Pneumonia in Dogs - Causes and Treatments

Pseudomonas

Q: Your mailing prompted me to write back with a question/concern that has been on my mind for some time. I have a 9mo. old viszla who has been coughing and having a hard time breathing since January. The original diagnosis was kennel cough. Through my persistence Oliver had a trach wash and an endoscope to determine what was going on. About 1.5 mos. ago they determined he has pseudomonas in his lungs. I believe that he has had this since January and has gone untreated since that time.

Oliver was on Gentocin (injected daily) for one week, it did not seem to clear it up. He is now on Geocillin. He is still honking (very rarely but nevertheless occassionally) when exerting little energy (jumping off a chair, running to me from a down position). He is also on theophilline.

I am scared. I have been told that pseudomonas is difficult to get rid of in dogs. Moreover, he now has scar tissue in his lungs.

Have you ever dealt with pseudomonas in a dog, and if so, what was your experience? How will we ever know it is gone unless we do another endoscope? What is the worst thing that can happen to Oliver? How might this stuff get into his blood? Also, what does it mean to have scar tissue in his lungs, does it mean he has reduced capacity in his lungs? Answer how ever you feel, I just want a general sense of what we should do. Is he too young to try Batryl? When he was first diagnosed with this I did not want him on the Batryl, was that a mistake in light of the fact it is still not gone? Thanks for whatever you can tell me.

Suzanne.

A: Suzanne-

Pseudomonas species bacteria are one of the more common bacterial causes of pneumonia in dogs. It also is found commonly in chronic ear infections and can invade other tissues in the body. It is one of the bacteria that has developed resistance to many common antibiotics. For this reason, it is best to base the choice of antibiotic used in a Pseudomonas infection on a culture and sensitivity test if at all possible.

Culturing the bacteria is simply getting it to grow on a culture plate from a swab of the lungs or from a tissue sample taken with an endoscope or even surgically. Sensitivity testing involves exposing the cultured bacteria to a number of antibiotics to see which ones kill it on the culture plate at concentrations likely to be present in the blood stream. An antibiotic chosen by culture and sensitivity has a good chance of working well if it also penetrates the tissue that is infected in a reliable manner.

Sulfa and trimethoprim combination antibiotics (Tribrissen Rx, Ditrim Rx, Bactrim Rx) penetrate the tissue well and are relatively inexpensive but bacterial resistance to them is pretty common and there can be problems with these antibiotics if they are used long term.

Chloramphenicol penetrates tissue well and resistance is a little less likely to this antibiotic but many vets are reluctant to dispense chloramphenicol because it has been removed from the human market due to unpredictable fatal aplastic anemia occurring in some humans exposed to the drug. It also has to be given four times a day which is often a difficult schedule for a pet owner to follow.

Gentamicin (Gentocin Rx) is only available as an injection and it has a higher rate of severe side effects than many antibiotics but is sometimes a very good choice in the face of a severe bacterial pneumonia when the bacteria involved is sensitive to it.

Cephalosporins and broad spectrum penicillins (like Geocillin Rx) are often useful in bacterial pneumonias but Pseudomonas species bacteria are usually resistant to these antibiotics. If the culture and sensitivity results support their use I think that many vets would prefer them to other antibiotics due to cost factors and general safety.

Enrofloxacin (Baytril Rx) and the newer fluoroquinolones (Orbax Rx and Dicural Rx) are well distributed in the lungs and usually Pseudomonas is not resistant to them. They can be used chronically, when necessary, usually without harmful side effects. The exception to the quinolones general good safety record is a problem with causing cartilage damage in growing dogs -- so it may have been a good choice not to use them when your dog was younger. This problem seems to be most common in small and medium breed dogs between 2 and 8 months of age and it has only been noted to occur when the Baytril is overdosed but it is still worrisome. Big dogs have a longer growth period but I really think it is safe to give Baytril and the other quinolones at the recommended dosages in a 9 month old dog. I definitely think I would do this if the culture and sensitivity results support the use of a quinolone and Oliver continues to have problems despite the use of Geocillin.

Scar tissue in the lungs is a problem because it can protect the bacteria from the effects of the antibiotic and serve as a way for the lungs to be reinfected even after the pneumonia seems to be under control. In addition, in some cases, the scar tissue can lead to the formation of bullae in the lungs. The lungs are partially composed of lots of tiny air sacs, alveoli, that are the places exchange of oxygen and carbon dioxide occur. When scar tissue blocks the expiration of air from these sacs but allows the inspiration of air they will sometimes rupture forming a larger air sac known as a bullae. This can also lead to chronic respiratory difficulty. It is a good idea to consider follow-up X-rays to look for bullae, collapsed lung lobes and other problems when there are chronic respiratory difficulties after pneumonia or other lower airway infections. X-rays are usually the best way to look for these sorts of problems.

I do think that you should continue to be concerned. It would be a good idea to schedule a recheck with your vet and to discuss your concerns. If you have been using the Geocillin for less than a week it is probably reasonable to give it a chance to work, though.

