Chyle is a milky bodily fluid consisting of lymph and emulsified fats, or free fatty acids (FFAs).
Chyle is formed in the small intestine during digestion of fatty foods, and taken up by lymph vessels specifically known as lacteals.
The lipids in the chyle are colloidally suspended in chylomicrons.
It has characteristic milky appearance.
A chyle fistula occurs when there is a defect(s) of lymphatic vessel(s) that results in leakage of lymphatic fluid, typically accumulating in the thoracic (pleural) or abdominal (peritoneal) cavities.
This process leads to a chylous pleural effusion (chylothorax) or chylous ascites, respectively.
Diagnosis of a chyle collection may be accomplished by analysis of pleural/peritoneal fluid. Identifying the source.
Localizing the lymphatic defect may be accomplished with lymphangiography.
Lymphangiography may occasionally have a therapeutic effect of resolving the leak, secondary to a sclerosant effect of the lymphangiography contrast.
The treatment of chyle fistulae relies upon either decreased production of lymphatic fluid to allow for healing of lymphatic defect(s) or permanent diversion of lymphatic fluid away from lymphatic defect(s).
Decreased production of lymphatic fluid may be accomplished by dietary restriction, replacement of oral intake with total parenteral nutrition), by the medications octreotide (a synthetic, and orlistat, a lipase inhibitor that decreases absorption of dietary fats.
Permanent diversion of lymphatic fluid may be accomplished by thoracic duct embolization or by thoracic duct ligation.