Page 1226 - Problem-Based Feline Medicine

1218 PART 15 CAT WITH EYE PROBLEMS

should be cleaned with saline, or an irrigating eye Two or three freeze–thaw cycles using liquid nitrogen
wash. A small scalpel blade or spatula is then used to will produce the best results. The eyelid and conjunc-
scrape the surface of the lesion. Carefully wipe the tiva has a very rich blood supply, and heals rapidly after
tissue on the blade over a glass microscope slide, and cryo-destruction of tissue. Supportive therapy using
stain with a cellular stain. Neoplastic epithelial cells broad-spectrum ointments or drops, and regular, gentle
are large and often clumped, with large dark stain- cleaning helps the healing process, by preventing sec-
ing nuclei and prominent nucleoli with very small ondary bacterial infection. (See page 1070, The Cat
cytoplasm. Normal epithelial cells have a large amount With Lumps and Bumps.)
of pink cytoplasm, and a central small round nucleus.
Intralesional chemotherapy using cisplatin in oil
Fine-needle biopsy will demonstrate similar pathology adjuvant, or in plastic rods, has been used with some
to cytology specimens. Use a 22-gauge hypodermic success. Refer such cases to a trained oncologist. (See
needle and a 5-ml syringe. Push the needle into the page 1346).
lesion, and suck hard on the syringe. Let the plunger
go, and remove the needle from the lesion. Remove the
MYCOPLASMA CONJUNCTIVITIS**
needle from the syringe, and pull the plunger back so
that the syringe is full of air. Replace the needle on the
Classical signs
syringe, and blow the needle contents onto a micro-
scope slide. Spread this carefully with another slide, ● Usually mild conjunctivitis, unilateral or
and stain with a cellular stain. A similar pattern of cells bilateral.
will be seen as in the cytology sample. ● Serous ocular discharge becoming
mucopurulent.
Histopathology is more definitive but requires more
● Mild respiratory signs such as mild serous
invasive surgical techniques to remove a block of
nasal discharge.
affected tissue. Place tissue in 10% buffered formalin,
● Occasionally, thick white discharge across
and send to a laboratory for sectioning and examination.
conjuntiva (pseudomembrane).
Radiology of adjacent bones is important in cases
involving the medial canthal tissue and skin over the See the main reference on page 14 for details (The Cat
nose. Any secondary involvement of bony tissue gives With Acute Sneezing or Nasal Discharge).
a very poor prognosis.
Pathogenesis
Differential diagnosis Mycoplasma felis and Mycoplasma gatae are thought
to cause conjunctivitis in cats.
Granulating wounds can have a similar appearance.
Use cytology and fine-needle biopsy to differentiate if They may only be pathogenic when potentiated by
needed. Granulating wounds appear healthy, with uni- other organisms, for example Chlamydophila felis,
form redness and a smooth, moist cellular surface. and viruses such as herpes or calicivirus.

Infection causes a polymorphonuclear leukocyte
Treatment response in the conjunctiva.
The lesion may be excised if it is in a small focal Cytology may reveal small basophylic inclusion bod-
area. If the lesion is in the medial canthus, care ies, which are coccoid or coccobacillary, and are seen in
should be taken to try to preserve the lower puncta the periphery of the cytoplasm of the epithelial cells.
and nasolacrimal duct.
Mycoplasma organisms can be cultured in the laboratory.
Radiation therapy, either with direct beta-radiation, or
radioactive gold implants. Clinical signs
Cryosurgery is the most common method of treat- Usually, there is a unilateral or bilateral conjunctivi-
ment. There are many types of cryogens that are used. tis, with a serous discharge becoming mucopurulent.