Page 31 - Problem-Based Feline Medicine

3 – THE CAT WITH SIGNS OF CHRONIC NASAL DISEASE 23

– Commonly used antibiotics include doxycy- ● Leukotriene antagonists like zafirlukast
cline, cephalexin, amoxicillin-clavulanic acid, (Accolade; 0.5–1.0 mg/kg PO q 12–24 h) or mon-
clindamycin, enrofloxacin and azithromycin. telukast (Singulaire, 0.25–1.0 mg/kg SID) help by
Amoxicillin-clavulanic acid, metronidazole, clin- reducing pain and inflammation, and may be effec-
damycin and azithromycin are good first choices. tive in some cats.
– Doxycycline and metronidazole may be advanta-
If signs persist despite antibiotics, surgical removal of
geous because they have an immunomodulating
chronically inflamed tissue via a rhinotomy is some-
effect which may help reduce inflammation.
times successful.
– Azithromycin is attractive because of the alter-
● Surgery is generally more successful for chronic
nate day dosing, and in cattery and breeder situ-
sinusitis with radiographic evidence of fluid in the
ations the pharmacokinetics allow twice weekly
sinuses, than for chronic rhinitis. Opening the fora-
dosing (q 72 h).
men between the sinus and nasal passages facili-
● One regime that is effective in many cats is
tates drainage of the sinus.
enrofloxacin (Baytril; 2.5 mg/kg q 12 h for 30
● Surgery involves turbinectomy and/or ablation
days) together with azithromycin (Zithromax;
of the frontal sinuses. For frontal sinus ablation,
20 mg QD for 30–45 days).
the sinuses are curetted out, the periosteum
– Fluroquinolones, particularly enrofloxacin may
removed, and the cavity filled with subcutaneous
be associated with retinal degeneration and
abdominal fat or methylmethacrylic.
blindness, especially at high doses, and many
ophthalmologists avoid using these drugs. Interferon alone or with ATZ (zidovudine) or PMEA
● Cats with Pseudomonas cultured from the sinuses (phosphonomethoxyethyl adenine) may help in FeLV-
may respond to a long course of carbenicillin. and FIV-infected cats to stimulate immunity and
● If signs return rapidly after stopping antibiotics, improve signs.
long-term antibiotics administered once daily at
half the total daily dose may help control signs in
Prognosis
some cats. However, resistance to antibacterial
action commonly occurs, and a better strategy is a Most cats have a good quality of life, although
longer course of antibiotics based on culture and signs often persist and must be controlled with
sensitivity using dosages suitable for osteomyelitis, antibiotics.
followed by a course of antibiotics when signs
relapse.
Prevention
● Intranasally administered antibiotics such as
gentomicin ophthalmic drops sprayed into each Regular vaccination to prevent feline calicivirus and
nostril twice daily for 30 days may help, if the cat herpesvirus infection is recommended, because most
will tolerate them. chronic bacterial rhinitis occurs secondary to upper res-
● Acetylcysteine (Mucomyst) helps to liquefy piratory viral infection.
nasal secretions when used with nebulization, but
may be expensive for long-term use.
NEOPLASIA**
● In some cats, intermittent flushing of the nasal
cavity under anesthesia (with tracheal intubation)
Classical signs
can be useful in controlling clinical signs.
● Occasionally, cats will tolerate local instillation of ● Progressively worsening chronic sneezing
saline drops in the nasal cavity. This stimulates a and snuffling.
sneeze response and encourages evacuation of ● Purulent or blood-tinged nasal discharge,
mucus. which may temporarily respond to antibiotics.
● Individual cats may show improvement with anti- ● Epiphora, ± signs of retrobulbar pressure,
histamines especially second-generation antihista- e.g. exophthalmos.
mines such as loratidine (Claritin; 2.5 mg/day) ● Nasal obstruction, and occasionally facial
because of their anti-inflammatory effects as well distortion.
as their ability to dry up excessive mucus.