The Coughing Pet
This information is not meant to be a substitute for veterinary care. Always follow the instructions provided by your veterinarian.
Cough is a common problem in dogs but occurs less frequently in cats. Cough is caused by irritation of the throat, airways or the lungs. The main airway to the lungs known as the windpipe or trachea branches into smaller airways called bronchi which branch several more times as they travel to the deeper parts of the lung. (Anatomy of the lungs and airways: dog / cat)
There are many causes of cough. A thorough history and physical examination help the veterinarian decide which causes of cough are most likely in your pet and helps him or her decide which diagnostic tests to recommend and which therapies are most likely to be effective. Cough originating from the trachea may be stimulated by lightly squeezing the trachea. Cough due to heart disease may be accompanied by a murmur or abnormal heart rate or rhythm.
Your description of the nature of the cough, when the cough occurs, and if anything brings on coughing can be very helpful in pinpointing the cause of coughing in your pet. Some causes of cough result in difficulty breathing between coughing episodes whereas with other diseases, the pet breathes normally between coughing episodes. Some types of cough occur more commonly at night when the animal (and human family members) are trying to rest. Animals with heart failure, collapsing trachea and lung edema cough more at night than during the day.
Cough caused by tracheal irritation or tracheal collapse often occurs when the pet is excited or is tugging on its collar. Cough caused by heart disease may follow exercise or excitement. Cough due to tracheal collapse may be stimulated by drinking water. Coughing that occurs during or shortly after eating may be due to disease of the larynx or esophagus. The larynx normally closes when food is swallowed to prevent food from entering the trachea. If the larynx is diseased it may not close when food is swallowed resulting in food entering the trachea. Food may pool in an abnormally dilated esophagus. The food then may pass to the mouth and down the airways into the lungs causing pneumonia and cough.
Some coughs sound moist and others are harsh and dry. Moist coughs indicate the accumulation of fluid (water, blood or pus) in the airways or lungs. The environment and habits of the pet can influence which causes of cough are more likely. Dogs that hunt or spend time outdoors may inhale grasses, seeds or other foreign materials through the nose into the airways. In addition to causing coughing, foreign materials can travel down the airways and through the lung causing an infection with a large amount of pus to develop in the space surrounding the lung. This disease is called pyothorax. Animals that have exposure to other animals in a shelter or boarding facility are more likely to have an infectious cause for coughing. The region of the country in which you live or to which you and your pet have traveled, influences the likelihood of some diseases like heartworm disease and fungal infections of the lung (histoplasmosis, coccidiomycosis and blastomycosis). Heartworm disease occurs in both dogs and cats and is most common in parts of the country that have lots of mosquitoes.
The age and breed of the pet also influences what causes of cough are most likely. Young animals are more likely to develop a cough due to infections with bacteria or viruses. Young to middle aged cats may develop wheezing and cough due to asthma. Cats with asthma have sudden episodes of wheezing and coughing but are normal in between episodes. Middle aged to older, small breed dogs are more likely to have heart disease due to leaky valves. Middle aged to older, large breed dogs are more likely to develop paralysis of the larynx.
Tracheal collapse occurs most commonly in middle to aged overweight small breed dogs . Tracheal collapse is rare in cats. The cough is often described as sounding like a goose honking. Treatment for tracheal collapse includes weight reduction and intermittent use of cough suppressants and sedatives. Surgery can be performed in dogs with severe collapse that don't respond to weight reduction and cough suppressants but often surgery is not effective.
Kennel cough or infectious tracheobronchitis is caused by several infectious organisms, including bacteria and viruses. Vaccinations are not 100% protective against the agents of kennel cough. Coughing due to kennel cough usually becomes apparent within a few weeks of exposure of your dog to other dogs in a kennel or show environment. Kennel cough usually resolves itself without any treatment. If the cough is severe enough that the pet has difficulty sleeping or people in the house have difficulty sleeping, cough suppressants can be given to suppress the frequency of cough, allowing the pet and human members of the household to get rest while the disease runs its course. If the cough does not subside in a week to ten days, your pet should be evaluated for other diseases of the lungs or airways.
Cough can be caused by heart disease, which is diagnosed by a chest x-ray, an electrocardiogram which measures the electrical activity of the heart, and often by a heart ultrasound which allows the veterinarian to view the inside of the heart, including the valves and the thickness of the walls of the heart muscle. Heart disease may cause heart enlargement that puts pressure on the airways causing cough or the heart may fail and lead to edema of the lungs. (Anatomy of the dog / cat heart)
Allergies to particles in the air including dust, pollens, and smoke can cause allergic lung disease and coughing.
In older patients, lung cancer has to be considered. The lungs receives a large amount of blood that flows through the rest of the body. Lung cancers in dogs and cats most often originate from other organs and are transferred from those organs through the blood to the lung. Some cancers may be controllable with anticancer medication. Single lung tumors that originate within the lung may be surgically removed in some cases.Tests that may be recommended to identify the cause of a cough include a blood profile to screen multiple organs, a stool exam to look for parasites or their eggs that are coughed up and swallowed, chest x-rays or x-rays of the trachea. The larger airways can be examined using a flexible scope called a bronchoscope in a procedure called bronchcoscopy. Sterile fluid can be flushed into the airways to collect samples for culture or microscopic exam. Large foreign bodies in the airways can be removed by bronchoscopy. Specific tests may be performed if heart worm disease or an infectious cause for the cough are suspected.
Treatment of coughing patients depends upon the disease diagnosed and may include cough suppressants, antibiotics for bacterial infections, and steroids for allergic lung disease. Avoid self medicating your pet as the treatment for one cause of cough may be very wrong for the treatment of another type of cough.
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