Page 287 - Small Animal Internal Medicine, 6th Edition

CHAPTER 15 Disorders of the Nasal Cavity 259

the cat has increased risk of exposure to infection. Detection bacterial rhinitis, and it is difficult to make a definitive diag-
of FHV and FCV antibodies in the serum of cats is predictive nosis because of the diverse flora in the normal nasal cavity.
VetBooks.ir of susceptibility to disease and therefore may be useful in Microscopic evidence of neutrophilic inflammation and bac-
teria is a nonspecific finding and is found in the majority of
determining the need for revaccination (Lappin et al., 2002).
Queens should be vaccinated before breeding.
swabs or nasal mucosal biopsy specimens collected deep
Subcutaneous modified-live vaccines for FHV and FCV animals with nasal signs (Fig. 15.1). Bacterial cultures of
are safe but can cause disease if introduced into the cat by within the nasal cavity can be performed. The growth of
the normal oronasal route of infection. The vaccine should many colonies of only one or two organisms may represent
not be aerosolized in front of the cat. Vaccine inadvertently significant infection. Growth of many different organisms or
left on the skin after injection should be washed off imme- small numbers of colonies probably represents normal flora.
diately before the cat licks the area. The microbiology laboratory should be requested to report
Modified-live vaccines should not be used in pregnant all growth. Specimens for Mycoplasma cultures should be
queens. Killed products are available for FHV and FCV that placed in appropriate transport media for culture using spe-
can be used in pregnant queens. Killed vaccines have also cific isolation methods. Beneficial response to antibiotic
been recommended for cats with feline leukemia virus therapy is often used to support a diagnosis of bacterial
(FeLV) or feline immunodeficiency virus (FIV) infection. involvement.
Modified-live vaccines for FHV and FCV are also avail-
able for intranasal administration. Signs of acute URI occa- Treatment
sionally occur after vaccination. Attention should be paid to The bacterial component of nasal disease is treated with
ensure that panleukopenia is included in the intranasal antibiotic therapy. If growth obtained by bacterial culture is
product or that a panleukopenia vaccine is administered believed to be significant, sensitivity information can be used
subcutaneously. in selecting antibiotics. Anaerobic organisms may be
Vaccines against Bordetella or Chlamydophila are recom- involved. Broad-spectrum oral antibiotics that may be effec-
mended for use only in catteries or shelters where these tive include amoxicillin (22 mg/kg q8-12h) or clindamycin
infections are endemic. Infections with Bordetella or Chla- (10 mg/kg q12h). Doxycycline (5 mg/kg q12h or 10 mg/kg
mydophila are less common than FHV and FCV infection, q24h; always followed by a bolus of water) is often effective
and disease resulting from Bordetella infections occurs pri- against Bordetella and Mycoplasma organisms.
marily in cats housed in crowded conditions. Furthermore, For acute infection or in cases in which the primary etiol-
these diseases can be effectively treated with antibiotics. ogy (e.g., foreign body, diseased tooth root) has been elimi-
nated, antibiotics are administered for 7 to 10 days. Chronic
Prognosis infections require prolonged treatment. Antibiotics are
The prognosis for cats with acute URI is good. Chronic
disease does not develop in most pet cats.

BACTERIAL RHINITIS

Acute bacterial rhinitis caused by Bordetella bronchiseptica
occurs occasionally in cats (see the section on feline URI)
and rarely in dogs (see the section on canine infectious respi-
ratory disease complex in Chapter 21). Mycoplasma spp. and
Streptococcus equi, subsp. zooepidemicus, also may act as
primary nasal pathogens. In the vast majority of cases, bacte-
rial rhinitis is a secondary complication and not a primary
disease process. Bacterial rhinitis occurs secondarily to
almost all diseases of the nasal cavity. The bacteria that
inhabit the nasal cavity in health are quick to overgrow when
disease disrupts normal mucosal defenses. Antibiotic therapy
often leads to clinical improvement, but the response is
usually temporary. Therefore management of dogs and cats
with suspected bacterial rhinitis should include a thorough
diagnostic evaluation for an underlying disease process, par-
ticularly when signs are chronic. FIG 15.1
A photomicrograph of a slide prepared from a nasal swab
Diagnosis of a patient with chronic mucopurulent discharge shows the
typical findings of mucus, neutrophilic inflammation, and
Most dogs and cats with bacterial rhinitis have mucopuru- intracellular and extracellular bacteria. These findings are
lent nasal discharge. No clinical signs are pathognomonic for not specific and generally reflect secondary processes.