Page 1127 - Cote clinical veterinary advisor dogs and cats 4th

Iris Abnormalities 563

PROGNOSIS & OUTCOME PEARLS & CONSIDERATIONS Technician Tips
Young animals often have intussusception
Comments
VetBooks.ir of intussusception For each patient, the risk of recurrence must causes. Therefore, the presence of intus- Diseases and Disorders
secondary to bacterial, viral, and/or parasitic
• Depends on cause, location, and duration
be weighed against the risk of complications
○ Good if fluid and electrolyte abnormali-
susception is a signal to institute appropriate
ties are corrected and there is immediate
surgical intervention associated with enteroplication: medical hygiene measures (e.g., gloving and
• The decision to perform enteroplication is
gowning when handling patient, isolation when
○ Patients with proximal GI tract intus- based largely on whether an underlying cause necessary).
susception, generalized peritonitis, or that can be corrected has been identified.
underlying malignant intestinal neoplasia • If enteroplication is performed, create gentle SUGGESTED READING
have a worse prognosis. loops along entire length of small intestine Burkitt JM, et al: Signalment, history and outcome
• Severe complications have been associated (from duodenocolic ligament to ileocolic of cats with gastrointestinal tract intussusception:
with enteroplication, but recurrence may be junction); place sutures 5-10 cm apart. 20 cases (1986-2000). J Am Vet Med Assoc
seen if not plicated. • Spontaneous reduction of intussusception has 234:771-776, 2009.
been reported in dogs; however, recurrence AUTHOR: Lori Ludwig, VMD, MS, DACVS
that requires surgical intervention may occur. EDITOR: Elizabeth A. Swanson, DVM, MS, DACVS

Iris Abnormalities Client Education
Sheet

BASIC INFORMATION • PPMs: heritable cause suspected in basenjis, ■ Adjacent iris; typically benign, inciden-
Pembroke Welsh corgis, chow chows, mas- tal finding
Definition tiffs, and others ■ Anterior lens; often associated with
Iris abnormalities include any change in the Clinical Presentation anterior capsular cataracts
color, character, or appearance of the iris, ■ Corneal endothelium; associated with
including acquired changes secondary to ante- DISEASE FORMS/SUBTYPES various degrees of corneal scarring and/
rior uveitis, neoplasia, ocular melanosis or cyst • Uveitis (p. 1023) or edema
formation, and developmental changes (e.g., • Uveal neoplasia (p. 559) ■ Iris sheets; most severe form (sheet of
persistent pupillary membranes [PPMs]). Other • Uveal cysts tissue bridging pupil); associated with
relevant definitions include those for rubeosis • PPMs vision impairment (rare)
iridis (blood vessel formation on the surface of • Iris cysts
the iris) and synechia (adhesion of iris-to-cornea HISTORY, CHIEF COMPLAINT ○ Variably pigmented spherical masses in
[anterior] or iris-to-lens [posterior]). Varies, depending on underlying cause; owner anterior chamber
may report signs associated with any of the ○ Cysts can be transilluminated or
Synonyms following: retroilluminated.
Uveal disease, ocular melanosis (once called • Anterior uveitis
pigmentary glaucoma) • Uveal neoplasia Etiology and Pathophysiology
• Ocular melanosis Depend on underlying cause:
Epidemiology ○ Darkening of the iris • The uveal tract (or vascular layer) of the eye
SPECIES, AGE, SEX ○ ± Cloudy/hazy appearance to the eye in is composed of the iris, ciliary body, and
• Dogs and cats cases of secondary glaucoma choroid. The iris is the most anterior of these
• Anterior uveal neoplasia usually is seen in • Uveal cysts and is a thin diaphragm containing blood
middle-aged to older animals. • PPMs vessels, connective tissue, melanocytes, and
• Ocular melanosis is seen in Cairn terri- ○ Usually incidental finding two muscles (iris sphincter and iris dilator).
ers and does not demonstrate age or sex ○ ± Cloudiness of eye if attached to cornea In the center of the iridal diaphragm is a
predisposition. or lens circular aperture, the pupil.
• Uveal cysts are most frequently found in • Anterior uveitis (p. 1023)
middle-aged to older animals (rare in cats). PHYSICAL EXAM FINDINGS • Uveal neoplasia (p. 559)
• PPMs are congenital; pupillary membranes • See History, Chief Complaint above. • Ocular melanosis: inherited thickening and
atrophy by 6 weeks of age in most puppies, • Ocular melanosis: any or all of the following: pigmentation of the iris caused by increased
but if not, PPMs may be detected in all age ○ Dark brown thickening of the iris root/ melanocytes and (to a lesser extent) melano-
groups (rare in cats). base phages, with release of pigmented material
○ Episcleral/scleral pigment plaques into the aqueous humor and pigment
GENETICS, BREED PREDISPOSITION ○ Release of pigment into aqueous humor, deposition in the episclera/sclera ± posterior
• Uveal melanoma: suspected genetic predis- with pigment deposition in aqueous segment. Secondary glaucoma can result from
position in the Labrador retriever, golden drainage pathways and on lens capsule extensive pigment deposition in the aqueous
retriever, and German shepherd. ○ Pigmentation of the tapetal fundus ± on drainage pathways.
• Ocular melanosis: inherited, probably the surface of the optic disk • Uveal cysts
autosomal dominant condition in Cairn ○ Secondary glaucoma in severe cases • PPMs: nonvascular remnants of the tunica
terriers • PPMs: any or all of the following: vasculosa lentis, which appear as iris strands
• Uveal cysts: predisposed breeds include ○ Single or multiple fine strands of iris tissue or sheets originating in the iris collarette
golden retrievers, Labrador retrievers, Boston originating from the iris collarette and (midway point between iris base and pupil-
terriers, Great Danes, rottweilers. inserting on: lary margin). PPMs extend across the iris

www.ExpertConsult.com