Chylothorax in pet cats has always been a difficult case to solve in the past. In recent years, with the scientific feeding, various nutritional supplements in place, and the implementation of immune and deworming procedures, the number of non-traumatic chylothorax cases has decreased. , but we should still pay enough attention to it. As the fatty liver in cats continues to increase, chylothorax will also become a potential hidden danger. ​​​​​​

Chylothorax refers to the accumulation of chyle in the chest cavity. Chyle comes from the thoracic duct, which contains lipid-rich lymph fluid from the body. Chyle usually looks white and turbid to the eye, mainly because of the chylomicrons in it. Occasionally, the chyle fluid may also be light red, or it may be a clear and colorless liquid, especially in anorexic animals.

Chylothorax can be classified as congenital, traumatic, non-traumatic and idiopathic. Traumatic causes are divided into surgical (thoracotomy) and non-surgical (car accident). Non-traumatic causes include tumors (mainly mediastinal lymphoma in cats), cardiomyopathy, pericardiopathy, heartworms, right heart failure, lobar torsion, diaphragmatic hernia, and systemic lymphangiectasia. Idiopathic chylothorax is diagnosed when no underlying disease is detected.

Chylous exudate may come from intact lymphatic vessels or from chyle leaking from a perforation of the thoracic duct. Obstruction of lymphatic flow often results in intralymphatic high pressure, lymphatic dilation, and subsequent lymphatic extravasation. In cats and dogs, chylothorax can be primary, but a number of factors can cause the disease, including cardiomyopathy, thoracic and mediastinal tumors, mediastinal fungal granulomas, heartworms, congenital lymphatic defects, trauma, chronic Vomiting or coughing, lymphangiectasia or rupture of lymphatic vessels, diaphragmatic hernia, lobar torsion, and venous thrombosis. Rupture of the thoracic duct can occur secondary to trauma and was previously thought to be the sole cause of chylothorax, but in most cases the thoracic duct remains intact.

Determine treatment plans based on different causes. Both medical and surgical treatments are available. If possible, the underlying cause and primary disease should first be identified and corrected. Medical treatment includes thoracentesis, dietary therapy, and drug therapy. Dyspnea can be relieved by thoracentesis and drainage. Initially, a needle can be used for thoracentesis, but if daily drainage is required, a drainage tube will be required. Traditionally, it is believed that placing animals on a low-fat diet reduces the absorption of lipids through the intestinal lymphatic vessels. But in fact, reduced amounts of fat-soluble vitamins, lipids, and protein-rich lymph fluid can lead to malnutrition in animals. New research shows that a low-fat diet does not reduce leakage. It was once thought that supplementation with certain medium-chain triglycerides could provide additional lipids and shunt the thoracic duct because they could be absorbed directly through the portal circulation. However, recent data suggest that medium-chain triglycerides do not divert thoracic duct diversion. In some cases of malnutrition, parenteral nutrition may bypass the gastrointestinal system and reduce lymphatic flow.

For cases that cannot be solved by medical means, surgical methods can be used. Applicable methods include thoracic duct ligation, pleuroperitoneal shunt and intrapleural biological drainage of omentum. Thoracic duct ligation has a curative effect of 20% to 60% on primary chylothorax in dogs and cats. Mesenteric lymphangiography is useful to determine the anatomic location of lymphatic vessels before performing ligation. Whether it is chylous or non-chyloexudate, it may accumulate after thoracic duct ligation.

Postoperative infusion support and combined use of antibiotics are required. The drugs that can be used include metronidazole, intravenous injection, amoxicillin, subcutaneous injection, and pain management using Tonlidine.