By Dr. Laura Hady
I think we take for granted the three critical functions of our pet’s respiratory system unless there is a problem with breathing or coughing. Air comes through the nose and mouth, is directed to the trachea (windpipe), goes to each lung via tubes called bronchi, enters a series of air tubes called bronchioles in each lung lobe, and finally reaches the millions of alveoli (air sacs). This is where oxygen from the room air is exchanged with carbon dioxide, which is then exhaled back up the “tree” of airways.
Lungs are also important in temperature regulation via panting to release heat because pets have only a few sweat glands. Finally, lungs provide protection through a thick mucous lining that traps and destroys particles and bacteria. For reference, most pets breathe 15–30 times per minute. The following are some issues that can happen in different locations of the respiratory system pathway and can be differentiated from heart disease during a veterinary appointment.
1) Collapsing Trachea
Collapsing trachea is a condition seen in toy breed dogs such as Pomeranians, Chihuahuas, and Poodles. If we think of the trachea (windpipe) as a straw, these breeds can develop a bend or narrowing of the trachea that results in less air reaching the lungs. These dogs tend to cough when excited, while eating or drinking, or when a collar is tightened as a leash is pulled. Pups are usually born with the abnormality, which worsens over time.
Diagnosis is typically made through a physical exam and radiographs of the neck and chest. Medications such as cough suppressants, steroids, and opioids may be used to provide relief. Surgery involves placing an expanding, net-like stent that helps keep the airway open.
2) Laryngeal Paralysis
Laryngeal paralysis usually affects older, large-breed dogs such as Labrador Retrievers, Huskies, and Rottweilers. It is caused by a loss of function of the nerve that controls the opening of the larynx (voice box), which allows air to enter the trachea but closes when a dog eats or drinks.
Owners may notice raspy breathing or excessive panting at first, which may progress to coughing, exercise intolerance, and a tongue color that is no longer pink. Since the larynx is not opening and closing properly, less air is directed to the trachea, and there is a greater risk of aspirating food, which can cause pneumonia.
While medication may help in the early stages, “tie-back” surgery is the preferred method to open the larynx and improve breathing.
3) Asthma
Asthma is more common in cats and is an allergic reaction to inhaled substances. It results from the body’s immune cells producing antibodies to irritating substances such as pollen and smoke, causing inflammation. The inflammation causes swelling, narrowing of the airways, and increased mucus in the passages, resulting in difficulty breathing.
Cats may exhibit open-mouthed breathing, wheezing, an increased respiratory rate, and a hacking cough that sounds more like vomiting. Many cats will hunch their bodies while extending their necks.
Diagnosis includes a physical exam and radiographs, where the lungs will often appear overinflated and extra air may be noted in the stomach. Some specialists use bronchoscopy to examine the airways and collect samples for analysis.
Treatment depends on the cat. Some cats tolerate only oral or injectable steroids, while others can tolerate inhalers that help relieve inflammation and open the airways.
4) Canine Infectious Tracheobronchitis (Kennel Cough)
Canine Infectious Tracheobronchitis, commonly known as kennel cough, is a highly contagious infection caused by a virus with a secondary bacterial infection (Bordetella bronchiseptica). Incubation is typically seen 3–10 days after exposure to an infected dog during boarding, grooming, or visits to dog parks.
Similar to a human cold, dogs may have nasal discharge and a loud honking cough. The infection is usually self-resolving when treated with anti-cough medications, but some dogs require antibiotics.
Dogs can be routinely vaccinated for kennel cough, although some vaccinated dogs may still contract the infection with milder symptoms.
5) Pneumonia
Pneumonia can be caused by viruses, bacteria, fungi, parasites, or aspirating food. Dogs and cats may experience reduced appetite, coughing, and low energy. Fluid buildup can be heard as wheezes or crackles when your veterinarian listens to the lungs.
Bloodwork, radiographs, pulse oximetry to check oxygen levels, and even bronchoscopy may be performed to determine the cause. Oxygen therapy and nebulization with antibiotics or drugs that help open airways, such as albuterol, may be used.
Veterinarians do not normally recommend cough suppressants in pneumonia cases because coughing helps remove infection and fluid from the airways.
6) Pneumothorax
Pneumothorax is simply outside air accumulating in the pleural space surrounding the lungs. It can cause extreme difficulty breathing and even death. Pneumothorax may occur after trauma, such as a pet being hit by a car or a cat jumping from a roof.
Pets may exhibit labored breathing, reluctance to walk or exercise, standing with elbows out to help expand the chest, crackling air under the skin, and bluish gums. A physical exam may reveal reduced lung sounds when a veterinarian listens to the chest.
Radiographs can show the outline of free air, and the heart may appear elevated off the chest wall. Treatment involves removing the air with a needle and chest tube. Surgery is sometimes required to repair an air leak.
For animals with trauma, radiographs may reveal a hole in the diaphragm with organs such as the stomach, intestines, or liver pushed into the chest cavity. Surgery is usually successful in removing the displaced organs and repairing the diaphragm.
Getting your pet to your veterinarian when you first notice increased breathing, difficulty breathing, or coughing is the first step toward treatment. Unless breathing issues are caused by an infection, medical treatment may be lifelong, and surgery may provide the best outcome.
