A chylothorax is a rare entity that arises from a chyle leaking from the thoracic duct. The injury can occur anywhere along the thoracic duct. Chylothorax is associated with several complications: cardiorespiratory distress, nutritional and immunological impairment, and physiological derangements. Chyle leaking can be a very debilitating condition. After drainage, chyle is usually a milky white fluid, which contains chylomicrons, electrolytes, albumin, prothrombin, immunoglobulins, and lymphocytes (it is bacteriostatic). A total of 2.5L of chyle flows daily through the thoracic duct.
Surgery and trauma are the leading causes (49.8%), with cardiothoracic procedures being the main cause of iatrogenic injury to the thoracic duct. Malignancy, lymphatic disorders, and unknown causes (6.4%) are also possibilities. Penetrating trauma, blunt trauma, spinal fractures, or posterior rib fractures can cause chylothorax. A case of chylothorax after a stab was reported by Dr. Chido Nyatsambo et al. from South Africa in the International Journal of Surgery Case Reports (2023). A male patient resorted to a local clinic after being stabbed in the chest. The wound was sutured and the patient was sent home. (How was this possible in a country that is a worldwide reference for traumatic injuries?)
Five days later he resorted to the same healthcare facility due to dyspnea and was sent to the trauma center. A pleural effusion was diagnosed and drained. The milky fluid was sent to microbiology and biochemical analysis, excluding an empyema and confirming the chylothorax (triglyceride and chylomicron). The surgical team started a conservative approach, with total parenteral nutrition (TPN), medium-chain triglycerides, and octreotide. No antibiotics were used. In the following three days, there was a substantial decrease in the output (780 mL/day to 90 mL/day). Eight days after admission there was no drainage. The patient was then put just on a low-fat diet with medium-chain triglycerides. The resolution of the chylothorax was confirmed in a chest X-ray on day 10, and the drain was removed. No CT scan was ever considered since the patient was improving with the conservative treatment. In my opinion, this is a matter of debate. I would have performed a CT scan to evaluate the lung parenchyma, the pleural space and possible collections, and the thoracic vessels (it was a stab). Would it have changed something in this particular case? I do not know... But in a future case, I believe a CT scan is important to have.
The delayed presentation reported by the authors is a common presentation for chylothorax. In a low-volume leak, it can be asymptomatic, but in a high-volume leak, dyspnea and hypovolemic shock can be present. Chest X-ray shows a large pleural effusion. Interestingly, after drainage only 44% of patients present a milky white fluid. In that setting, biochemical analysis is necessary for the diagnosis of chylothorax:
triglycerides > 110 mg/dL
presence of chylomicrons
cholesterol < 200 mg/dL
Aside from the intercostal drainage, the conservative management of a chylothorax has the objective to decrease the volume of lymphatic flow: dietary modification (medium-chain triglycerides), fluid resuscitation, and somatostatin or octreotide. Some cases may require nil-per os and TPN. However, some authors advise this aggressive conservative approach as a first-line treatment.
If a patient has a drainage of > 500 mL/day for more than two weeks, will probably fail to resolve with conservative treatment. The authors present as surgical indications the following:
metabolic derangements and malnutrition (clinical evaluation)
> 1-1.5 L/day
> 1 L/day for five consecutive days
> 100 mL/day for two weeks
drain output unchanged for two weeks
According to Dr. Chido Nyatsambo et al., there are several surgical treatment options as well as interventional radiological treatment strategies available:
thoracic duct ligation
pleurodesis
pleurectomy
pleuroperitoneal shunt
percutaneous thoracic duct ligation
percutaneous needle disruption of lymphatic pathways
In sum, chylothorax is rare, and trauma is a possible cause. Surgeons must be aware of the common delayed presentation of this condition after a trauma. Additionally, surgeons must remember that chylothorax has a milky white fluid in only 44% of patients. Treatment mandates a constant regular clinical evaluation to decide whether the conservative treatment is working or whether a surgical or radiological intervention is going to be necessary. Chylothorax can be a very debilitating condition if not well treated.
Link to article:
Dr. Carlos Eduardo Costa Almeida
General Surgeon
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