L6- Eye and Ear Non-infectious, infectious, neoplasia Flashcards
(30 cards)
Collie Eye Anomaly
Inherited bilateral ocular disorder
• Collies (rough and smooth coat) and Collie-related breeds • An inherited autosomal recessive trait; NHEJ1 gene
• Diagnostics: rapid genotyping PCR
• CHORDIAL HYPOPLASIA:
• Focally extensive to diffuse thinning and pallor
• COLOBOMA:
Gray or pink indentations (variably sized) that are
within or adjacent to the optic disk
• RETINAL DETACHMENT:
• Most often a sequela from coloboma
• Subretinal, intraretinal, or preretinal, intravitreal
hemorrhage
(depigmentation)
Congenital Glaucoma
Filtration angle is the exit point for vitreous flow
• Normally has trabecular meshwork
• Congenital (primary) glaucoma
• Due to goniodysgenesis, genetic defect
• Hypoplasia or dysplasia of filtration angle
• Almost exclusively in dogs
• Beagles, bassetts
anterior lens luxation, retinal atrophy and detachment, optic disc cupping
• Secondary (acquired) glaucoma
• Due to ocular or systemic disease
• Can occur in any species
• Causes increased intraocular pressure
• If untreated, can lead to buphthalmos, cataracts,
Retinal dysplasia
Abnormal retinal differentiation
• Jumbling of retinal layers
• Primary
• ”True” dysplasia – rare
• Collies, English Springer Spaniels
• Secondary
• RETINAL NECROSIS- MOST COMMON
• Due to viral or chemical insults
• BVD, bluetongue, herpes, parvo, FeLV
• Leads to retinal scarring
• Retinal folding
• Not a true dyslasia
• Growth of retina exceeds growth of sclera
Dermoid
Congenital lesions of cornea, conjunctiva, or
eyelids
• Focal skin-like differentiation
• Can cause irritation and keratitis or blepharospasm
• Normal tissue in abnormal location
• Unknown pathogenesis
• Likely hereditary in polled Hereford cattle
• Variably sized plaque of normal skin
• Often has hair
Equine recurrent uveitis
*THE MOST COMMON CAUSE OF BLINDNESS in horses
• More common in Appaloosas
• Likely a hypersensitivity reaction to an exogenous
antigen
• Leptospira interrogans serovar Pomona
• Substantial evidence; but not absolute
• Onchocerca cervicalis occasionally implicated
• Gets worse/more severe with each recurrent attack
• May initially be unilateral; will be bilateral eventually
• ANTERIOR UVEITIS
• Corneal edema, *LOW IOP, conjunctivitis, glaucoma rare
• Corneal vascularization, edema, posterior synechiae
Uveodermatologic syndrome
Autoimmune disease
• Targets uveal and dermal melanocytes – likely
tyrosinase
• Arctic breeds
• Eye lesions typically show first, then skin lesions
• Facial depigmentation and severe, bilateral
uveitis
• Panuveitis with secondary sequelae
• Retinal detachment, cataracts, anterior synechiae, glaucoma
• Dogs usually present with acute blindness
Pannus Keratitis
Progressive, bilateral, inflammatory disease of the cornea
• Common in GSD, can occur in others
• Most common in German shepherd dogs (GSD), but may
occur in any breed
• Immune mediated
• UV light may be role
• GSDs affected when young – rapid and severe
• 1-5 yo
• Animals affected later in life – less severe, slower progression
• 4-6 yo
• Red, vascularized, conjunctival lesion
• Starts at temporal limbus, moves central
• Forms bed of granulation tissue
• Fibrovascular plaque
Corneal ulceration
Defects in surface, epithelium or stroma of cornea
• Causes changes in vision or loss
• Many causes – infectious, trauma, entropion, drying, etc.
• Superficial
• Defect in epithelium
• Stromal ulcer
• Affecting stromal layer
• Can be superficial, mid, or deep
• Crater-like ulcer
layer at edge of cornea bulbi (end stage)
• Descemetocele
• Deepest ulcer – only thing holding cornea intact is endothelial
• Can lead to perforation of cornea and eventual phthisis
• Diagnostics: fluorescein stain
Retinal detachment
Occurs between pigmented
epithelium and photoreceptor
layers
• Accumulation of inflammation,
cells, debris, etc.
• Often a sequela
• Causes:
• Trauma with hemorrhage
• Hypertension
• Diabetes
• Infectious agents – fungal,
protozoal, algal
cataract
Permanent opacity resulting from increased
hydration of the lens
• Can be inherited, idiopathic, secondary to
glaucoma or diabetes
• Degeneration of capsular epithelium – loss of Na-K
dependent ATPase pumps
• Hydropic cell rupture
spontaneously diabetic dogs
• Diabetes
• Usually bilateral; develop in about 70% of
• Opaque lens
• May see blindness clinically
Gas bubble disease
Fish
• Due to supersaturation of water by a gas -
usually nitrogen
• Can occur in natural or tank scenarios
• Exophthalmia, gas bubbles in eyes
tissues
• Cataracts, anterior synechia, panophthalmitis
• Fish die due to asphyxiation
• Mechanical disruption of blood flow
• Gas leaves bloodstream to form emboli in tissues
chlamydial conjunctivitis
Caused by Chlamydia sp.
