Introduction: When you bring a dog into the vet that has a hoarse cough, there's a good chance that the problem is "kennel cough". But there aren't any simple in clinic tests that confirm this.
And we often hear the same hoarse cough with anything that causes irritation to the larynx or throat to include gagging on a stick or bone, acid reflux, being choked on a chain or leash, and maybe from sinus drainage from allergies. We also hear bronchial coughs with heartworm disease, heart disease, lung cancer, respiratory infections, and certain parasites. (sometimes the trauma of a trach tube during anesthetic procedures can cause similar symptoms)
So when your vet says your dog has kennel cough, he or she is making this diagnosis... in most cases... because he or she went through a thought process while examining your pet that goes something like this:
There isn't a murmur, congestion, or abnormal lower airway sounds so the problem is not likely to be heart disease, pneumonia, lung cancer etc.
This patient has been on heartworm preventive so it's unlikely to be heartworm disease.
The hoarsness of the cough is worse near the throat and when I squeeze on the throat I elicit a cough or gag reflex typical of laryngitis. So the problem is an irritated larynx either due to choking on some object, from reflux, or one of the upper respiratory germs that cause "kennel cough"
If there is a history of other dogs coughing in the house, neighbors dogs coughing, or an history of boarding or otherwise being exposed to other dogs within the last 10 days, this is a further and very big clue that this a a kennel cough case.
At this point your vet will either declare that this is probably kennel cough and
1. treat it as such
2. treat it as such but also treat for possible gastro intestinal reflux at the same time is this is suspected
3. and/or decide that there's enough suspicion or evidence to warrant further work up. Likely tests would include heartworm screening, radiographs, and a throat culture.
What is Kennel Cough?
Infectious tracheobronchitis or kennel cough is simply inflammation of the trachea (wind pipe) and/or the larynx (back of the oral cavity behind the base of the tongue where with a little luck food and water split off to go down the esophagus and air goes down the trachea. There are tonsils and other lymphoid tissues lining the larnyx that help prevent germs and irritants from getting into the airways.
A germ called bordetella causes contagious laryngitis ... espcially in puppies... and we have a vaccine available to gives your dog at least some immunity to this germ.
But guess what? Exposure to canine flu virus, adenovirus, distemper virus are often the cause. And sometimes the cause is due to canine reoviruses , and canine herpesvirus. Or, the cause could be from gram negative bacteria like Pseudomonas, E. coli, and Klebsiella. There is even evidence that the throat irritation can be due to various strains of equine flu virus'. Or any combination of the above. No wonder our bordetella vaccine doesn't give perfect immunity.
Stress and extremes of ventilation, temperature, and humidity apparently increase susceptibility to, and severity of, the disease.
Kennel cough disease is usually a mild, self-limiting disease but every once in a while may progress to pneumonia and death, especially in puppies or debilitated old dogs.
The illness spreads rapidly among susceptible dogs housed in close confinement including veterinary hospitals and kennels.
Clinical Findings and Diagnosis: The prominent clinical sign is paroxysms of a harsh, dry cough, which may be followed by retching and gagging.
The cough is easily induced by gentle palpation of the larynx or trachea.
Affected dogs demonstrate few if any additional clinical signs except for partial anorexia.
Body temperature and WBC counts usually remain normal.
Development of more severe signs, including fever, purulent nasal discharge, depression, anorexia, and a productive cough, especially in puppies, indicates a complicating systemic infection such as distemper or bronchopneumonia.
Stress, particularly due to adverse environmental conditions and improper nutrition, may contribute to a relapse during convalescence.
Tracheobronchitis should be suspected whenever the characteristic cough suddenly develops 5-10 days after exposure to other susceptible or affected dogs.
Usually severity diminishes during the first 5 days, but the disease persists for 10-20 days.
Testing: Appropriate tests, as mentioned in the introduction might include screening for heartworms and intestinal worms (part of the life cycle of intestinal worms involves larvae migrating through the lungs), chest and airway radiographs, and blood work. Also a culture and sensitivity testing.
Preferably, affected dogs should not be hospitalized because the disease is usually highly contagious (and also self-limiting).
Appropriate management practices, including good nutrition, hygiene, and nursing care, as well as correction of predisposing environmental factors, hasten recovery.
Treatment at our clinic consists of:
1. A controversial combination of short acting steroids - penicillin and gentocin antibiotics - atropine and B12. There are any number of academic objections to giving such a combination, but there's a reason I do it: it works well. About 20% of the patients stop coughing the next day and act like they're all better. Another 60-70% don't get all better in one day but they are noticeably improved, aren't as likely to get secondary infections, and feel better.
2. Doxycycline antibiotics to fight and prevent secondary bacterial infections.
3. Cough suppressants, cough syrups, and products to soothe the throat. I usually dispense "cough" tablets and recommend a small amount of vodka mixed with pancake syrup be given by mouth as needed
4. Cat lax: basically flavored vaseline meant for cats with hairballs. The vaseline might soothe the throat as it is swallowed, but the main reason for giving it is to evacuate the upper gi tract in case reflux is a factor.
5. Time; symptoms can last several weeks. Recheck only if not improving in a reasonable time, or if your dog stops eating for more than a day, has yellow nasal discharge, a chest rattle etc.
6. Client awareness that there are other causes of hoarse coughs.... sometimes re evaluation is in order.
Several brands of vaccines are available that give moderately successful prevention or at least reduce the severity of the disease. As of 2014, the newest vaccine for kennel cough is oral... a simple squirt in the mouth.
The success of all the available vaccines are limited but still worth giving and recommended... often required ... prior to boarding in commercial kennels, dog shows and so forth where the risk of exposure to the disease is common.
The vaccine works best if given several weeks prior to exposure.
Duration of protection from the vaccine starts to wane after about 6 months.