BENEFITING: American Veterinary Medical Foundation
If you have never heard of Canine Chylothorax, you are not alone. I first learned of it when my 3 year old lab mix, Harper Lee, was diagnosed with this debilitating disease. We rescued Harper when she was a year old. She was a timid dog at first, but once she warmed up to me, we became fast friends. Harper is always by my side, and eventually became my constant companion when I went for runs in the neighborhood, or on the beach. This past summer my friend and I took our dogs for a 5 mile hike along Vickery Creek. However, over the course of a month or so (begining in early October) I had noticed that Harper had begun having trouble breathing, and was struggling to take deep breaths. She had also lost her appetite and had stopped eating. One day my dad took Harper on his normal walk with her, a 3 mile route they had walked countless times before, when Harper was suddenly unable to walk any further. She had begun foamin at the mouth and gasping for air. My dad got her home and brought her to our vet. That day they x-rayed her to find her chest full of fluid. They ended up draining 1 liter of milky white fluid that had been surronding her lungs and heart. We followed out vets directions and put her on a prescrobed lowfat diet. She began eating, again, but a week later she struggling to breath again. This time they removed 1.5 liters of the fluid. We then began giving her Rutin, a medicine commonly used in such cases. However, she has had little improvement, and needs to be pumped ever other week. Our vet has said that she can no longer go on walks, runs, or hikes, until we see a long term improvement. Unfortunately, I found the chances of this are not the best. Harper's diagnosis with Chylothorax led me to research this is a rare, idiopathic medical condition that occurs in dogs, but can also occur in cats. In it's most basic terms, it is the accumulation of fluid in the chest cavity that puts pressure on the animals lungs and heart, impeading the animals ability to breathe. It develops when chyle, a fatty lymphatic fluid, accumulates in the chest cavity, outside the lungs (called the pleural space). Chyle normally empties from the intestinal lymphatics (which are lymph system vessels) into the veins in the chest cavity. Instead, in a dog (or cat) with chylothorax, the chyle is secreated into the area around the lungs and heart. Chylothorax remains a complicated condition that is poorly understood and difficult to treat. There are some methods currently being used to try to treat chylothorax. Non-surgical methods include pleural drainage, dietary management and vitamin supplementation, and pharmaceutical control. However, these methods do not permanently treat the condition. Although it may relieve the symptoms for a short time, it does not cure the disease. Drainage of the fluid is important for alleviating signs of respiratory distress. However, chest drainage alone only allows for temporary resolution of effusion. Long-term drainage of chyle from the thorax may lead to dehydration, hypoproteinemia, malnutrition, electrolyte disturbances, and possible immune deficiency. Long term medical management of chylothorax may lead to chronic inflammation causing restrictive pleuritis that can be a serious, life-threatening sequelae of chronic chylothorax. Dietary management includes the use of a low-fat diet to decrease flow through the thoracic duct, which in turn reduces the volume of effusion. However, studies have shown that the use of low fat-diet reduces the lipid content of the effusion but does not seem to effectively decrease the volume of effusion. There is no substantial, long term treatment for dogs (or cats) suffering from chylothorax. 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. Unfortunately, the surgical methods used do not hold the most promising success rates. In the dog, surgical treatment of chylothorax is most commonly done by ligation of the thoracic duct. Results of studies have shown that thoracic duct ligation in successful in 20-60% of dogs and cats with chylothorax. This is not a first-choice treatment method, mostly a last resort. Chylothorax remains a complicated condition that is poorly understood and difficult to treat. Although results of recent studies have improved our understanding of the pathophysiologic mechanism of the disease, treatment failure remains common. Additional research is needed to better delineate the pathophysiologic mechanism of idiopathic chylothorax and to improve treatment results.