Mike Richards, DVM

Pneumonia.

Q: Dear Dr. Mike, I have an 8-year old female dog, whose name is April, currently diagnosed to have pneumonia. I just thought it would be wise to request for a second opinion for a number of things concerning her current condition. First, I'll tell you the facts. She probably contracted the illness in an area in the backyard, since she stays outdoors most of the time. That area has caused a lot of our previous dogs to fall ill when they stay there for a period of time. Her temperature is 40oC and she has difficulty in breathing. She has a very weak appetite and was confined to our family vet's clinic for a day with dextrose injected into her system. Since then, I took her home to treat her myself, following the doctors orders of 3 ml 3x/day of Ampicillin (for 7 days), 3 ml 3x/day of Sangobion (bec. she is anemic) and 3ml 2x a day of Mozegor as a supplement. The doctor requested to have her eat only lean ground beef mixed w/ 2 cups of rice and 1 tbsp. of veg. oil each meal. She was supposed to have dicalcium phosphate added into her meal, but I couldn't find any in the drugstore. These are the problems.

All her medicines are in syrup, so I mix them all together and use a large syringe (w/o needle) to give it to her. Unfortunately, that usually amounts to 9ml of bad-tasting medicine, so it is a little difficult to give it to her. Next, she doesn't like her new diet. When I give her other food, such as meat bones, she eats right away. Third problem is, she has a mate who cannot manage being separated from her. Since she's running a fever, I would feel better if April were indoors, but her mate howls all night for her. My questions are: 1) How can I best administer her current medicine? 2) What alternative diet can you suggest so she'll finish her food? 3) Is it extremely necessary to keep her indoors until she recovers? 4) At what point do you think I should start force-feeding her? If she eats half her meal, is that good enough? 5) What can I use to disinfect the backyard and ensure that it is free of any disease-causing bacteria? Dr. Mike, you've helped me once with my other dog, and I truly am grateful for what you have advised on his condition. I look forward to hearing from you soon. Thank you for your dedicated assistance. Regards

A: I hope that April is doing better by now, but just in case:

1) How can I best administer her current medicine?

Liquids can be hard to administer to dogs but usually it can be done by tilting their head back, holding their mouth shut by putting a hand around their muzzle and then working the tip of the syringe into the fold of the lip (back corner of the mouth) and giving the medication just slowly enough that it doesn't run out all over as the dog swallows. Really bad tasting medications can lead to a big struggle, though. It is possible that some of the medications might be OK in taste and your April only reacts due to the bad tasting ones. In this case, separating them may help since she may readily take the OK tasting ones and then you have a smaller volume of the others to give.

2) What alternative diet can you suggest so she'll finish her food?

Personally, I usually tell clients with sick pets to feed them what they want unless there is a specific reason I think it is necessary not to do that, like if they have pancreatitis. Most of the time I think it is better that they eat something than that they eat what I would like them to eat. You need to check with your vet on this one though -- there very well could be a reason for the special diet.

3) Is it extremely necessary to keep her indoors until she recovers?

Probably not --- except that it is important to make sure that she is home when it is time to give medications, so some sort of confinement is a good idea.

4) At what point do you think I should start force-feeding her? If she eats half her meal, is that good enough?

Usually, eating half the meal for a few days is definitely OK. In most illnesses I think it is best to try things like hand feeding good tasting morsels or coaxing the dog to eat in some other way rather than force feeding. In some situations, it is very important to feed and again, you need to check with your vet on that.

5) What can I use to disinfect the backyard and ensure that it is free of any disease-causing bacteria?

Many bacteria are susceptible to sodium hypochlorite bleach (Chlorox is an example). Just general cleaning so that there is no residual stool or other organic material for bacteria to grow in helps a great deal.

Mike Richards, DVM

Pneumonia

Q: Dr. Mike,

I have a 14 year old male Australian Shepherd that was diagnosed last week with pneumonia. The veterinarian has given extensive IV therapy and did not give me a good prognosis. His white blood cell count was 45 and came down to 36 (I was told that 12 is normal). He is home now and I am dosing him with oral therapy. His eating is still not good and he is exercise intolerant. Whenever I take outside, he comes in worn out and panting. What does this mean? Is there a therapy of choice for pneumonia in canines? When should I give up the fight?

Helpless in Kentucky

A: Kirk-

I would not give up on a pet with pneumonia unless there were compelling reasons. I do think that it may be a good idea to get a second opinion (even if you get it from the same vet) because pneumonia is usually responsive to therapy -- though not always. It is important to rule out other possible causes of dyspnea and weakness such as heart failure, lung cancer, anemia, etc. It is not unusual for dogs to have more than one problem when they are elderly and ill. It is also sometimes easier to find a problem such as heart failure or lung cancer after a disease such as pneumonia clears up some.

Good luck with this.

Mike Richards, DVM