Page 1277 - Problem-Based Feline Medicine

61 – THE CAT WITH A CLOUDY EYE 1269

Some cats present with exophthalmos (eye bulging Ocular ultrasound can be used to detect retinal
forward), where there has been an extension of the dis- detachment when anterior chamber flare, cataract or
ease from the sinuses and nasal cavity into the orbital vitreal flare prevents ophthalmoscopic examination of
tissues. the fundus. It is also used in cases of exophthalmos to
examine, and do ultrasound-guided biopsies of the
In cases with nasal infection, there may be a muco-
orbital tissue.
purulent discharge with sneezing. Distortion and
swelling over the bridge of nose, or a polyp-like
mass projecting from the nasal cavity are present in
OTHER SYSTEMIC FUNGAL INFECTIONS
70% of cats with the respiratory form.
(BLASTOMYCES DERMATITIDIS, CANDIDA
Chronic skin granulomas may be present. Skin ALBICANS, COCCIDIOIDES IMMITIS,
lesions consist of papules or nodules varying from HISTOPLASMA CAPSULATUM)
0.1–1 cm in diameter. Lesions may ulcerate and exude
serous fluid, or remain as intact nodules. Classical signs
Cats with disseminated disease may show neurological ● Chorioretinitis progressing to anterior
signs. uveitis (cloudy eye) and endophthalmitis,
in a geographical area where fungal
Cats may present with chronic nasal or skin disease,
infections occur.
and the ocular involvement is identified secondarily on
● Vision loss and reduced pupil light
physical examination. Cats may also be presented pri-
reflexes.
marily for the ocular signs, where the owner has seen
● Other organ system disease, e.g. renal,
the development of a cloudy eye and the cat has gone
CNS, nasal cavity.
blind.
See the main references on pages 1176, 1300 and 1283
Diagnosis
for details (The Blind Cat or Cat With Retinal Disease,
A tentative diagnosis is based on typical clinical The Cat With Abnormal Iris Appearance and The Cat
signs of nasal or skin disease and concurrent ocular With Abnormal Pupil Size, Shape or Response).
signs. The presence of small swollen brownish dis-
colored areas in the retina suggests fungal disease.
The frequency of occurrence of individual fungal Clinical signs
diseases in the geographical area helps establish a ten-
Most intra-ocular fungal infections cause similar
tative diagnosis.
ocular signs.
Cytology can be very useful in the diagnosis of C. neo- ● Choroidal granulomas are the most characteristic
formans. Demonstration of the organism can be made sign on fundoscopy, and appear as a raised area of
via anterior chamber centesis or by fine-needle tapetal hyporeflectivity, or small swollen brownish
biopsy (using a 25-gauge needle) taken from the sub- discolored areas in the retina.
retinal space. The sample is best stained with new methy- ● A generalized chorioretinitis and secondary
lene blue, Indian ink or Diff-Quick. retinal detachments, with ballooning of the retina
into the vitreous.
Serology to detect capsule antigen is sensitive using
● Optic neuritis may be present, seen as a red,
serum, CSF fluid or urine.
swollen optic nerve that is hyperemic.
Histopathology from tissue biopsies demonstrates the ● Anterior uveitis seen as cloudy, red eye with cor-
organism. neal edema, hypopyon and inflamed conjunctiva.
Radiology of the nasal cavity, sinuses and chest may be Affected cats show varying degrees of blindness,
useful in cases that do not demonstrate nasal or skin signs. depending on the severity of the ocular infection.