흉수에서 유미흉의 X-ray 비교

[scwon]

pleural effusion in a cat

When the fluid is blood, the problem is called “hemothorax.” When the fluid is pus, the problem is called “pyothorax.” When the fluid is actually air, the problem is “pneumothorax.” When the fluid is lymph, the problem is called “chylothorax.” The fluid is milky when it is drained from the chest, its whiteness being from fat.

Causes - A variety of diseases may lead to the development of pleural effusion. Analysis of the fluid and other diagnostic tests help determine the underlying cause of the effusion.

• Transudative fluid may accumulate in the pleural space in association with decreased oncotic pressure or increased hydrostatic pressure within the blood vascular system. Animals with marked hypoalbuminemia (< 1.5 g/dl) have low oncotic pressures that may result in the leakage of fluid into the pleural space. Increased hydrostatic pressure is most often associated with cardiomyopathy and congestive heart failure in the cat. Overzealous fluid therapy theoretically increases hydrostatic pressure, but pulmonary edema is a more common complication of overhydration than is pleural effusion in the cat. With chronicity, transudates may become modified transudates because of secondary inflammation associated with the fluid accumulation.
• Inflammation or infection of the pleura and adjacent tissues may result in the accumulation of exudative pleural fluid. These fluids may be septic, such as those associated with penetrating wounds and secondary pyothorax, or nonseptic such as those associated with feline infectious peritonitis (FIP). Other potential causes include pneumonia, esophageal diseases, and diaphragmatic hernias.
• Neoplastic effusions may develop with mediastinal lymphoma, thymoma or squamous cell carcinoma, with pulmonary neoplasms, and rarely with mesothelioma.
• Obstruction or rupture of the lymphatic thoracic duct leads to the accumulation of chyle in the pleural space (chylothorax). Chylous effusions may also occur secondary to heart disease, certain infections, and neoplasia.
• Hemorrhagic effusions may occur following trauma and surgery, or in association with clotting abnormalities (particularly warfarin toxicity).
• Eosinophilic effusions have occasionally been recognized in association with pulmonary parasites, pneumothorax, and neoplasia.
• Combined pleural and abdominal effusions also develop in the cat, and are most commonly associated with feline infectious peritonitis; heart, liver and kidney disease; and neoplasia. These effusions are frequently modified transudates

Radiographs of pleural flui

	Feline chest radiograph from a patient with chylothorax. The "white out" is fluid (chyle) filling up the chest cavity.

When the fluid is lymph, the problem is called “chylothorax.” The fluid is milky when it is drained from the chest, its whiteness being from fat. In chlyothorax, thoracic fluid triglyceride levels should be much greater than blood triglyceride levels.

 if there is heart disease or thoracic neoplasia that could lead to chylothorax.

when examined under the microscope, it is found to have large numbers of lymphocytes (a type of white blood cell found in lymphatic fluid). Additionally, the fluid may be cultured for bacteria but it is almost always sterile.

Once the presence of chylothorax is confirmed, additional tests will be performed in an attempt to identify an underlying cause. Such tests include blood work, additional chest and abdominal radiographs, tests for leukemia virus and immunodeficiency virus, cardiac tests, and heartworm testing.

In the dog, the definitive cause of the pyothorax is found in only 4 - 14% of cases
while in cats the cause is found in 40 - 67% of cases.

A normal chest cavity	This cat has an effusion in its pleural cavity. In this case the fluid is chyle, not pus, but pyothorax might look the same.