• Obligate intracellular bacteria
• Forms intracytoplasmic inclusions in epithelial cells • Chlamydial conjunctivitis in cats (C. felis)
• Always involves the eye, occasionally causing signs of rhinitis, with sneezing and nasal discharge
• Dogs: C. psittaci
• C. suis (pigs), C. psittaci (birds), and C. pecorum (cattle and sheep
C. caviae (guinea pigs; guinea pig inclusion conjunctivitis)
• Unilateral or bilateral conjunctival hyperemia, chemosis, and serous ocular discharge
ocular discharge
• Conjunctival swab/cytology
• Route of infection: direct contact
• Serous to mucopurulent conjunctivitis, nasal discharge, and sneezing
Infectious bovine keratoconjuctvitis
Caused by Moraxella bovis
• Virulence factors: Many hydrolytic enzymes causing ocular
injury
• Only two proteins have been linked to pathogenicity: pilin and
cytotoxin
• More severe in younger cattle
• Route of infection: nasal secretions, fomites, direct
contact
• Lacrimation, photophobia, blepharospasm
• Conjunctival chemosis
• Keratitis with corneal edema and ulcers
• If untreated will progress to deep ulcer and keratomalacia
• Can progress to anterior uveitis with thick mucopurulent
discharge
FHV-1 Keratitis
Caused by feline herpesvirus-1
• Most common cause of conjunctivitis and keratitis in • Route of infection: nasal, oral, conjunctival
• Herpesvirus damages mucosal epithelial cells
• Becomes latent in trigeminal ganglia
• Recrudescence with stressful events
• Many become lifelong carriers of virus
• Adults with reactivation
• Dendritic ulcers – can be unilateral or bilateral
• Conjunctivitis, blepharospasm, ocular discharge
domestic cats route during replication
canine infectious hepatitis
Caused by adenovirus type I
• Like endothelial cells of organs
• Edema, serosal hemorrhage
• Route of infection: oronasal
• Immune-mediated anterior uveitis
• Damage to endothelial cells à corneal
edema
Gallid Herpesvirus
Gallid herpesvirus-2
• Alphaherpesvirus
• Marek’s disease – lymphoproliferative
disease of chickens
• T-cell lymphoma
• Route of infection: inhalation of feather
dander
• Infection of feather follicle epithelium
• Virus is shed in feather dander, site of
complete viral replication
• Ocular lesions
• Discoloration of iris due to lymphoblastoid
infiltration
Ocular squamous cell carcinoma
Tumor of conjunctival epithelium of limbus,
nictitating membrane or eyelid
• Cattle > horse > cat > dog
• Origin sites: bulbar conjunctiva of limbus,
nictitating membrane, palpebral conjectiva of eyelid
• Horses: edge of third eyelid is most common site
• Cats: skin of eyelid
• Often see ulceration
• Risk factor – lack of periocular pigment
(Herefords), exposure to UV light
• Parotid lymph node is initial site of metastasis
• Variably sized, poorly demarcated, firm white
masses
Uveal melanoma
Tumor of melanocytes
• Most common intraocular tumor in dogs
• Behavior depends on location and species
• DOGS: anterior uvea = benign; lid margin =
benign; conjunctiva = malignant; limbus = benign; choroid = benign
• Can expand within the globe
• Can get secondary glaucoma
• Uveitis and hyphema
• Arise from skin of lids margin, conjunctiva,
anterior uvea, ciliary body
• Generally benign
• Expansile, pigmented nodules
Diffuse iris melanoma
Biological behavior of ocular melanomas
depends heavily upon species and
location
• CATS: Iris is most common
• Iris pigmentation, progresses to diffuse
hyperpigmentation
• Always have secondary glaucoma
• Metastasis can occur
• Diffuse iridial thickening,
hyperpigmentation with glaucoma
Intraocular Lymphoma
• Most common metastatic neoplasm in dogs
and cats
• Usually bilateral within uveal tract
• Can involve other eye structures
• Causes anterior uveitis with thickening of
uvea
• White to tan nodules
• Exophthalmos if tumor within the orbit
• Iridial color change and pallor from infiltrating
neoplastic cells
Meibomian Adenoma
Most common ocular neoplasm of dogs
• Similar to sebaceous adenoma in skin
• Tumor of Meibomian gland
• Produces oily substance that normally helps to stabilize tear film
• Lobular mass on eyelid margin, pink to
pigmented
• Can protrude outward or extend into eyelid
• Can see secondary keratoconjuctivitis if rubbing
cornea
feline post- traumatic ocular sarcoma
Malignant transformation of lens
epithelial cells
• Secondary lens rupture
• Locally invasive
• Sequelae to ocular trauma or severe
disease
• Initiating event, then 5-7 year dormancy
• Usually see extension along optic or
peripheral nerve to brain
• Can recur despite enucleation
• Globe filled with neoplastic cells
Ear: Dentigerous cyst (Temporal odontomata)
Congenital lesion (not necessarily
heritable)
• Temporal bone and pinnae associated
cyst
• Affects young horses
• Broad-based cysts that is contiguous
with epidermis by fistulous tract
• Generally unilateral (bilateral is extremely
rare)
• Teeth may be present in surrounding
soft tissue or underlying temporal bone
Aural hematoma
Seen in dogs with otitis externa
• Repeated vigorous head shaking
• Damages blood vessels going through
cartilage
• Hemorrhage in inner pinna
• Most common in dogs and lop-eared
pigs
• Firm, warm swelling on concave
surface of pinna
• Hangs abnormally due to increased
weight
