Page 349 - Small Animal Internal Medicine, 6th Edition

CHAPTER 21
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Disorders of the Trachea

and Bronchi

GENERAL CONSIDERATIONS epithelium (Fig. 21.1) and decrease mucociliary clearance.
Pneumonias are discussed further in Chapter 22.
Common diseases of the trachea and bronchi include canine Many clients have the misunderstanding that kennel
infectious respiratory disease complex (CIRDC), canine cough equals infection with Bordetella bronchiseptica. They
chronic bronchitis, feline bronchitis, collapsing trachea, and believe that the “kennel cough” vaccine (meaning, a Borde-
allergic bronchitis. Oslerus osleri infection is an important tella vaccine) prevents the disease and that antibiotics should
consideration in young dogs. cure the disease. They are confused by conflicting informa-
Other diseases may involve the airways, either primarily tion about canine influenza virus infections. Some have read
or concurrently with pulmonary parenchymal disease. These about devastating pneumonia, some have been told by
diseases, such as viral and bacterial pneumonia, other para- boarding facilities that they must vaccinate their dog before
sitic infections, and neoplasia are discussed in Chapter 22. they can use the facility, and some have been told by their
Feline bordetellosis can cause signs of bronchitis (e.g., cough) veterinarian that vaccination is not indicated.
but is more often associated with signs of upper respiratory An effective means of educating clients is to emphasize
disease (see the section on feline upper respiratory infection the similarities between CIRDC and colds and flu in people
in Chapter 15) or bacterial pneumonia (Chapter 22). (Box 21.2). The human medical profession has made strong
efforts to educate the public on influenza in the context of
vaccination, and colds in the context of the overuse of anti-
CANINE INFECTIOUS RESPIRATORY biotics. Further, most people have direct personal experience
DISEASE COMPLEX, INCLUDING with colds and flu.
CANINE INFLUENZA In both CIRDC and “colds and flu,” many different agents
are involved. Being infected with one agent does not pre-
Etiology and Client Communication clude being infected with another. A person is more likely to
Challenges develop infection if he, she, or family members regularly find
CIRDC, also known as canine infectious tracheobronchitis or themselves in group settings (e.g., daycare, working environ-
“kennel cough,” is a highly contagious, acute disease involv- ments with large staff, interaction with the public), just as
ing the airways. In most dogs, CIRDC is self-limiting, with dogs are more likely to be infected with frequent exposure
resolution of clinical signs in approximately 2 weeks. Many to other dogs (e.g., boarding or grooming facilities, dog
different viral and bacterial pathogens can cause this syn- parks, dog shows and trials, pet stores, shelters). Most people
drome (Box 21.1). The role of Mycoplasma spp. in respiratory and dogs recover without antibiotics or supportive care, and,
infection of any kind is likely complex, with frequent isola- in fact, viruses will not respond to antibacterial drugs, but
tion of organisms from apparently healthy individuals. some people and dogs develop pneumonia and require
However, several studies strongly support a role for Myco- aggressive treatment. Rarely, people and dogs die from their
plasma cynos, in particular, in CIRDC. Co-infection with infection or its consequences. Vaccines for specific agents
two or more of the organisms listed in Box 21.1 is common involved in CIRDC do not prevent infection, and none is
and may result in more severe clinical signs. completely effective in preventing signs, just as the influenza
Some dogs infected with organisms of CIRDC will vaccine does not prevent all infections or signs in people.
develop pneumonia. The pneumonia can be a direct effect of People and dogs are more likely to become seriously ill if
the CIRDC organism, particularly with infections with B. they are compromised in some way before infection, but
bronchiseptica and canine influenza. Secondary bacterial sometimes a particularly virulent strain of organism will
infection can also occur, enabled by damage to host defenses. arise with severe consequences for even healthy people or
For instance, Bordetella organisms infect ciliated respiratory dogs.

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