Page 30 - Problem-Based Feline Medicine

22 PART 1 CAT WITH UPPER RESPIRATORY TRACT SIGNS

These changes decrease mucociliary clearance from the misdiagnosed as bacterial infection, because of the
nose, and cause nasal and sinus obstruction. presence of neutrophils and bacteria.
● Structural changes include necrosis of the nasal ● To exclude neoplasia, material must be collected via a
epithelium, squamous metaplasia, osteolysis of traumatic flush using a stiff polypropylene catheter
the turbinates, and mucosal gland hypertrophy. attached to a syringe, or via a biopsy using a pinch
● The result is decreased density of cilia and biopsy technique through the nares, or a core biopsy
increased viscosity of mucus. This decreases via a trephine, or surgical biopsy via rhinotomy.
mucociliary clearance from the nose and ● Cytological examination of the nasal discharge or
sinuses. atraumatic nasal flush is inadequate to exclude
● Persistent thickening of the lining tissues of the neoplasia as a cause of the secondary bacterial
nasal cavity and sinuses leads to nasal and sinus infection.
obstruction, predisposing to chronic sinusitis. ● Surgical rhinotomy and biopsy may be necessary
● The normal opening between the nasal cavity and to exclude neoplasia when the history and radi-
frontal sinuses is small in cats, and is relatively eas- ographic findings are equivocal.
ily obstructed.
Negative Cryptococcus titer.
Organisms most frequently isolated are those that
Check FeLV and FIV status.
comprise the normal flora of the nose (e.g.
Staphylococcus, Streptococcus, Pseudomonas).
Differential diagnosis
Cats with feline immunodeficiency virus (FIV) or
feline leukemia virus (FeLV) may be more susceptible. Neoplasia produces similar signs, but duration of signs
is usually less than 6 months, and cats are often older
than 10 years of age. Radiographic lesions are often
Clinical signs unilateral or asymmetric, whereas chronic rhinitis
tends to be bilaterally symmetrical.
Chronic sneezing, snuffling and mucopurulent nasal
discharge is often present for months or years. Cryptococcosis produces similar signs, although 70% of
cats with nasal involvement have distortion over the
Stertorous respiration, (snoring) or stridor (whistling), bridge of the nose, or a polyp-like mass visible in the
may be audible from the nasal area. nasal cavity.
Occasionally, nasal distortion is present when signs ● Only rarely do cats with chronic bacterial infec-
have been present for years. tion have nasal distortion, and this is usually only
after signs have been evident for years.
● Diagnosis of cryptococcosis is based on finding evi-
Diagnosis dence of the organism on cytology, histology or
serology.
History of chronic snuffling following acute upper res-
piratory tract infection.
Treatment
Radiographic findings
Treatment requires prolonged antibiotic therapy for
● Usually there is loss of lucency in the nasal cavity
1–4 months. Many cats cannot be cured, and nasal dis-
(fluid density) and often in the frontal sinuses.
charge and sneezing persist, requiring repeated therapy
● Radiographic changes are usually bilaterally sym-
when signs are exacerbated. Different combinations of
metrical.
therapy work better in individual cats.
● Osteolysis of the turbinates and/or nasal septum
● Use broad-spectrum antibiotics, or base choice
may be evident.
on culture and sensitivity. Because of the large
Cytology or histology reveals many neutrophils with number of normal flora in the nasal cavity, culture,
intra- and extracellular bacteria, and no evidence of and therefore sensitivity results, are hard to inter-
Cryptococcus neoformans or neoplastic cells. pret. The best antibiotics to use are broad spectrum
● Beware of similar cytologic findings with neopla- with efficacy against anaerobes, and that penetrate
sia, and sometimes cryptococcosis. Often neoplasia is bone and cartilage.