jack Russell terrier dog at vet with stethoscope and x-rays radiograph veterinary care

Pneumonia In Dogs: Causes, Symptoms, Treatments And More

It's always scary when your pup isn't right. Our older dog Brody got sick with a cough over the summer and it was pretty scary. We all, including the vet, were hoping it was just pneumonia (which is still serious), since the worst case scenario was lung cancer. Fortunately, after a few weeks of antibiotics, we got the better news that it was pneumonia. It took another two weeks of antibiotics, but our boy finally recovered after being sick for six weeks. We learned a lot about dog pneumonia during this time. So here's an overview of pneumonia in dogs including causes, symptoms, treatments and more.

What is Dog Pneumonia?

Pneumonia in dogs is similar to that in humans - a disease that affects the lungs. It is irritation and inflammation of and within the lungs, including the microscopic air sacs, resulting in swelling and fluid buildup. Often times, there is less room for air within the lungs and a disruption of the normal exchange of oxygen and carbon dioxide, making it difficult to breathe. Though some cases remain mild, it's important to treat pneumonia in dogs with medical urgency and seek vet care as soon as possible, since it can quickly become life-threatening.

Types And Causes Of Pneumonia In Dogs

There are several types and causes of dog pneumonia. Dogs can even have different types of pneumonia simultaneously (most often with secondary bacterial infections). Here are the various types and causes:

Bacterial Pneumonia

Bacterial pneumonia is one of the most common types and is typically quite contagious. It occurs when bacteria enters the lungs, usually through inhalation or aspiration. Most healthy adult dogs do not get bacterial pneumonia as their primary infection but rather as a secondary infection from a larger respiratory illness (such as Bordatella, Bronchitis, Streptococcus, E. coli and more). Puppies and seniors, as well as immunocompromised dogs, can get pneumonia as their primary infection. Other dogs that may be more at risk include those on immunosuppressants or with cancer, airway obstruction, anatomic abnormalities, inhalation of foreign bodies, seizures, vomiting issues, prolonged surgery, viral or fungal pneumonia and more.

Viral Pneumonia

Viral pneumonia, which is spread mainly through inhalation, is caused by one or several viruses and can involve bacteria as well. This type of pneumonia is typically in the lower respiratory tract and quite contagious between dogs. A few common viruses that can cause viral pneumonia include canine influenza, canine distemper, canine adenovirus-2, canine parainfluenza virus and canine herpesvirus.

    Aspiration Pneumonia

    Aspiration pneumonia is not uncommon and occurs when dogs breathe in foreign materials (such as food, water or other liquids, saliva, vomit, medicine, etc.) that then enter the lung airways. For example, inhaled food can partially block airways and trigger inflammation within the lungs. Dogs with a higher risk of developing aspiration pneumonia include those with acid reflux (as stomach acid can damage lung cells), persistent vomiting or regurgitation, laryngeal issues, neurologic disorders, cleft palates and those under sedation or anesthesia or requiring force-feeding. In addition, brachycephalic breeds can be more prone such as English Bulldogs, Pugs, Boston Terriers, French Bulldogs, etc.

    Fungal Pneumonia

    Fungal pneumonia occurs when dogs inhale fungus spores that then enter the lungs. It is seen more in the southern and southwest United States but can affect any dog, especially those living near construction or contaminated dirt or plants. Some common funguses that can cause pneumonia include Aspergillus, Candida, Blatomyces, Histoplasma, Cryptococcus and Coccidioides immitis. Though these will vary depending on where you and your dog live.

    Parasitic and Protozoal Pneumonia

    Parasitic and protozoal pneumonia are more rare but occur when living parasites enter and reproduce in a dog's lungs. This type of pneumonia can be contracted through mosquitos (such as those carrying heartworm) as well as feces contaminated with parasites like neospora and toxoplasma. These tend to affect puppies and dogs with low immunity (e.g. those with cancer, diabetes, severe kidney disease, on immunosuppressant medications, etc.) more than others. In addition, Cavalier King Charles Spaniels and Dachshunds can be particularly susceptible to a rare type of protozoal pneumonia because of a breed-specific inherited immune system defect.

    Inhalation Pneumonia

    Inhalation pneumonia, which differs from aspiration pneumonia, can occur if a dog breathes in smoke or toxic chemicals, gases or fumes. These toxic substances interfere with the ability of a dog's body to process oxygen, as well as the ability to clear mucus from the lungs. Dogs who live with owners that smoke are at a higher risk of developing lung issues that may lead to inhalation pneumonia.

