This came up in Question 10.2 from the second paper of 2013. The college presented the candidate with a picture of some creamy chest fluid, and invited them to reach the conclusion that this 75 year old man suffered some thoracic duct damage in the course of their elective oesophagectomy.

Causes of chylothorax

An excellent article from 2010 lists several causes of chylothorax beyond the immediately obvious "the surgeon did it". Sure, he just had an oesophagectomy, but the  surgery was a total high-five success; couldn't this chyle leak be caused by sarcoidosis?

In brief, the causes of chylothorax are as follows:

  • Malignancy
  • Iatrogenic
  • Traumatic
    • Thoracic knife or bullet wounds
    • Blunt thoracic trauma
    • Childbirth
    • Forceful emesis or cough
  • Associated with infection
    • Filiariasis
    • Tuberculosis
  • Associated with disease states:
    • Sarcoidosis
    • Haemangiomatosis or lymphangiomyomatosis
    • Amyloidosis
    • Retrosternal goitre
    • SVC obstruction
    • Transdiaphragmatic movement of chylous ascites

Diagnosis of chylothorax:

  • Chylomicron content of pleural fluid is the gold standard. Chylomicrons are large (~1000 nm)  lipid globules and they belong in chyle, and so to find them in pleural fluid is profoundly abnormal. Differential lipoprotein content of pleural drain fluid can be assessed by electrophoresis- the chylomicrons form a large discrete band on the gel. Studies of pleural fluid looking for other chacteristic features of chyle leak have used chylomicron presence as the unique identifying feature diagnostic of chyle.
    • A Sudan III stain for fat is a more rapidly available test than the gold standard electrophoresis; the dye colours only oil, and will reveal the pleural fluid to be chyle if brightly coloured chylomicrons can be identified on microscopy.
  • Other  pleural fluid features have also been suggested as diagnostic of chylothorax. These are not as reliable. The linked study followed the pleural fluid results of 74 patients with chylothorax.
    • Milky colour: only 44% of these patients had milky chest drain fluid
    • Protein and LDH were usually high, but varied wildly. In 14% of patients, Light's criteria would have declared the fluid a transudate.
    • Pleural fluid triglyceride level was high in most, but not all patients- again, 14% had a reasonably normal pleural triglyceride level.
    • Overall, authors of the abovelinked study had concluded that "the use of traditional triglyceride cutoff values used in excluding the presence of chylothorax may miss the diagnosis in fasting patients".
  • Fasting test and fat challenge is the answer to such concerns. Chylomicrons are only found in the circulation within 3 hours of eating; they disappear in the fasted state. Chyle transportation is maximal after a high fat meal. One is therefore able to test for a chyle leak by observing the chest drain output after some sort of "fat challenge", typically with ice cream.
  • CT and lymphangiography may be helpful but practically speaking this could be difficult.

Why not just leave it?

Sure, to reopen a chest full of chyle seems to be a distatestful admission of defeat, especially if it was your own surgical skill which caused it. Indeed, what are the arguments for aggressive repair? What are the consequences of chyle leak and chylothorax?


  • There is a serious mortality rate, reported up to 50%.
    • The chyle collection is not a benign resident of the chest caivity.
    • The overlying lung will collapse and become infected.
    • The chyle itself can become infected, and turn into an empyema.
  • Chyle is fat on its way to the systemic circulation. Loss of chyle into the chest drain will result in the loss of numerous useful substances:
    • Caloric intake will be impaired
    • Fluid loss will occur
    • Chyle is full of lymphocytes; the loss of lymphocytes will occur (and it is diffuclt to replenish them)
    • Fat-soluble vitamins will be depleted, and their replacement will be ineffective

Management of chylothorax


Fahimi, Hossein, et al. "Current management of postoperative chylothorax." The Annals of thoracic surgery 71.2 (2001): 448-450.

Fujita, Takeo, and Hiroyuki Daiko. "Efficacy and Predictor of Octreotide Treatment for Postoperative Chylothorax After Thoracic Esophagectomy." World Journal of Surgery (2014): 1-7.

Seriff, NATHAN S., et al. "Chylothorax: diagnosis by lipoprotein electrophoresis of serum and pleural fluid." Thorax 32.1 (1977): 98-100.

Hillerdal, G. "Chylothorax and pseudochylothorax." European Respiratory Journal 10.5 (1997): 1157-1162.

Shah, Rachit D., et al. "Postesophagectomy chylothorax: incidence, risk factors, and outcomes." The Annals of thoracic surgery 93.3 (2012): 897-904.

Merigliano, Stefano, et al. "Chylothorax complicating esophagectomy for cancer: a plea for early thoracic duct ligation." The Journal of thoracic and cardiovascular surgery 119.3 (2000): 453-457.

Valentine, Vincent G., and Thomas A. Raffin. "The management of chylothorax." CHEST Journal 102.2 (1992): 586-591.

Nair, Sukumaran K., Matus Petko, and Martin P. Hayward. "Aetiology and management of chylothorax in adults." European journal of cardio-thoracic surgery 32.2 (2007): 362-369.

Hashim, Sami A., et al. "Treatment of chyluria and chylothorax with medium-chain triglyceride." New England Journal of Medicine 270.15 (1964): 756-761.

Maldonado, Fabien, et al. "Pleural fluid characteristics of chylothorax." Mayo Clinic Proceedings. Vol. 84. No. 2. Elsevier, 2009.

Light, Richard W., et al. "Pleural effusions: the diagnostic separation of transudates and exudates." Annals of Internal Medicine 77.4 (1972): 507-513.

McGrath, Emmet E., Zoe Blades, and Paul B. Anderson. "Chylothorax: aetiology, diagnosis and therapeutic options." Respiratory medicine 104.1 (2010): 1-8.

Shah, Rachit D., et al. "Postesophagectomy chylothorax: incidence, risk factors, and outcomes." The Annals of thoracic surgery 93.3 (2012): 897-904.

Ngan, H., M. Fok, and J. Wong. "The role of lymphography in chylothorax following thoracic surgery." The British journal of radiology 61.731 (1988): 1032-1036.