Treatment In-depth
                                                                                
Treatment of chylothorax may be divided into either medical management or surgical treatment. Note that some animals do resolve the condition on their own, probably because they reroute the chyle into alternate lymphatics and blood vessels in their abdomen.

The initial concern in treating your pet will be to improve his ability to breathe. Your veterinarian will generally remove the fluid in your pet's chest cavity using a needle. Occasionally, sedation or anesthesia will be required but a chest tap can often be performed with the animal awake. Depending on the degree of difficulty that your animal is experiencing breathing, oxygen therapy may be required. Further treatment will depend on whether an underlying disease was identified or whether the condition is thought to be idiopathic (no underlying disease found).

Medical management is usually considered first for the treatment of idiopathic chylothorax. It usually consists of intermittent chest taps to allow your pet to breathe more easily, dietary modification and drug therapy. If medical management is unsuccessful, surgery may be considered.

Medical Management

Intermittent thoracentesis (chest taps) usually are performed whenever your pet begins to have increased difficulty breathing. When medical therapy is successful, the intervals between taps usually increases because the fluid accumulates more slowly or is more effectively absorbed from the chest cavity into the bloodstream.

A commercial low-fat diet may be helpful. If your pet will not eat these diets, ask your veterinarian for a recipe for a homemade low-fat diet. Homemade diets are often more palatable than the commercial diets, but care must be taken to ensure that they are nutritionally complete.

Benzopyrone drugs such as Rutin may be recommended. These drugs are experimental, but may help your pet absorb the chyle until it resolves spontaneously. Rutin is generally given three times a day by mouth. The tablets may be crushed and put in the food, but care must be taken to ensure that your pet actually ingests the medication.

Surgical Therapy

Thoracic duct ligation is the most successful surgical therapy for idiopathic chylothorax. This surgery is most likely to be successful if mesenteric lymphangiography, which is a dye study that shows the thoracic duct and its branches, is performed in conjunction with the duct ligation. When these procedures are performed, your pet will have two incisions – one behind the last rib and one in between several of the last ribs. A chest tube is placed after surgery to monitor the amount of fluid that is produced. This surgery is not always successful; some animals continue to produce chyle and others continue to produce a clear fluid after surgery. The surgery is most likely to be successful if it is performed by someone experienced with this procedure. Your veterinarian will likely refer you to a specialist for the surgery.

If thoracic duct ligation is not successful, a pleuroperitoneal shunt may be placed. The pump lies under the skin and requires that you compress it in order to empty the chest fluid into the abdomen or the bloodstream. These pumps are expensive and are usually considered only as a last resort.

If an underlying condition is found that is surgically treatable such as fluid within the pericardial sac, then that surgery may be performed to see if the chylothorax will resolve.

Occasionally, when the lungs are floating in fluid, they twist on themselves. When this happens, even more fluid is produced and the situation can become very quickly life-threatening. If you notice a sudden worsening of your pet's condition you should see your veterinarian as soon as possible.

When chylothorax has been present for a long time, the lining of the lungs becomes scarred and thickened (fibrosing pleuritis). This may prevent the lungs from expanding normally. Treatment of this condition is difficult. The thickened lining can be removed surgically, but this often results in air leakage from the lungs. When fibrosing pleuritis is present, the prognosis is very guarded.