Chyle is a fluid which is milky white in color and mainly contains fat molecules. Chyle is generated in intestines after fat digestion and is transported to the chest cavity by lymphatics. The lymphatics in the chest then dump the chyle into the vena cava and this lymph fluid is then delivered into the main blood stream for processing. There are several causes for leaking of chyle into the chest causing chylothorax which may include heart disease, cancer etc. Traumatic rupture of the thoracic duct (large lymphatics carrying chyle) is one of the causes of chylothorax in dogs and cats. In several studies, an idiopathic chylothorax has been found to be one of the most common causes of chylothorax. Accumulation of chyle in the chest causes pressure on the fragile lung tissue resulting in reduced insufflation and less oxygenation of body tissues thus causing difficulty breathing.
How is a Chylothoax diagnosed?
You, your family veterinarian, and Dr. Jha (Board certified Surgeon) will use multiple diagnostic modalities to diagnose your pet. You may notice a difficulty in breathing, exercise intolerance and coughing. Your primary care veterinarian will do a physical exam and X-rays to begin the diagnosis. A sample of the chest fluid will be taken during this visit to confirm the make-up of chyle. Dr. Jha and his team will also recommend that a CT scan of the lungs to be performed for surgical planning..
How is a Chylothoax treated?
Surgical treatment gives the best prognosis in pets suffering from this disease. Although a low fat diet and a medication known as Rutin may be tried prior to surgery to lessen the leakage of the chyle into the chest.
Ligation of thoracic duct: This is the main treatment performed to stop the leakage of chyle from the thoracic duct. During this procedure, a small window is made into the chest between the two ribs. The thoracic duct is tied either using an automatic stapler or a silk suture material. We also perform this surgery minimally invasively using thoracoscopy.
In many patients, three procedures are used to treat this disease which consist of:
- Ligation of thoracic duct
- Pericardial window
- Ablation of cisterna chyli
In 25% of patients this can be a frustrating disease with recurrence. These patients continue to leak a small to moderate amount of chyle into the chest even after performing ligation of the thoracic duct, pericardial window and ablation of the cisterna chyli. Dr. Jha and his team may place a permanent drain in the chest cavity with a smaller port hidden outside the chest but under the skin for intermittent drainage of chyle at home.