Fluid IN the Lungs, Fluid Around the Lungs, and Chylothorax

Let's discuss congestion or CHF a bit more. Fluid in the body is comprised of fluid-water from food and drinking, things digested that the body breaks down, and blood. HCM, which is the enlarging of the heart valves, can lead to fluid build up in the lungs, known as CHF-congestive heart failure. The heart is unable to handle the fluid in the body, is unable to pump it out or take it all into the valves. The leftover fluid then backs up into the lungs. This is called pulmonary edema. When the drainage system in the body goes awry-various reason due to heart disease:

Increased hydrostatic pressure as a result of congestive heart failure (CHF)
Hypoalbuminemia (low levels of protein in the blood)
Changes in blood vessels-hey become "leaky"
Obstruction of lymphatic drainage/abnormal lymphatic function
Chylothorax (accumulation of chyle, a lymphatic fluid that originates in the intestines and has a high concentration of fat).
Diaphragmatic hernia
Hemothorax (bleeding into the pleural space)
Pulmonary thromboembolism (a blood clot in the lungs)
Bacterial, viral or fungal infection of the lungs
Cancer

-fluid can gather outside the lungs in the area between the lungs and chest, called the pleural sac, leading to pleural effusion. Regardless where is the fluid in or around the lungs, a diuretic is necessary to get rid of congestion. BUT fluid in the pleural sac can be drained if the diuretic is not working effectively. However, the necessity to drain the lungs often damages the lungs over time, creating pockets from the needle where fluid can gather and not be reached by draining, making breathing difficult and CHF still likely. Increasing the diuretic dosage is often necessary to further fight CHF.

It is possible for HCM cats, with advanced heart disease, to have the thoracic system fail and allow the buildup of chylothorax, a fatty white fluid that builds up in the pleural sac, causing CHF. This is an added complication and almost impossible to fight. It must be drained with a needle. Myrna developed this the last year of her life and lived 8 months with it. We had fluid drained every other week, increased the lasix, changed the diuretic to a harder one called Torsemide, and tried a supplement called Rutin which is supposed to help. Either she needed more or it wasn't working but it did not seem to end the chylothorax. A low fat diet is recommended also for this condition but I'm not sure what foods are low in fat; we didn't try that with Myrna. Chylothorax further damages the lungs because it is a caustic substance. You can read more here: https://vcahospitals.com/know-your-pet/chylothorax-in-cats
Chylothorax and the necessity to constantly drain the lungs due to pleural effusion, can lead to death-damage to the lungs and increased CHF; and because it is a sign of the heart system failing. Myrna lived eight months with pleural effusion/chylothorax which surprised her cardiologist and the vet hospital where we took her for her necropsy (animal autopsy.)