Roberts ME, Rahman NM, Maskell NA, et al; BTS Pleural Guideline Development Group. British Thoracic Society Guideline for pleural disease. Thorax. 2023 Jul;78(Suppl 3):s1-s42. doi: 10.1136/thorax-2022-219784. PMID: 37433578.
Feller-Kopman DJ, Reddy CB, DeCamp MM, et al. Management of Malignant Pleural Effusions. An Official ATS/STS/STR Clinical Practice Guideline. Am J Respir Crit Care Med. 2018 Oct 1;198(7):839-849. doi: 10.1164/rccm.201807-1415ST. PMID: 30272503.
Hooper C, Lee YC, Maskell N; BTS Pleural Guideline Group. Investigation of a unilateral pleural effusion in adults: British Thoracic Society Pleural Disease Guideline 2010. Thorax. 2010 Aug;65 Suppl 2:ii4-17. doi: 10.1136/thx.2010.136978. PMID: 20696692.
Also see Pleural Effusion.
DefinitionTop
Chylothorax is a pleural effusion caused by the leakage of lymphatic fluid into the pleural space from a ruptured thoracic duct or obstruction of the lymphatic vessels.
Causes: Malignancy (most commonly lymphoma or metastases of other cancers); injury, including surgery to the thoracic duct (particularly of the esophagus), chest trauma, sometimes catheterization of the superior vena cava; lymphangioleiomyomatosis; obstruction of a vena cava; amyloidosis; tuberculosis.
DiagnosisTop
Diagnosis is made on the basis of pleural fluid analysis. The fluid is milky-white and odorless and contains chylomicrons. The level of triglycerides is usually >1.24 mmol/L (110 mg/dL), no cholesterol crystals are present, and the level of cholesterol is <2.59 mmol/L (100 mg/dL).
Chylothorax has to be differentiated from pseudochylothorax, which occurs very rarely and is a result of the accumulation of cholesterol in a chronic pleural effusion. Usually, it develops in the course of a chronic pleural effusion, such as in tuberculosis or rheumatoid arthritis. The pleural fluid in pseudochylothorax has the same appearance as in chylothorax, but the level of cholesterol is >5.18 mmol/L (200 mg/dL), cholesterol crystals are present, and the level of triglycerides is usually <0.56 mmol/L (50 mg/dL).
TreatmentTop
Treatment includes pleural drainage and management of the underlying disturbances. Evaluation by a dietitian and instructions on a high-protein, low-fat (<10 g/d) diet are recommended. Total parenteral nutrition to reduce lymph production and close the fistula between the lymph vessel and the pleural space can also be considered if oral therapy is insufficient. Somatostatin and octreotide can be used as adjunctive therapies. In two-thirds of patients chylothorax resolves after 12 to 14 days. A constant lymph outflow >500 mL/d is an indication for surgical treatment.