Page 1220 - Problem-Based Feline Medicine

1212 PART 15 CAT WITH EYE PROBLEMS

Look at the conjunctiva for changed appearance. Pathogenesis
Examine the associated tissues as problems may arise Herpesvirus is one of the most common causes of acute
from the eyelids, cornea, orbit or teeth. and chronic ocular discharge in cats.
Check the summary table for diseases arising from Infection is caused by feline herpes virus-1 (FHV-1),
these tissues. a member of the subfamily Alphaherpesviridae.
Serologically distinct varieties have been isolated from
non-domestic cats. The virus is also commonly called
WHAT? feline rhinotracheitis virus (FVR).
The appearance of the discharge will help localize The disease is more frequent in kittens, particularly
the problem. those from catteries with carrier cats, pet shops and
shelters.
Serous discharge is usually associated with eyelid
agenesis, corneal disease, allergic conditions or The course of the disease is usually 10–14 days.
blocked tear ducts.
Histologically, complete epithelial necrosis occurs,
Mucoid and mucopurulent discharge is more com- accompanied by a polymorphonuclear cell infiltrate.
mon with infections of the conjunctiva, eyelid or orbit.
A chronic carrier state may persist in older cats and
Infectious diseases are the most common cause of ocu- recurrence of viral shedding and/or signs is common.
lar discharge and changed conjunctival appearance. This may be because the FHV-1 virus does not stimu-
late effective local immunity.
Diagnosis is based on the history, clinical examination,
cytology, biopsy, laboratory tests for infectious diseases
and radiology of teeth, sinuses and nasal cavity in cases Clinical signs
with orbital disease.
The earliest sign of classical herpesvirus infection is
paroxysms of sneezing or salivation. This is usually
seen in kittens and cats that have not been immunized.
DISEASES CAUSING OCULAR
DISCHARGE OR CHANGED In young cats, systemic signs of upper respiratory
CONJUNCTIVAL APPEARANCE: disease with anorexia, pyrexia and depression are
CONJUNCTIVAL CAUSES OF OCULAR common.
DISCHARGE AND CHANGED
CONJUNCTIVAL APPEARANCE Tracheal and bronchial inflammation may result
in coughing and dyspnea, and occasionally bacterial
pneumonia occurs in kittens.
HERPES VIRUS CONJUNCTIVITIS***
Acute conjunctivitis manifested by hyperemia and
chemosis is seen at the same time as the respiratory
Classical signs
signs.
● Paroxysms of sneezing or salivation.
Prolapse of the third eyelid may occur as part of the
● Hyperemia and chemosis of the
inflammatory process in the eye.
conjunctiva, usually bilateral.
● Serous to mucopurulent ocular and nasal Serous ocular discharge is seen in the acute phase and
discharge. this rapidly progresses to a seromucous and muco-
● Conjunctival adhesions obstructing puncta purulent discharge.
of tear duct.
In young cats, ulceration may occur in the buccal
mucosa and on the tongue.
See main reference on pages 7, 1237 for details (The
Cat With Acute Sneezing or Nasal Discharge and The The ocular changes are usually bilateral, but may be
Cat With Abnormalities Confined to the Cornea). unilateral initially or in older cats.