You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Chylothorax is an unpleasant disease which occurs from time to time in animals

Following digestion the nutrients in food pass across the intestine wall. A duct system of "lymphatic" vessels carries fats that have been absorbed from the intestine through the abdomen and chest, and eventually discharges them into the bloodstream. The fluid  that transports them - called chyle - is milky in appearance due to the presence of fat, and the higher the concentration of fat in it the more opaque and white it appears. 

Chylothorax occurs when the duct ruptures and chyle leaks into the chest cavity. The build up of fluid within the chest leads to breathing difficulties and treatment involves draining the chyle off the chest and hoping the duct heals itself. Sometimes the condition continuously recurs and surgery is needed to tie the duct off . The success rate is reported to be 50-60% in both dogs and cats treated at referral centres.  Reducing fat intake is important during the treatment of this condition to reduce the amount of chyle produced.

The cause of chylothorax is usually unknown, but trauma and heart disorders may be involved, as well as tumours that may erode through the duct. Diagnosis involves XRays and the laboratory examination of chyle removed from the chest cavity.

Updated October 2013