Page 1278 - Problem-Based Feline Medicine

1270 PART 15 CAT WITH EYE PROBLEMS

Systemic signs can involve many other organs, espe- ● Breakdown of the blood–aqueous barrier in anterior
cially the lungs, brain, nasal cavity, as well as the peri- uveitis.
orbital tissues, lymph nodes, bones, toenails and skin. ● Abnormally high concentrations of serum lipids,
which can be secondary or primary hyperlipidemia.
Diagnosis Lipemic aqueous is idiopathic in Burmese cats asso-
ciated with hyperlipidemia.
A tentative diagnosis is based on the presenting signs
of a cat with rapidly progressive, usually bilateral
chorioretinitis, progressing to anterior uveitis, with
Clinical signs
signs of other systemic disease, and occurring in a geo-
graphic area where such fungal disease is known to Typically there is a diffusely and uniformly cloudy
occur. anterior chamber. The aqueous appears as if it is full
of milk.
Imaging techniques can be used to obtain more sup-
portive evidence of a deep fungal infection: Usually the iris, pupil and tapetal reflex can still be
● Thoracic radiography to demonstrate pulmonary visualized.
granulomas.
Lipemic aqueous is often unilateral and may be sud-
● Nasal cavity radiography.
den in onset.
● Ocular ultrasound; signs of retinal detachment.
Occasionally it is associated with cats that have uveitis
Confirmation of the diagnosis is based on the demon-
caused by systemic diseases such as toxoplasmosis,
stration of the respective organism in:
FIP, fungal infections, when they have hyperlipidemia
● Cerebrospinal fluid.
caused by a high-fat content in the diet.
● Samples taken by centesis of vitreous or subretinal
exudate.
● Histopathology of enucleated globes.
Diagnosis
● Bone marrow biopsy samples (histoplasmosis).
A tentative diagnosis is based on clinical signs.
Serological tests can be performed, looking for ele-
vated antibodies (blastomycosis, histoplasmosis, coc- A definitive diagnosis is based on biochemical analy-
cidiodomycosis). sis of aqueous centesis samples and demonstration of
high serum lipid concentrations. Lipid electrophore-
tograms may be performed on the sample.
LIPEMIC AQUEOUS
Diagnosis of the underlying cause should be pur-
sued, if lipemic acqueous is not in a predisposed breed
Classical signs
such as the Burmese. If it is the result of a systemic dis-
● Eye may suddenly become very cloudy ease combined with a high-fat diet, the underlying dis-
with a “milky appearance”. ease should be identified (see The Cat With Abnormal
● Unilateral or bilateral. Iris Appearance, page 1294 and With Retinal Disease,
● Idiopathic in Burmese cats associated with page 1186).
hyperlipidemia.
● May occur in cats with uveitis that are on a
high-fat diet. Treatment

Reduce plasma lipid concentrations using a low-fat diet.
Treat other underlying medical problems, which
Pathogenesis
are associated with hyperlipidemia such as diabetes
High concentrations of lipid can enter the anterior mellitus, and systemic diseases causing uveitis (see The
chamber from the uveal vessels if there is either: Cat With Abnormal Iris Appearance, page 1294).