Pneumothorax in Cats

A pneumothorax condition is defined as free air within the pleural space (chest cavity). The naturally occurring intra-pleural pressure maintains an equilibrium of roughly 5 cmH20, similar to a vacuum which allows easy expansion of the lungs. However, unwanted air can enter this vacuum system and the equilibrium is set to match that of the chest cavity rather than the lungs. Pneumothorax can occur due to trauma, such as the action of a punctured lung will allow atmospheric air to enter the pleural space.

Pneumothorax in cats is characterized by air occupying the space surrounding the lungs. The lungs are the body’s natural oxygen storage organs, expanding as the feline inhales, but if air is surrounding the lungs it restricts normal lung activity. Pneumothorax in cats can be caused by ruptured lung tissues, blunt force trauma and bite wounds. If your cat is suffering from pneumothorax, he or she will have a great breathing difficulty, which is often fatal if left untreated.

Pneumothorax in cats will make inhalation and exhalation extremely difficult for the feline. The most prominent symptom of cats suffering from pneumothorax is difficulty breathing (dyspnea), but other clinical signs a cat owner may notice in the case of pneumothorax in cats includes: 

• Exercise intolerance
• Cyanotic (blue tinged) gums and tongue
• Labored breathing
• Increased respiratory rate 
• Restlessness 
• Sternal recumbency lying (the feline will lay on her sternum in an upright position in an attempt to bring more air into her lungs)
• Anorexia
• Tachypnea (shallow, rapid breath)
• Open-mouthed breathing

Types

Pneumothorax in cats is classified into three separate groups; iatrogenic, spontaneous and traumatic. 

Iatrogenic Pneumothorax 

The result of medical mishap during a surgical procedure. Common surgical procedures that sometimes result in pneumothorax in cats include lung surgery, intubation, thoracostomy tube placement, thoracentesis and bronchoscopy. 

Spontaneous Pneumothorax 

The result of no obvious underlying cause, without trauma. Common causes of spontaneous pneumothorax include:

• Ruptured esophagus, lungs, trachea or bronchus.
• Asthma
• Lung and/or pulmonary abscess or cysts
• Parasites in the lungs
• Pneumonia 
• Lung flukes
• Heartworms
• Cancer
• Pulmonary bleb rupture 
• Bullae emphysema 

Traumatic Pneumothorax

The most common cause of pneumothorax in cats caused by: 

• Lung infection
• Falls 
• Hit-by-car accidents
• Broken, fractured ribs
• Stab wounds, bites, and gunshots 

Air can enter the chest cavity in one of two ways, termed open and closed pneumothorax. Open pneumothorax is caused by a hole in the chest wall allowing outside air to enter the pleural space surrounding the lungs. Open pneumothorax in cats is often caused by a bite wound, gunshot to the chest, or blunt force trauma causing a broken rib to tear a hole through the chest wall. Closed pneumothorax is caused by a respiratory leak in the esophagus or other parts of the respiratory system. A closed pneumothorax in cats is often the result of ruptured lung tissues, tumors, and parasite infestation. 

Your veterinarian will begin his or her diagnosis of pneumothorax by reviewing your feline’s medical history and conducting a thorough physical examination. The doctor will listen to the cat’s lung auscultation using a tool called a stethoscope, which will allow the veterinarian to determine respiratory rate and abnormal breathing sounds. After listening to the feline’s lung sounds and speaking with you about clinical signs noted at home, the vet will likely request the following diagnostic exams: 

• Biochemistry profile: aid in the evaluation of the feline’s kidneys and liver.
• Complete blood cell count (CBC): general blood health. 
• Pulse oximetry and arterial blood gas: a test to determine the feline’s ability to oxygenate. 
• Chest radiographs (x-rays): reveal the presence of air in the chest cavity. 

Pneumothorax in cats is often treated as a medical emergency, therefore, your veterinarian will likely place the feline on supportive oxygen care for stabilization purposes. An oxygen cage, oxygen mask, or an esophageal tube may be placed to administer oxygen therapy. The doctor may proceed to conduct a procedure known as a thoracocentesis, which removes the air from the pleural cavity through the action of needle aspiration. If a large amount of air is occupying the chest cavity, the veterinarian may place a chest tube to allow larger amount of air to escape from the chest. If the condition was caused by trauma or leakage of a respiratory organ, the veterinarian will surgically repair the opening. 

Pneumothorax in cats caused by parasites will require anti-parasitic drug therapy and underlying disease will be treated based on the veterinarian’s findings. 

Your cat will likely be hospitalized for a couple of days to remove the air from the lungs and ensure regular breathing habits are set in place. Once the feline is released from the hospital, exercise restrictions are recommended and follow-up care is to be expected. Some cases of pneumothorax in cats can be prevented by keeping the feline indoors when you are not home and keeping up-to-date on parasite preventatives.