, occurred in 98 (56.6%) of 173 patients in whom initial symptoms were recorded, whereas 64 (37.0%) had no respiratory symptoms. Median duration of symptoms before diagnosis was 7.5 weeks (range, 1 day to 4.5 years). Causes of chylothorax included surgery or trauma in 101 patients (49.8%), various medical conditions in 89 (43.8%), and unknown in 13 (6.4%). Among surgical procedures, esophagectomy (29 patients) and surgery for congenital heart disease (28 patients) were the most common causes of chylothorax. Among medical conditions, lymphoma (23 patients), lymphatic disorders (19 patients), and chylous ascites (16 patients) were the most common causes.

Conclusions: Chylothorax has numerous causes. In contrast to previous studies, surgery or trauma was the most common cause of chylothorax at our institution, accounting for nearly 50% of cases. Lymphoma and other malignancies caused chylothorax in only 16.7% of cases. These numbers are possibly related to the high volume of cardiothoracic surgical procedures performed at our tertiary referral center.