Early occurrence of chylothorax related to thoracic irradiation and concomitant chemotherapy

Clinical approach and review of causes of a chylothorax

A chylothorax, also known as chylous pleural effusion, is an uncommon cause of pleural effusion with a wide differential diagnosis characterized by the accumulation of bacteriostatic chyle in the pleural space. The pleural fluid will have either or both triglycerides >110 mg/dL and the presence of chylomicrons. It may be encountered following a surgical intervention, usually in the chest, or underlying disease process. Management of a chylothorax requires a multidisciplinary approach employing medical therapy and possibly surgical intervention for post-operative patients and patients who have failed medical therapy. In this review, we aim to discuss the anatomy, fluid characteristics, etiology, and approach to the diagnosis of a chylothorax.

Late-onset chylothorax during chemotherapy after lobectomy for lung cancer: A case report and review of the literature

RATIONALE

Chylothorax is usually diagnosed within a few days after lobectomy. Late-onset chylothorax following trauma or thoracic surgery is rare but potentially lethal, lacking reliable preventive methods.

PATIENT CONCERNS

A 54-year-old male patient complained of dyspnea during adjuvant chemotherapy on the 35th postoperative day after right middle lobectomy and systemic lymph node dissection (SLND) for lung cancer. His computed tomography indicated massive pleural effusion filling in the right chest cavity.

DIAGNOSES

The patient was primarily diagnosed as late-onset chylothorax, without definite evidence to exclude spontaneous chylous leakage.

INTERVENTIONS

Uniportal video-assisted thoracoscopic thoracic duct ligation (TDL) was performed for him, as conservative treatment using octreotide with fat-free diet turned out to be ineffective.

OUTCOMES

His pleural effusion was gradually diminished after reoperation, and the patient was discharged 9 days after TDL.

LESSONS

Postoperative late-onset or spontaneous chylothorax should be kept in mind after pulmonary resection and SLND, and the exclusion of chylous leakage could be considered as a precondition of chest tube removal.

Chylothorax: diagnostic approach

PURPOSE OF REVIEW

This review evaluates recent research findings and proposes an up-to-date diagnostic approach for patients with suspected chylothorax.

RECENT FINDINGS

Typically, chylothorax is a milky exudate with high triglyceride content (>110 mg/dl). However, milky appearance is not always the case and triglyceride levels can be less than 110 mg/dl, especially in fasting or malnourished patients. Transudative chylothoraces have been reported when cirrhosis, nephrosis or heart failure co-exist. In addition, although the vast majority of the white blood cells in chyle are lymphocytes, chylothoraces can be neutrophilic, especially the postsurgical ones.

SUMMARY

Chylothorax is the accumulation of chyle into the pleural cavity usually due to thoracic duct leak and should be suspected not only in patients with milky effusions but also in the presence of certain co-morbidities or history of chest/neck trauma. Fluid triglycerides more than 110 mg/dl or less than 50 mg/dl virtually establish or exclude the diagnosis, respectively; ambiguous cases with values 50-110 mg/dl require lipoprotein analysis for the demonstration of chylomicrons. In fasting or malnourished patients lipoprotein analysis is suggested even with triglycerides less than 50 mg/dl. Typical pleural fluid in chylothorax is a lymphocytic exudate with low lactate dehydrogenase; atypical fluid characteristics (i.e. transudative nature, neutrophil-predominance or high lactate dehydrogenase) may be a sign of additional causes of pleural fluid accumulation.