Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Chylothorax: A Mysterious Disease of Cats

Pet Column for the week of April 29, 1996

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Linda March
Information Specialist

Chylothorax is a troublesome condition that can be life-threatening for your cat.

According to Dr. Leslie Appel, a veterinarian formerly at the University of Illinois College of
Veterinary Medicine, "Chylothorax is an accumulation of chylous fluid (lymph and lipids) in
the chest."

Lymph is part of the fluid produced by the immune system and the lipids are long chain fatty
acids or chylomicrons. The lymph normally drains from all of the body tissues and empties
into the blood system, removing excess fluid from tissue. If this fluid builds up in your pet's
chest, breathing can become very difficult for the animal.

There are a few conditions, such as trauma, cancer, or heart disease, that are known to
cause chylothorax under some conditions. There are also some cats that get chylothorax for
unknown reasons. "Build-up of fluid around the lungs makes it difficult for the cat to
breathe. Signs may include open mouth breathing or increased respiratory rate," notes Dr.

Some cats may also become lethargic. Or their mucous membranes turn a bluish color
because the blood isn't being oxygenated properly. Owners may also notice coughing and
loss of appetite. If your cat is showing signs of respiratory distress (turning blue, rapid
respiratory rate, open mouth breathing), contact the cat's veterinarian immediately.

By listening to the cat's lungs, and possibly percussing (tapping on the chest while listening
to the chest with a stethoscope), your veterinarian can determine if the cat's chest contains
fluid. Radiographs can also help your veterinarian diagnose chylothorax. If fluid is found,
your veterinarian will want to obtain a sample. If chylothorax is the problem, the fluid will be
milky white or pinkish and opaque. It will also contain large amounts of fat.

Dr. Appel notes, "There are medical and surgical methods used to manage a chylothorax."

Medical management would include monitoring fluid in the chest and removing it as
necessary. Changing to a low fat diet may also help. The cat is then given supplemental fat
in the form of short chain fatty acids that are used immediately by the body. Since this form
of fat is not stored in the blood, it may help decrease the amount of fluid that can build up in
the cat's chest.

If medical management doesn't work, another option is surgical correction. The chest is
opened up and the vessels that carry the lymph are ligated (sewed shut).

"Even with surgery, the prognosis is guarded," states Dr. Appel.
Surgical correction will help about 30 percent of the cats that are effected by chylothorax.
Often, there are many smaller lymphatic vessels that can't be ligated, causing the chest to
continue filling with fluid.

If you have any questions about chylothorax, call your veterinarian.