Chylothorax is caused by an obstruction or injury to the chest duct. Its origin can be a trauma, a surgical intervention in the thorax, a thoracic cancer (in particular a lymphoma) or a congenital malformation (very rare).
1. Chylothorax: definition
Chylothorax is defined as a flow of chyle (a fluid from the lymphatic system) into the pleura, the space that surrounds the lungs (“Chylothorax, a radiological clarification”, published by the French language pneumology society). To understand better, you have to do a little anatomy. Lymphatic vessels are the part of the immune system that transports lymph throughout the body. The thoracic duct, the body’s major lymphatic vessel, carries chyle from the intestines to the blood. Chyle is made up of chylomicrons, which are long-chain fatty acids and cholesterol esters, but also immune cells (T lymphocytes, immunoglobulins), proteins, electrolytes, fat-soluble vitamins (a, D, E and K). At the level of the thorax, the thoracic duct also collects the lymph from the lymphatic vessels. A lesion of the thoracic duct can therefore cause a discharge of chyle which, if it infiltrates the pleura, causes a chylothorax.
2. Diagnosis of chylothorax
The doctor first conducts an anamnesis (collection of the patient’s symptoms and medical history), which makes him suspect chylothorax. He then requested imaging examinations and an analysis of the pleural fluid to confirm his diagnosis (“Diagnosis, support and treatment of chylothorax”, published by the Swiss medical journal). Imaging examinations generally consist of:
A puncture or drainage of the pleural fluid allows it to be analyzed, which informs the doctor about its composition and origin. Nowadays, lymphangiography or lymphoscintigraphy are less practiced.
3. Management of chylothorax
The treatment of chylothorax mainly depends on the pathology or its primary cause (“Chylothorax: Aetiology, diagnosis and therapeutic options”, published by Respiratory Medicine). The pulmonologist may consider draining the fluid or putting the patient on a low-fat, medium-chain triglyceride-rich diet. If these first-line treatments are not sufficient, surgical intervention under radiological control will be considered to seal the channel responsible for the flow (lymphangiography, percutaneous embolization, pleurodesis, pleuro-peritoneal shunt or ligature).
Sources:
French language pneumology society, Swiss medical journal, Respiratory Medicine
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