ABSTRACT
A chylothorax and a cholesterol pleural effusion represent the two forms of lipid
effusions encountered. Traditionally, a lipid pleural effusion is characterized by
the presence of milky fluid. Although these two effusions often share a similar pleural
fluid appearance due to the high lipid concentration, they have major differences
in the pathogenesis, clinical presentation, diagnosis, predisposing conditions, and
management of these effusions. A chylothorax is defined by the presence of chyle in
the pleural space resulting from obstruction or disruption of the thoracic duct or
one of its major tributaries. A triglyceride concentration > 110 mg/dL is virtually
diagnostic, but the presence of chylomicrons confirms the diagnosis. However, a chylothorax
defined by these criteria represents a heterogeneous group of clinical entities. The
presence of chylomicrons or triglyceride levels > 110 mg/dL in a pleural effusion
should be considered evidence of chyle leakage of indeterminate clinical significance.
Many cases of a chylous effusion may be associated with other causes of pleural fluid
formation. In the case of an acute or chronic chylothorax due to recent or remote
thoracic duct injury, this assessment is essential, as surgical ligation of the thoracic
duct is often entertained. In other cases, especially lymphoma or chylous ascites,
treatment of the underlying condition is indicated regardless, and the assessment
of the response to treatment is a reasonable initial approach. In contrast, a cholesterol
effusion is typically the result of long-standing pleurisy with elevated cholesterol
levels in the pleural space; however, this paradigm has been challenged. Lung entrapment
with thickened parietal and visceral pleural membranes is the typical radiographic
findings of a cholesterol effusion. Most cases of cholesterol pleural effusions are
attributed to tuberculous or rheumatoid pleurisy. Decortication is the mainstay of
treatment for a cholesterol effusion in symptomatic patients with restrictive lung
function.
KEYWORDS
Chylothorax - cholesterol effusion - pseudochylothorax - review
REFERENCES
hugginjt@musc.edu
