chylous

Chylous refers to chyle, the milky lymphatic fluid formed in the intestinal mucosa during fat digestion. Chyle is rich in triglycerides, chylomicrons, and immune cells. It is normally transported from the gut through lymphatic vessels to the bloodstream and does not normally accumulate in body cavities.

Chyle is produced in intestinal lacteals and drains through the lymphatic system, including the thoracic duct, into the venous circulation at the junction of the left subclavian and internal jugular veins. When lymphatic leakage occurs, chyle can accumulate in spaces such as the pleural cavity (chylothorax) or the peritoneal cavity (chylous ascites).

Chylous effusions have several causes. They most commonly result from disruption of lymphatic channels due to trauma or surgery, including oncologic procedures. Malignancy, especially lymphoma, is another frequent cause. Less common causes include congenital lymphatic abnormalities, infections, inflammatory disorders, and radiation therapy. The clinical presentation depends on the location and volume of the leak and may include dyspnea, abdominal distension, or persistent drainage from surgical sites.

Diagnosis is suggested by the milky or opaque appearance of the fluid and confirmed by laboratory analysis showing elevated triglycerides, usually above 110 mg/dL, and the presence of chylomicrons. Fluid triglyceride concentration, cholesterol levels, and lymphangiography can help identify the site of the leak.

Management focuses on treating the underlying cause and reducing lymph flow. Dietary modification with a medium-chain triglyceride diet or total parenteral nutrition can lessen chyle production. Pharmacologic options such as somatostatin analogs (e.g., octreotide) may reduce lymph flow. Persistent leaks may require interventional radiology procedures or surgery, including thoracic duct ligation or embolization, and drainage or pleurodesis for effusions. Prognosis depends on the underlying cause and response to therapy.