Medical management of chylothorax involves evacuation of chyle from the thorax, either with a tube placed in the chest or intermittent thoracentesis. If a tube is placed in your pet’s chest, they will need to be hospitalized. The purpose of thoracic fluid evacuation is to allow the lungs to fully expand, relieving any breathing difficulty or coughing, making your pet much more comfortable. Feeding your pet a low-fat diet has been recommended to reduce the fat content of chyle and; therefore, reduce the flow of chyle through the TD. However, based on previous reports, it is unlikely that a low-fat diet alone will reduce the volume of chyle flowing through the TD. An oral supplement called ‘rutin’ may be useful in pets with idiopathic chylothorax. Rutin is available over the counter at most specialty health food stores, and it is suspected that rutin stimulates protein breakdown and removal in lymphatic vessels. The efficacy of rutin in the treatment of chylothorax in veterinary patients has yet to be proven.
Surgical intervention for the treatment of idiopathic chylothorax in dogs and cats is often undertaken, as medical management is rarely successful in resolving this disease. The prolonged loss of chyle into the thoracic cavity can lead to a metabolically compromised state for your pet. Also, the prognosis for clinical improvement decreases if the inflammation of the lining of the lungs is present due to chronic chyle exposure. Should your pet need to undergo surgery for the treatment of chylothorax, you should inquire about a referral to an ACVS board-certified veterinary surgeon.
The most commonly performed surgical technique for resolving chylothorax is thoracic duct ligation (TDL). The purpose of this procedure is to promote new lymphatic connections to the venous system in the abdomen by preventing chyle flow into the TD. This will effectively prevent leakage of chyle from the TD into the thoracic cavity. Recently, TDL has been combined with the removal of the lining of the heart (pericardiectomy), which has resulted in higher success rates compared to TDL alone. Also, a tube will be placed in the chest that can be aspirated post-operatively. Some veterinary surgeons will also perform abdominal surgery to allow for the injection of contrast material into an intestinal lymphatic vessel or lymph node to allow for the imaging of TD anatomy and confirm TDL after surgery (lymphangiography, Figure 2).
Another technique that has shown promise in the surgical treatment of chylothorax is the removal of the cisterna chyli (CCA). The cisterna chyli is a reservoir of lymphatic fluid that resides in the abdomen. CCA destroys this reservoir and allows the body to create alternative pathways for the lymph fluid to enter the bloodstream, thereby relieving pressure on the thoracic duct.
Video-assisted thoracoscopy is a minimally invasive alternative to thoracic surgery and has been used to perform TDL, pericardiectomy, and CCA in dogs. Recently, minimally invasive techniques for performing lymphangiography have also been described and can significantly reduce the time required to perform lymphangiography and alleviate the need for abdominal surgery.
Surgery for chylothorax may be time-consuming, and your pet is at an increased anaesthetic risk as they are likely metabolically compromised. Complications can include haemorrhage, infection, damage to the nerves that control the diaphragm, and persistent accumulation of fluid within the chest.