What is chylothorax and how might it appear in drainage?

• A. Chylothorax is a bacterial infection of the pleural space.
• B. Chylothorax is lymphatic fluid accumulating in the pleural space; drainage is often milky white and may require dietary modifications.
• C. Chylothorax is air in the pleural space causing pneumothorax.
• D. Chylothorax is clear plasma leakage from capillaries.

Answer: (B)

Chylothorax is the accumulation of chyle, a lymphatic fluid rich in dietary fats, in the pleural space, usually from injury or obstruction of the thoracic duct during surgery or trauma. In drainage, the fluid is typically milky white or opalescent after meals because it contains chylomicrons from fat absorption. Management centers on reducing chyle flow with dietary changes—most often a fat-restricted diet using medium‑chain triglycerides, since MCTs are absorbed directly into the portal system and bypass the lymphatics—and may require total parenteral nutrition if needed. If the leak persists, procedures to address the thoracic duct may be considered. This picture is distinct from a bacterial empyema, air in the pleural space causing pneumothorax, or clear plasma leakage, which would not present with a milky, lipid-rich drainage.