Page 1227 - Problem-Based Feline Medicine

59 – THE CAT WITH OCULAR DISCHARGE OR CHANGED CONJUNCTIVAL APPEARANCE 1219

The conjunctiva may appear normal, or there may be Chlamydial conjunctivitis shows mild respiratory
a mild hyperemia and chemosis. signs of sneezing and nasal discharge. In acute cases,
the conjunctiva may show severe chemosis and hyper-
In more chronic cases, the conjunctiva may be thick-
emia, with a serous discharge rapidly changing to
ened with the formation of follicles, which develop
a mucopurulent discharge. Chronic cases show follicle
from focal areas of lymphoid cell stimulation.
formation in the conjunctiva. Cytology, fluorescent
Rarely, a pseudomembrane is formed, which consists antibody, and ELISA tests can be used to differentiate
of a thick white exudate covering the conjunctiva. chlamydial infections from mycoplasma.
Respiratory signs consist of sneezing with a serous Eosinophylic keratoconjunctivitis presents with a
nasal discharge. mucopurulent discharge, and there is a proliferative
inflammatory response of the conjunctiva and cornea.
Diagnosis The presence of eosinophils in a cytological prepara-
tion of the conjunctiva and cornea is supportive for this
Initial diagnosis is usually based on typical clinical
diagnosis. The condition responds to topical and sys-
signs of mild sneezing, with serous nasal, and mild
temic corticosteroids.
serous ocular discharge. Chronic cases develop con-
junctival follicles and on rare occasions a thick tena-
cious white pseudomembrane forms.
Treatment
Cytology may reveal small basophylic inclusion
Mycoplasma conjunctivitis responds rapidly to a
bodies, which are coccoid or coccobacillary, and are
wide range of antibiotics particularly tetracycline
seen in the periphery of the cytoplasm of the epithelial
and chloramphenicol. Tetracycline is more commonly
cells. There is a predominantly polymorphonuclear cell
used because this organism is frequently seen in asso-
response.
ciation with Chlamydophila felis infection.
Isolation of the organism can be done in most labora-
Respiratory and ocular signs will be suppressed by top-
tories from clean conjunctival swabs. It is important to
ical and systemic corticosteroids, but are not indicated
remove the discharges from the eye with sterile normal
for treatment.
saline solution or eye washes, prior to taking the sam-
ple, as this reduces the contamination from secondary
bacterial infections.
Prognosis
Differential diagnosis The prognosis is good as complications are rare.
Cases that are complicated by concomitant infection with
Allergic conjunctivitis will have a similar appearance
Chlamydophila felis or viruses may have a complicated
to mild cases of mycoplasma infection. There is usually
prognosis.
a poor response to antibiotic treatments. Most cases
have an allergy to insect bites, food, or the cats are
atopic. The best approach for control of the ocular signs Transmission
is by referral to a dermatologist or medical internist, so
Direct contact with affected animals. Infection is more
that the cause of the allergy can be established and the
prevalent in catteries and pet shops.
correct management instigated.
Airborne transmission occurs in confined spaces such
Herpetic keratitis usually presents with acute respira-
as catteries and pet shops.
tory signs, including sneezing, nasal discharge, pyrexia,
depression and anorexia. The conjunctiva shows
chemosis and hyperemia, and the ocular discharge is Prevention
more pronounced. Viral isolation and PCR tests may be
There is no effective vaccine.
helpful to differentiate herpesvirus from mycoplasma
infection, and there is usually an equivocal response to Good hygiene and separation of animals at risk from
antibiotic treatment. infected animals will reduce the incidence of infection.