Chylothorax

Excerpt

Chylothorax is the accumulation of chyle in the pleural cavity. Chyle is derived from the Greek word chylos, which means "juice." Chyle is the milky bodily fluid formed in the lacteal system of the intestine. Chylothorax can result from trauma, surgical complications, malignancies, or congenital abnormalities. This rare but serious condition was first described in the 17th century by Bartloet and has recently received special attention due to innovative management strategies yielding favorable outcomes.

Small- and medium-chain triglycerides consumed in the diet are easily broken down into free fatty acids by intestinal enzymes and absorbed into the portal circulation. However, the large molecules of complex long-chain triglycerides cannot be broken down by the intestinal lipases. Instead, they combine with phospholipids, cholesterol, and cholesterol esters to form chylomicrons in the jejunum. These large molecules are then absorbed into the lymphatic system of the small intestine to form chyle. The lymphatic drainage from the intestine joins with that from the lower extremities to form the thoracic duct system, which ultimately drains into the systemic circulation. If the integrity of the thoracic duct is breached, the milky, lipid-rich chyle leaks into the surrounding structures.

Chylothorax occurs when chyle leaks into the pleural cavity due to damage to the thoracic duct. With an average production of approximately 2.4 L/d, a considerable amount of chyle can quickly accumulate in the pleural cavity.

The management of chylothorax in patients largely depends on the underlying cause and typically includes dietary modification and drainage of the pleural space. Definitive interventions, whether surgical or percutaneous lymphatic procedures, should be considered for patients with persistently high volumes of chylous output or prolonged leaks to prevent complications such as malnutrition.