Eyes and Ears Flashcards
Define auricular hypoplasia
It is a microtic lesion that could be breed-related or can occur spontaneously; if spontaneous, can get hearing loss
What happens with frostbite?
It’s an auricular infarction; blood shunted away from periphery, poorly perfused extremity undergoes necrosis
What kinds of tumors occur in the pinna?
- Dogs: sebaceous gland tumors (benign), histiocytomas, plasmacytomas, mast cell tumors
- Cats: trichoblastomas, hemangiosarcomas, SCC (white or lightly pigmented skin)
What kinds of tumors occur in the external acoustic meatus ?
- Ceruminous gland tumors
- Sebaceous tumors
- Other epithelial tumors
- 85% of cats - malignant
- 60% of dogs - malignant
What is this an example of?
Aural or pinna SCC in a cat
What are aural plaques and in what species to do they occur commonly?
- Aka - equine ear papillomas
- occur in horses over 1 yr
- papilloma virus spread b/t horses by fly bites
- rarely resolves spontaneously
What is auricular chondritis?
- Relapsing polychondritis
- immune mediated response targeting collage
- > 3 years (most often in cats)
- auricles - bilaterally swollen, erythematous, painful, pruritic, curled
What is feline ceruminous cystomatosis?
- cause unknown
- Benign
- Cystic proliferation of ceruminous glands
- blue to black appearance
What is ceruminous gland carcinoma?
- malignant carcinoma that occurs in the external acoustic meatus that invades the ear canal
- cats >>> dogs
- cats - DSH, 7-13 years
- dogs - 5-12 years
- English bull terriers, Belgian malinois, shih tzu
- Mets > parotid lymph node
- mets beyond reg l.n = rare
- Surgical excision > total ear canal ablation (TECA)
What are aural inflammatory polyps?
- Non-neoplastic
- cats < 2 yrs
- confined in middle ear, protrude into the nasopharynx, or protrude thru tympanic membrane
- tympanic bulla
Describe guttural pouch disease
- Of the auditory tube - Eustachian tube - Eustachitis
- Bacterial = Strep equi equi = Strangles
- Fungal = guttural pouch mycoses - Aspergillus sp.
- Guttural pouch mycosis tends to cause more damage > complications
Describe cochleosaccular degeneration
- Hereditary deafness
- certain pigmentary phenotypes of hair/eye color have been linked
- pigmented neural crest-derived intermediate cells are important for hearing
- If you lack pigment > cochleosaccular degeneration > can result in deafness
- Blue-eyed white cats, various dog breeds, presumed cause with alpacas, llamas, Paint horses
What are some developmental ocular anomalies?
- Common in domestic animals - particularly purebred dog breeds
- usually multiple anomalies > reflects stepwise and interconnected organogenesis of eyes
- species differences in organogenesis
- carnivores = retina continues to develop 6 wks postanatally
- herbivores =retina fully developed at birth
- Therefore, retinal dysplasia is an in utero event in ungulates and carnivores it could be in utero or postnatal
Describe synophthalmia
- Fused globes
- reflects failure of division into two globes
- sheep - veratum californicum (ingested on gestational d15)
Describe glaucoma
- Not a single dz but a clinical syndrome
- dogs >> cats > horses
- ocular pain and blindness
- Buphthalmos -stretching of eye due to incr IOP
- corneal edema
- collapse of iridocorneal angle
- primary vs. secondary
