Page 1208 - Problem-Based Feline Medicine

1200 PART 15 CAT WITH EYE PROBLEMS

Protein and white cells (hypopyon) may also be pres-
DISEASES CAUSING A RED GLOBE: ent in the anterior chamber.
THE RED ANTERIOR CHAMBER
Hyphema may appear as a diffuse reddish discolor-
ation of the anterior chamber from free red cells. Fibrin
HYPHEMA ASSOCIATED WITH may be present as a result of hemorrhage, resulting in
TRAUMA* OR INFLAMMATION*
straw-colored strands or masses in the anterior cham-
ber, or there may be a combination of free red cells and
Classical signs
fibrin.
● The anterior chamber may be full of blood
The anterior chamber may appear black when there
and bright red in color.
has been a severe bleed.
● The eye may appear black, if bleeding is
very severe. The adnexa may show signs of trauma, including
● Signs of trauma with scleral and scleral and sub-conjunctival hemorrhage.
subconjunctival hemorrhage may be
If bleeding disorders are present, mucous membranes
present.
and skin may have small hemorrhages (petchia) or
● Bleeding disorders may have signs of
blotchy hemorrhages (echymoses).
hemorrhage on mucous membranes and
skin.
Diagnosis
Pathogenesis Diagnosis is based on the appearance of the anterior
chamber.
Hyphema (blood in the anterior chamber) occurs
because of trauma to the iris and/or ciliary body. Ocular ultrasound is useful as an adjunct where the
anterior chamber cannot be visualized. Check that the
The blood may be diffuse, filling the anterior cham-
spatial arrangements within the eye are normal, such as
ber, which appears bright red, or consist of a focal
depth of the anterior chamber, position and thickness of
accumulation of red cells. If focal, the eye may also
the iris, position and density of the lens, density of the
appear cloudy because of leakage of protein and white
vitreous. Also check for signs of retinal detachment and
cells (hypopyon).
the integrity of the scleral wall.
Any inflammatory disease of the iris can cause leak-
If there are no signs of trauma, uveitis or neoplasia,
age of blood products into the anterior chamber. This
assess platelet number and function, and clotting
can range from fibrin without significant numbers of
times.
accompanying red cells, to frank hemorrhage (hyphema).
Hyphema may also occur secondary to chronic uveitis,
Treatment
when pre-iridal fibrovascular membranes (new
blood vessels) develop on the iris surface. These are In severe cases of hemorrhage, some veterinary oph-
fragile and may hemorrhage. thalmologists inject tissue plasminogen activator
(TPA 0.1 mg usually diluted in 0.3 ml of diluent) into
Hyphema may occasionally occur secondary to sys-
the anterior chamber, as it breaks down fibrin which
temic neoplasia, particularly lymphosarcoma, as the
helps to disperse the clot. Its use is controversial, and
blood vessel endothelial walls are disrupted.
should not be used where there is trauma to the iris root,
In bleeding states such as rodenticide poisoning or throm- as this may cause a re-bleed.
bocytopenia, the anterior chamber may fill with blood.
Topical 1% prednisolone acetate drops (q 8 h) are
used to reduce inflammation and minimize iris adhe-
Clinical signs sions (synechia).
Hyphema may appear as a focal accumulation of red Systemic corticosteroids such as prednisolone (1 mg/kg
cells attached to the iris or free within the aqueous. q 12–24 h), are also used to minimize inflammation