Ears, eyes Flashcards
Which CN provide innervation to the muscles of the middle ear?
– Trigeminal nerve, cranial nerve 5
– Facial nerve, cranial nerve 7
What structure communicate the middle ear with the pharynx?
auditory tube
What is the hypothesized fxn of the guttoral pouch in horses?
diverticulum of the auditory tube that serves as an extracalvarial cooling system d/t the ICA running though the pouch and it can inflate.
What bone makes up the internal ear?
petrous portion of the temporal bone
Describe the anatomy of the middle and internal ear.
External ear pathology?
auricular hypoplasia
normal breed variation
External ear pathology?
auricular hypoplasia
spontaneous
likely hearing loss
External ear pathology
auricular infarction
frostbite
most common neoplasm in the external acoustic meatus? In cats or dogs is it more likely to be malignant?
sebaceous tumors
cats 85%; dogs 60%
What neoplasms are common on the pinna of the ear in dogs vs. cats?
Type of ear neoplasm
aural SCC
External ear pathology?
How is it transferred?
Is the owner does not like the site of this, will it go away on its own?
equine ear papillomas aka aural plaques
>1yr
transferred by fly bites
no
A 4 yr old cat presents with Auricles – bilaterally swollen, erythematous, painful, pruritic, curled. Likely DDX?
What age do we see this?
auricular chrondritis (immune mediated response that targets the cartilage)
>3yrs
A cat presents with a blue/black grape like appearance in the ear. Likely DDX?
The owner wants to know if it is malignant?
feline ceruminous cystomatosis (cystic proliferation of ceruminous glands)
benign
What is this?
Is it more likely a cat or dog?
What are the age ranges for this to develop?
ceruminous gland carcinoma in the ext. acoustic meatus
CAT
Cat: DSH 7-13yrs
dogs: 5-12yrs
Which breeds of dogs are more likely to get ceruminous gland carcinoma?
English bull terrier, Belgian malinois, shih tzu
Where is a ceruminous gland carcinoma most likely to metastasize to first? Is it likely to go other places?
What is the treatment?
parotid l.n.
no
TECA
A <2 yr old cat presents with the following. The owner is concerned its cancer. What do you tell her?
What are two locations the polyp can go?
aural inflammatory polyp
non-neoplastic
nasophaynx; protrude through tympanic membrane
Are aural polyps an external, middle, or inner ear condition?
middle ear
What are the two common types of infections in the equine guttoral pouch? Which is associated with more complications?
■ Bacterial
– Streptococcus equi -Strangles
■ Fungal - guttural pouch mycosis
– Aspergillus sp.
■ Guttural pouch mycosis tends to cause more complications
A horse presents with epistaxis, dysphagia, Horner’s syndrome, facial paralysis. On endoscopy, the picture was obtained. DDX?
What important structures are affected that can account for the clinical signs?
guttoral pouch mycosis
Important structures:
– Internal and external carotid arteries
– CN VII, IX, X, XI, XII
– Cranial sympathetic trunk
What congenital condition is likely in this animal? Why?
deafness- cochleosaccular degeneration
Pigmented neural crest-derived intermediate cells are important for hearing
– If lack pigment -cochloesaccular degeneration -can result in deafness
Dogs breeds associated with hereditory deafness
Australian cattle dogs, Australian sheepdogs, border collies, bull terriers, Norwegian Dunkers, West Highland white terriers, Great
Danes , Great Pyrenees, Lousiana Catahoula Cattle dogs, Old English Sheepdogs, Maltese, and Dachshunds
Anatomy of the eye
What is the * indicating?
dainage angle
Name the layers of the retina.
Retinal dysplasia (abnormal development) can occur in utero or post-natal for ungulates? Carnivores?
Ungulates: in utero (retina fully developed at birth)
Carnivores: in utero/post-natal (retina develops 6wks after birth)
Common in which species after ingestion of what toxin on day …. of gestation?
Synopthalmia
sheep; veratrum californicum; Day 15
How common is glaucoma in dogs vs. cats vs. horses?
dogs >> cats >horses
stretching of eye due to increased intraocular
pressures
buphthalmos
What is the difference between primary and secondary glaucoma?
Primary: no acquired introcular dz (developmental lesion of the drainage angle)
Secondary: intraocular disease
What is the ocular condition? What are secondary causes for this condition and what is the commonality between all of them?
Glaucoma
- fibrovascular proliferation (w/ tumor/uveitis)
- lens luxation
- inflammation (fill up with pus/granulation tissue)
- introcular neoplasia
ALL BLOCK THE DAINAGE ANGLE
A dog presents with ocular pain and blindness, buphthalmos, corneal edema, collapse of iridocorneal angle. DDX?
glaucoma
What are the histologic lesions seen with glaucoma?
Which feature is observed in the picture?
■ Retinal atrophy
■ Collapse of iridocorneal angle
■ Optic nerve head cupping
■ Scleral thinning
What type of glaucoma is depicted?
What two structures connect that closes the drainage angle?
Primary Glaucoma- Goniodysgenesis
Mature iris stroma (short black arrow) connects to Descemet’s membrane resulting in closure of the drainage angle
What is the structure called and composed of?
What two structures in the eye can it develop on?
Dermoid
Composed of ectopic hair follicles and adnexal glands
cornea or conjunctiva
What type of damage results in this?
Where can is be located?
SCC
actinic damage (solar keratosis)
globe or eyelid (often light/non-pigmented skin)
Name?
Most Commonly occurs in which Species?
When does it occur?
Corneal sequestrum ( development of an opaque, dark brown to black plaque on the cornea which is a dead piece of corneal tissue)
Cats
chronic corneal ulceration
Which breed of dog is presiposed to lens luxation d/t defects in collagen?
Border collies
Condition?
What type of changes are associated with this condition?
lens luxation
cataract changes
What are the top two ocular neoplasms in cats?
- melanoma
- Feline post-traumatic ocular sarcoma
A cat presents with the following neoplasm (*). What is the likely DDX?
What does the tumor arise from?
The owner wants to know its potential to metastasize?
Feline post-traumtic ocular sarcoma
lens epithelium
highly invasive, can met
A DOG presents with exophthalmus, vision loss, optic n. degeneration and atrophy. DDX?
meningioma