      Eosinophilic or Allergic Pneumonia

      Eosinophilic or allergic pneumonia occurs when a dog’s immune system causes eosinophils (a type of white blood cell) to enter the lungs leading to inflammation. It is often triggered by irritants and allergy triggers like pollen, spores, insects, parasites, and ticks and tick-born diseases like Rocky Mountain spotted fever and ehrlichiosis.

      Interstitial Pneumonia

      Interstitial pneumonia can occur when there is damage to the lung cells or capillaries (tiny blood vessels). Some causes of such damage include inhalation of toxins or smoke, viral infections and more. There is also a form of interstitial pneumonia known as interstitial pulmonary fibrosis that can affect older West Highland White Terriers.

      Other Causes

      Dogs who have experienced trauma to the chest (such as being hit by a car) can develop pneumonia. Dogs who have been on a ventilator are more at risk of developing pneumonia as well.

      Note: Certain types of pneumonia are contagious to other animals, though not humans. Those caused by infection (like a bacteria or virus) can be transmitted, while those caused by aspiration or trauma typically cannot. That being said, it's always a good idea to play it safe and isolate your dog from other animals if they're diagnosed with pneumonia. Canine infectious pneumonia is often seen in crowded places such as shelters, daycare and boarding facilities, dog parks and sometimes even vet clinics.

      Pro Tip: If your dog is diagnosed with pneumonia, wash their items (food and water bowls, collar and leash, dog bed and blankets, toys, etc.) to minimize the chance for infection to spread. Also, try to consistently wash your hands after handling your dog and avoid kissing them.

      Symptoms Of Pneumonia In Dogs

      Pneumonia causes many symptoms that range from mild to severe and can vary based on the type of pneumonia your dog has. The most common symptoms include:

      • Coughing (which often sounds wet, may be productive and worsen with exertion as well as inactivity)
      • Difficulty breathing, wheezing, shallow or irregular breathing and/or increased panting (can resemble hyperventilation)
      • Runny nose or nasal discharge (which can be discolored, often yellow or green, or bloody)
      • Nasal whistling
      • Fever (body temperature over 101 to 102.5 degrees Fahrenheit)
      • Lethargy and fatigue
      • Difficulty exercising or inability to do so at all
      • Loss of appetite or weight loss
      • Dehydration
      • Vomiting and regurgitation
      • Respiratory distress
      • Discolored mucous membranes (like gums, skin, nasal passages, inside the eyelids, etc.) caused by lack of oxygen in the system with severe cases involving blue-ish gums or skin

      Diagnosing Pneumonia In Dogs

      Diagnosing pneumonia requires a vet, who will use several methods to make the diagnosis.

      1. Physical Exam

      They will start with a physical exam and listen to your dog's lungs with a stethoscope to see if they can hear fluid. Fluid in the lungs can sound like wheezes, crackles and pops or it can make the lungs sound quieter than normal. They may check your dog's temperature for a fever and take a closer look at any nasal discharge or coughing (our vet wanted to hear the cough since different issues create different types of coughs). Also, try to explain your dog's state and symptoms in as much detail as possible. Include any medications and supplements as well as recent socialization, overnight stays, tripsvacations or other travel. Your vet will use all of this information to determine disease activity and if further testing is needed. 

      2. Imaging

      Next, vets often order radiographs, or X-rays, of the chest (and sometimes even a specialized 3-view X-ray to determine severity). It's relatively easy to see fluid and inflammation as it appears gray or hazy rather than empty or black. Some vets may use MRIs or CT scans instead or in addition to x-rays.

      3. Blood Tests And Fluid Samples

      Some vets may order blood tests, like a complete blood count (CBC), to see if there is inflammation and infection in the system. This may also be helpful if pneumonia is caused by vomiting, as it may reveal certain factors that make a dog prone to regurgitation.

      Fluid samples may also be taken to determine the specific pathogen causing the pneumonia, which can help your vet prescribe the best treatment. For example, different antibiotics work better for different bacteria. Samples can be taken from nasal discharge or the respiratory tract, which requires special procedures and instruments. A few procedures include:

      • Bronchoalveolar lavage - when a scope is passed through the mouth or nose into a lung airway where a saline solution washes the airway and a fluid sample is taken.
      • Transtracheal or endotracheal wash - when a tube or catheter is inserted into the trachea to evaluate the lungs and capture a fluid sample.
      • Bronchoscopy - when a scope is inserted (usually through the nose or mouth, but sometimes through tracheotomy) to examine the lungs and airways.

      4. Blood Oxygen Analysis

      Some vets want to make sure your dog is getting enough oxygen or to confirm respiratory dysfunction, so they may use pulse oximetry and blood-gas analysis. Pulse oximetry involves used an infrared light to read oxygen levels in the capillaries, while blood-gas analysis requires a catheter to collect blood. These tests are often used as part of follow-up visits to help analyze the effectiveness of treatment.

