From the Guidelines
**Chylothorax assessment should involve a comprehensive evaluation of clinical presentation, pleural fluid analysis, and imaging studies, with a focus on confirming the diagnosis through thoracentesis and pleural fluid analysis showing a milky appearance, triglyceride levels >110 mg/dL, and a cholesterol-to-triglyceride ratio <1, as recommended by the American College of Radiology 1.** The diagnosis of chylothorax is typically made based on the presence of chylomicrons in the pleural fluid, with objective diagnostic criteria including a pleural fluid triglyceride level > 110 mg/dL and a ratio of pleural fluid to serum triglyceride level of >1.0, and a ratio of pleural fluid to serum cholesterol level of <1.0 1.
Key Components of Assessment
- Clinical presentation: patients typically present with dyspnea, chest pain, and decreased breath sounds on the affected side
- Pleural fluid analysis: showing a milky appearance, triglyceride levels >110 mg/dL, and a cholesterol-to-triglyceride ratio <1
- Imaging studies: starting with chest X-ray to identify pleural effusion, followed by CT scan of the chest to evaluate for underlying causes such as malignancy or trauma
- Additional testing: complete blood count, comprehensive metabolic panel, and coagulation studies
- Evaluation of nutritional status: since chylothorax can lead to significant loss of proteins, lymphocytes, and fat-soluble vitamins
Imaging Studies
Imaging studies are essential in the assessment of chylothorax, with the American College of Radiology recommending the following rating scale for radiologic procedures:
- X-ray chest: usually appropriate (rating 8) 1
- Lymphangiography chest and abdomen: usually appropriate (rating 8) 1
- MRI chest and abdomen without IV contrast: may be appropriate (rating 6) 1
- CT chest and abdomen without IV contrast: may be appropriate (rating 5) 1 The most appropriate initial imaging study is a chest X-ray, followed by a CT scan of the chest, and potentially lymphangiography or lymphoscintigraphy to identify the site of lymphatic leakage 1.
From the Research
Chylothorax Assessment
- Chylothorax is a condition where lymphatic fluid (chyle) accumulates in the pleural cavity, often due to disruption of the thoracic duct or its tributaries 2.
- The management of chylothorax depends on the cause and may include dietary modification, drainage of the pleural space, and definitive intervention such as surgery or percutaneous lymphatic intervention 2.
Treatment Options
- Conservative treatment, including parenteral nutrition or a special diet, succeeds in 20% to 80% of cases 3.
- Surgical treatment, such as ligation of the thoracic duct, pleurodesis, or a pleuroperitoneal shunt, has success rates ranging from 25% to 95% 3.
- Interventional radiological treatments, such as percutaneous thoracic duct embolization or the percutaneous destruction of lymphatic vessels, succeed in about 70% of cases and lead to healing in up to 80% of cases 3.
- Octreotide, a long-acting somatostatin analogue, has been shown to be effective in the treatment of chylothorax, with dramatic resolution of pleural effusion and no relapse observed during follow-up 4, 5, 6.
Nutritional Support
- Patients with chylothorax are at high risk for malnourishment due to continuous loss of chyle, which impairs their nutritional status 4.
- Nutritional support may include a low-fat diet supplemented with intermediate-chain triglycerides (ICT), fat-free enteral nutrition, or parenteral nutrition 4.
- There is no consensus on the most appropriate nutritional support, and the literature is based on single cases or case series 4.