What is pyothorax?
Pyothorax refers to the presence of inflammatory fluid or “pus” within the chest cavity.
What causes pyothorax?
Pyothorax is usually caused by a bacterial infection in the chest cavity. Usually, pus is present in both sides of the chest although occasionally only one side will be affected.
The source of the infection is rarely found although possible causes include:
What are the clinical signs of pyothorax?
Rapid shallow breathing that may be painful, depression, lethargy, decreased appetite and other signs of illness are seen in most cats with pyothorax. The severity of these signs is extremely variable and cats may suddenly die without having had any previous signs of illness.
Cats with pyothorax usually have a high temperature that contributes to some of the clinical signs. The rapid, open-mouth breathing or “breathlessness” is caused by the presence of fluid in the chest that prevents the normal expansion of the lungs.
How is pyothorax diagnosed?
Clinical examination by a veterinarian may provide some indication of fluid within the chest particularly on listening to the chest with a stethoscope. In severe cases, it may be necessary to drain the chest immediately. In more mildly affected cases, chest radiographs (x-rays) may help to demonstrate the presence of fluid in the chest and its location. Sedation of the cat may be required to allow drainage of the chest. In most cases the pus can be drained from one side of the chest although it may be necessary to drain both sides in some cats. Sometimes, the fluid is present in “pockets” and multiple drainage procedures must be performed. Samples of the fluid should be sent to a laboratory for evaluation and bacterial culture so that the organism responsible can be found and an appropriate antibiotic given.
In cases of pyothorax where no obvious cause is determined, it is recommended that the cat be tested for Feline Leukemia (FeLV) and Feline Immunodeficiency Virus (FIV).
How is pyothorax treated?
Drainage of the infected fluid plays an important part in the treatment of this condition. Drainage may be needed on multiple occasions during the initial treatment period. In some cases, a chest drain may be inserted surgically, allowing drainage of the chest and administration of antibiotics into the chest cavity. Fluids can also be administered via the tube to “lavage” or flush out the chest. This tube may be left in place for several days to allow these procedures to be performed. Treatment with oral antibiotics is essential and the cat may need to stay on these for several weeks. In very sick cats, supportive treatment with intravenous fluids may also be needed in the initial stages.
What is the long-term outlook for a cat with pyothorax?
This depends on the cause of the disease. In those cases where no underlying disease is found, the outlook is frequently very good provided that the cat survives the critical initial stages. Unfortunately, a proportion of cats will die in the early stages of their disease. In those cats that do survive, complications are rare and the long-term outlook is good.