Yes, they certainly can. Just like in humans, any disease that causes sufficient damage to the lungs and respiratory tract weakens their ability to protect themselves, meaning that opportunistic bacteria can sneak in and set up a serious – even life-threatening – infection.
What sorts of things can cause pneumonia?
We tend to see of pneumonia in three different situations.
Firstly, where there has been a severe infection of the respiratory system – such as some cases of Kennel Cough, or Distemper virus infection (now fortunately rare due to routine vaccination). In this case, the virus or bacterium causing the initial infection so weakens the dog’s immune system that other bacteria (so-called “opportunistic” species, or “secondary invaders”) can establish an infection. These bacteria are often normally present in small numbers in the respiratory tract (especially at the back of the throat), but while the dog’s immune system is off busy dealing with the initial infection, they multiply dramatically and invade the lungs.
The second situation is when the dog’s immune system is weakened by something else – another disease or condition (not an infection), that makes it less efficient at seeking out and killing bacteria. Common examples would include dogs with Cushing’s Disease, Diabetes, or tumours (especially of the respiratory tract). However, dogs on certain immunosuppressive medicines (such as high doses of steroids, or cyclosporine) are also at an increased risk, as are those undergoing chemotherapy.
Finally, the third situation is where the dog accidentally inhales liquid or food – we call this Aspiration Pneumonia. This is very, very unusual in a normal healthy dog (they may cough a bit if some food goes down the wrong way, but that’s because they’re getting rid of it before it can cause a problem!). However, we do see it in puppies with a cleft palate, dogs with chronic vomiting, or after a non-fatal drowning. In addition, if there is a malfunction of the larynx (the “voice box”, a sort of cartilage trapdoor at the top of the windpipe, whose primary function is to prevent anything other than air entering), aspiration is much more likely. As a result, Aspiration Pneumonia is pretty common in dogs with laryngeal paralysis who have had a tie-back surgery, for example.
Can dogs catch it from each other?
Most cases of pneumonia aren’t strictly speaking contagious – however, the primary disease may be! Perhaps the most common underlying cause is Kennel Cough, which is one of the most infectious diseases we see on a regular basis.
So, what actually happens inside the dog?
As the bacteria become established in the lungs, they cause fluid to ooze out into the airways, blocking them and preventing air from getting into the bloodstream. Sometimes, the bacteria may in fact penetrate the tissues of the lung as well – we call this interstitial pneumonia, although it is less common.
What are the symptoms?
A dog with pneumonia is really, really ill – if they look OK in themselves, they probably don’t have pneumonia! These dogs usually are struggling to breathe, and often extend their head and neck, and hold their elbows out from their chests, to get more air in. They often breathe very fast, and usually have a cough. In most situations, they will be running a high fever, be listless and lack appetite. Sometimes, you will hear audible wheezes from their chest, and when the vet listens, they’ll often say they can hear “crackles” – caused by bubbles of fluid within the lung’s airways. In some cases, dogs will also have a profuse runny nose, as fluid from the lungs bubbles up into the throat and out.
How is it treated?
Milder cases can often be treated at home with powerful antibiotics and sometimes medications to open up the airways; however, many dogs are so sick that they need to be hospitalised and treated with intravenous antibiotics, fluids, and sometimes oxygen therapy as well. Fortunately, most simple bacterial pneumonia cases recover well, although aspiration pneumonia is much more serious.
In the recovery phase, we’ll sometimes recommend physiotherapy to help shift the fluid, and it may take them weeks or even months to bounce back fully.
Can it be prevented?
The best way to prevent pneumonia is to keep your dog’s vaccines up to date – better vaccination means that they are less likely to contract the initial infection that leads on to pneumonia.
If you think your dog may have pneumonia, call us for advice right away.