Chylothorax

Synonyms

Chylous effusion; Chylous hydrothorax; Chylopleura

Definition

Chylothorax is an accumulation of lymphatic fluid within the pleural space. The effusion has an elevated concentration of neutral emulsified fats with triglyceride levels over 110 mg/dL, a cell count typically greater than 1,000 cells/μL, which is comprised of usually greater than 80% lymphocytes. The accumulation is the result of a variety of pathophysiologic mechanisms that ultimately impair the function of the thoracic duct, through direct damage or obstruction. Chylothorax is therefore a common final pathway of a heterogeneous group of diseases. Radiographic findings are nonspecific with regard to other effusions, but are characterized by blunting of the costophrenic angle on upright radiography.

The most common causes of chylothorax include trauma to the thoracic duct and lymphoreticular malignancy, which, for the latter, may be the presenting sign. Chylothorax is also caused by solid malignancies, superior...