Pneumonia and Respiratory Infections
Infectious pneumonia is a bacterial, viral, fungal or, less commonly, a parasitic infection of the lungs that causes difficulty breathing. Infectious pneumonia occurs in both cats and dogs. A bacterial and/or viral upper respiratory infection or “cold” can potentially turn into pneumonia if left untreated. Pneumonia can also occur as a result of aspirationaccidental sucking in of food particles or fluids into the lungs of food or other materials into the lungs, which happens when a pet inhales or chokes on food, water, vomit or other materials.
Bacteria and viruses that cause pneumonia are easily spread through close contact by touching noses, grooming and sharing food or water bowls. Even if pets are not in direct contact with each other, pathogensinfectious agent that causes disease or illness to its host that cause pneumonia are easily transmitted through the air when an infected animal coughs or sneezes. Thus, pets that have recently been in contact with other pets at boarding facilities, pet daycare or shelters may be at a higher risk for becoming ill with a respiratory infection and, later, pneumonia. Young or elderly pets may have weaker immune systems so could be more at risk for developing pneumonia from an upper respiratory infection.
Aspiration pneumonia differs from infectious pneumonia in that it is not contagious. Pets who have aspiration pneumonia have choked on their own vomit and therefore aspirated vomit into their lungs. There are many reasons for vomiting, from dietary indiscretiontendency of certain animal of eating unusual items in dogs and hairballs in cats to more serious medical conditions affecting the liver, kidneys and pancreas. A pet with aspiration pneumonia should always undergo testing to determine the initial cause of illness and vomiting. Aspiration pneumonia is not overly common and should not be suspected with every vomiting episode. Aspiration is a risk when a pet is under or recovering from anesthesia, which is why your veterinarian will commonly tell you to withhold food and water from your pet prior to performing surgery. Aspiration is also a risk for pets during seizures.
Signs of Pneumonia
If your pet has pneumonia, you may notice signs like coughing, lethargy, lack of appetite or heavy breathing. While it may seem counterintuitive, many pets with pneumonia do not have a fever when examined by their veterinarian. A hallmark sign of pneumonia is a deep, soft cough that may not be productive, meaning your pet may or may not cough up mucus. The lung sounds of pets with pneumonia may sound loud and harsh or may be soft, as air is not circulating through areas of lung tissue affected by pneumonia. If your veterinarian suspects your pet suffers from pneumonia, they will likely ask for complete X-rays of your pet’s chest and a CBC (complete blood count)broad screening test to determine an individual's general health status. The X-rays provide a picture of your pet’s lungs so pneumonia may be visually confirmed. The CBC looks for abnormal levels of white blood cells (WBC), which is sometimes seen in a pet with pneumonia. White blood cells are the cells that fight infection, and levels can be high or low and even normal, depending on how long your pet has had pneumonia.
If your pet has been diagnosed with pneumonia but is still happy, eating, drinking and acting fairly normally, your veterinarian will likely send your pet home with medications, including antibiotics. Your veterinarian may also instruct you to keep a close eye on appetite and activity level. These more mild cases of pneumonia are similar to “walking pneumonia” diagnosed in humans. With these mild cases in humans, normal daily tasks can be completed, but extra rest, fluids and antibiotics are prescribed usually. Likewise, your pet with mild pneumonia needs extra rest, so no walks or outdoor playtime. If your pet stops eating or becomes lethargic, your veterinarian will likely recommend hospitalization.
Oxygen Support May Be Necessary
Pets with moderate-to-severe pneumonia require hospitalization. These pets are not eating or drinking, are lethargic and may not be breathing normally. Pets with difficulty breathing will need to be placed on oxygen until breathing returns to normal. Oxygen support occurs by placing your pet in an oxygen kennel or fitting them with nasal cannulas, which are non-painful, flexible, short, plastic tubes placed in your pet’s nostrils. Not all veterinary clinics are equipped to provide oxygen support for extended periods of time, so it is possible your veterinarian may have you take your pet to an area emergency clinic or specialty hospital for treatment. In addition to oxygen support, your pet will be placed on Intravenous (IV) fluids and IV antibiotics and given nebulization treatments. Bloodwork will be monitored daily, and X-rays may be repeated to monitor the appearance of lung tissue. If the pneumonia occurred secondary to aspiration, additional treatments targeting the primary cause of vomiting will be needed.
If hospitalized, most pets will stay in the hospital for two to three days, but hospital stays of five to seven days are not uncommon in severely ill pets. Pets that are hospitalized longer than two to three days and are not eating will need nutritional support through a feeding tube.
The Recovery Period
Whether your pet was hospitalized or was able to be treated at home, it will take about two to three weeks for your pet’s lungs to fully recover from a bout of pneumonia. During this recovery period, your veterinarian will have your pet on antibiotics and will instruct you to restrict your pet’s activity level. Even if your pet seems to be recovering outwardly, it is important to follow your veterinarian’s guidelines. Your pet is likely to be short of breath or could experience extreme difficulty breathing if allowed to exercise. At the end of the recovery period, your veterinarian will suggest you return to the clinic for another set of X-rays. If these X-rays show the pneumonia has resolved, your pet will be given permission to return to normal activity. If the pneumonia has not fully resolved by this time, your veterinarian will probably prescribe additional antibiotics and instruct you to continue to keep your pet well-rested.
Pneumonia can be prevented by making sure your pet is up-to-date on vaccines, especially for kennel cough in dogs prior to boarding or daycare activities. If your pet is coughing or sneezing, has nasal discharge (runny nose), is not eating or lethargic, a prompt veterinary exam is recommended to ensure your pet does not have pneumonia.
Dr. Christine New practices veterinary medicine at the Hillside Veterinary Clinic in Dallas.