        Treating Dog Pneumonia

        Treatment of dog pneumonia depends on the type, severity and your dog's overall health. Mild cases typically require medicine, rest and home care. More moderate and severe cases may require vet monitoring or hospitalization (often at emergency facilities). Some common treatments include:

        • Antibiotics or other antimicrobial medicine - the type of medicine depends on the cause of pneumonia. For example, antibiotics are given for bacterial pneumonia, anti-fungals for fungal pneumonia and parasite treatment for parasitic pneumonia. Typically, a two week dose and follow-up are prescribed, though sometimes dogs are on medicine for over a month (like our dog was). The most often used antibiotics are Doxycycline (this is what Brody took), Fluoroquinolone and Amoxicillin.
        • Other medications - such as anti-inflammatories, expectorants to encourage coughing, cough suppressants (typically only to help your dog sleep through the night), bronchodilators to open the lung's airways, immune system support, anti-vomiting medication for those with aspiration pneumonia, steroids (less common) and appetite enhancers (some dogs with pneumonia don't want to eat, but good nutrition is important recovery).
          • Pro Tip: A few ways to make food more enticing is adding toppers, pumpkin and warming up food. In more moderate cases, medication can be used and in severe cases, feeding tubes may be required.
          • Rest and short exercise - restricting activity ensures your dog rests and sleeps enough to recover. That being said, short stints of exercise can help break up mucus and encourage dogs to expel or cough it up.
          • Humidifiers or nebulizers and coupage - humidifiers and nebulizers increase humidity to promote hydration of airways using a saline solution (antibiotics can be added too). Coupage is firm but gentle tapping on the area outside the lungs (side of the body closer to shoulders than hind legs) with slightly cupped hands. These methods can help break up mucus and clear out fluid.
          • Supplemental oxygen and oxygen therapy - this is provided to dogs who are not getting sufficient oxygen into their system. Sometimes vets use a face or nose mask, though more often they use an oxygen cage (an enclosed chamber where oxygen can be increased in a less stressful way).
          • IV fluid therapy - this is given to dogs who are dehydrated, as dehydration can negatively impact the body's respiratory function and clearance.
          • Ventilation - this is used in severe cases if supplemental oxygen therapy is ineffective and requires full sedation.
          • Surgery - if pneumonia is caused by foreign bodies or abscesses, surgery may be required to remove these.

          Most vets will want to continue treatment for a week or two even after your dog's symptoms have resolved as infection can linger without clinical signs.

          Pro Tip: Keep dogs warm and dry indoors and avoid exposing them to cold temperatures or wet weather.

          Prognosis, Recovery And Management Of Dog Pneumonia

          The prognosis for dogs with pneumonia is typically good, as long as they receive proper treatment. Most dogs fully recover, though they may now be prone to future relapses). For instance, studies showing that between 77% and 94% of dogs with bacterial pneumonia survive. Recovery time will vary based on the severity of the disease, the underlying cause and your dog's overall health and age. It usually takes a few weeks to months for dogs to completely recover. During that time, your vet will likely want to do follow-up visits and treatment monitoring (such as redoing x-rays or bloodwork) for weeks or months to watch progress.

          Preventing Pneumonia in Dogs

          It's not always possible to prevent your dog from catching pneumonia. For example, both of our dogs caught a respiratory infection that we didn't know was going around, but only our older dog came down with pneumonia (likely due to his age and kidney disease). That being said, there are a few ways to minimize the risk:

          • Take your dog to the vet regularly for physical exams, as well as fecal tests.
          • Ensure they stay up-to-date on their vaccines (like Bordatella) and consider getting your dog vaccinations specifically for pneumonia. 
          • Keep your dog on parasite medication year-round (such as heartworm, flea and tick preventatives).
          • Don't let your dog stay wet or out in the cold for too long.
          • Take your dog to the vet as soon as possible if they develop a cough or are acting lethargic, unwell or off.
          • Consider limiting how often your dog goes to dog daycare and boarding, as well as dog parks. In addition, if you know there are respiratory infections going around, avoid those areas as dogs can pick up infections just on your daily walks.
          • Make sure your home has good air quality and there isn't any mold or excessive dust. Air purifiers can be helpful for this.
          • Follow vet recommendations for dogs with underlying conditions that may make them more prone to pneumonia.

          As aforementioned, pneumonia in dogs can be life-threatening. Follow these preventative steps to increase your dog's chances of avoiding infection and know the signs so you can act quickly in case. 

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