It’s the time of the year that Arizona residents and winter visitors have been waiting for — temperatures are perfect and the hiking trails and walking paths are filled with people who are outside with their pets, enjoying the Arizona winter. While you enjoy exercise with your pet, you may notice your companion is lagging behind, panting or breathing loudly, or coughing. Change in exercise tolerance, increase in the rate and effort of breathing at rest, and coughing are important indicators of heart and lung disease.
Older, large-breed dogs can develop very noisy breathing or voice change due to partial or complete paralysis of the laryngeal cartilage that allows air to enter the lungs. The cartilages protect the airway when dogs swallow, so paralysis can lead to inhaling water or food, which can cause pneumonia. Laryngeal paralysis can also cause life-threatening overheating because panting is the only way that dogs can cool their body and laryngeal paralysis interferes with this vital cooling mechanism. If you have concerns about a change in voice, noisy breathing, or heavy panting long after exercise, your veterinarian should be consulted.
Yearly physical examination with your veterinarian is the best way to identify the onset, and progression, of a heart murmur or abnormal heart rhythm. Heart murmurs are common as dogs age and not all murmurs require treatment. A heart murmur is a sound caused by blood leaking between the valves that direct blood flow through the heart and lungs. Young dogs can be born with a heart defect and older dogs can have age-related changes to the valves that cause them to leak. Leaking valves can cause heart enlargement, which causes a cough. If the heart fails, fluid can build up in the lungs or in the abdomen. Loss of exercise tolerance, a persistent and progressively worse cough, a bluish color to the tongue, or a suddenly distended belly all warrant a veterinary check-up.
A persistent cough can indicate lung disease without heart disease. Dogs can have seasonal allergies that are worse as the weather cools down. If your dog coughs every winter, but is better in the summer (or vice versa), your veterinarian may be able to help manage the seasonal cough with oral medications. Some dogs have more severe lung disease, similar to asthma in people. The immune cells in a normal, healthy lung can remove inhaled bacteria in a matter of days, but in chronically inflamed lungs, the immune cells are not as effective. If you have a dog that has a chronic cough that suddenly gets worse, he should be seen by your veterinarian to make sure that he doesn’t have pneumonia.
Infectious bronchitis is spread through the air, and can be passed from dog to dog at doggie day care, kennels, dog parks, and grooming facilities. We often think of this type of bronchitis as “kennel cough,” which is a contagious but self-limiting infection in healthy, young animals. Very young dogs, older dogs, or dogs with other chronic illness can develop pneumonia from kennel cough. Bringing a new dog from a rescue or shelter into your home is one way that older dogs are exposed to infectious bronchitis.
In Arizona, cough and exercise intolerance can be a sign of Valley fever infection. Valley fever is a fungal infection (Coccidioides immitis) that is inhaled and becomes a systemic infection. Valley fever can go everywhere in the body and causes fever, lethargy, cough and decreased appetite. The majority of dogs that are born and live in Arizona clear a Valley fever infection without needing veterinary care. However, the dogs that do need care can be extremely sick. Valley fever can settle in the lungs, around the heart, and in the bones. Valley fever can be tricky to diagnose, so repeated blood work and radiographs of the chest may be needed. Winter visiting pets, older pets, and pets with chronic illness are at increased risk of infection. In some cases, winter visiting pets return home to areas where Valley fever does not occur, and it can be difficult for out of state veterinarians to make a diagnosis.
If you are concerned that your pet is not able to keep up on walks, or is coughing more than he used to, it would be best to see your veterinarian so that you and your walking partner can get back out there and enjoy the Arizona winter.
Janet K. Bailey, DVM, Diplomate ACVIM, is an internal medicine specialist at Southern Arizona Veterinary Specialty and Emergency Center.