CHYLOTHORAX

WHAT IS CHYLOTHORAX OR CHYLOUS EFFUSION?

Chylothorax is the accumulation of fatty fluid (chyle) into the chest cavity of animals, that prevents the lungs to expand normally and oxygenate properly.

WHERE IS THE CHYLE (MILKY FLUID) ORIGINATING?

The milky fluid (chyle) originates from the digestions of fatty meals in the intestine, then via the lymphatic vessels, this fluid is emptied into the heart. The main lymphatic duct that carries this fluid across the chest cavity is named thoracic duct and any pathology associated with this duct can cause leakage of chyle into the chest cavity.

WHY IS THE CHYLE NOT ABSORBED BY THE CHEST CAVITY?

The chylous fluid is made of fat, proteins, and white blood cell and due to its viscosity, it cannot be absorbed by the lining of the chest. Additionally, this fluid can cause severe irritation to the lungs and cavity (pleuritis).

WHAT IS THE CAUSE OF CHYLOTHORAX?

Most commonly, the cause of chylothorax is unknown (idiopathic), and probably caused by a backup of chyle in to the duct. Therefore, the high-pressure fluid leads to leakage of chyle into the thorax. Other potential causes of chylothorax include cancer, heart disease and blood clots that obstruct the drainage of the chylous fluid into the heart.

HOW DO I KNOW THAT MY DOG HAS CHYLOTHORAX?

The classic sign of chylothorax is difficulty breathing (panting, lethargy, labored breathing, and blue discoloration of the tongue etc.) due to the accumulation of fluid into the chest cavity.

WHAT ARE THE TESTS TO DIAGNOSE CHYLOTHORAX?

If your dog presents with labored breathing, he or she should be seen immediately by a veterinarian. The tests that should be performed to detect accumulation of fluid into the chest cavity include to listen to the lung and heart sounds (auscultation), chest x rays, ultrasound of the heart (echocardiogram), and analysis of the fluid (culture, triglyceride and cholesterol levels).

WHAT IS THE TREATMENT FOR CHYLOTHORAX?

There are different options to manage chylothorax patients, the first is the medical management, which includes placing a chest tube to drain the fluid, and adding a special diet (low fat) and supplements (rutin). The other option is surgery, which includes ligating the main lymphatic duct (thoracic duct), breaking down the sac collecting the chyle (cysterna chyle), and lastly removing the sac around the heart (subtotal pericardectomy).

WHAT ARE THE EXPECTIONS WITH CHYLOTHORAX?

There is not guarantee with medical or surgical management of chylothorax. It has been documented that patients diagnosed with chylothorax and managed with the combination of surgery, diet and supplement can have a resolution of clinical signs.