Lecture 8: Aural Pathology Flashcards
What makes up the external ear
auricle (pinna) and external acoustic meatus
Identify structures in red and green
Red: auricle/pinnae
Green: external acoustic meatus
histo of external ear- what is indicated by 1
Ceruminous glands
What are the common routes of injury to external ear
- Extension from external environment
- Hematogenous
- Extension from middle ear
What are some common responses from injury to external ear
inflammation, fibrosis, neoplasia, hyperplasia
what is otitis externa
inflammation of external ear
what species is otitis externa most common in
dogs
what are some causes of otitis externa
hypersensitivity reactions, ectoparasites, FB—> secondarily infected with bacteria and yeasts
what are some sequela of otitis externa
stenosis—> progression to otitis media
patient induced aural hematoma
what are some causes of infarction to external ear
- bacterial septicemia (salmonella)
- Vasculitis
- Viruses- FIP
- Frostbite
- Toxins- ergot
What wrong in these pictures
left: frostbite
Right: infarct- bacterial septicema
what are some gross findings of aural hematomas
swollen, warm, hyperemic, heavy, heals by fibrosis, may be deformed
cat ear- what ectoparasite is likely
notoedres cati
Pig ear- what ectoparasite is likely
sarcoptes scabei
rabbit ear- what ectoparasite is likely
Psoroptes cuniculi
what is dermatophilosis
rain rot
what is cause of dermatophilosis
dermatophilus congolensis
t or f: dermatophilus congolensis is zoonotic
true
what is pathogenesis of dermatophilosis
transmitted from dam to offspring
what is the gross appearance of dermatophilosis
crusting and exudative dermatitis
sheep presents with crusting on body and this was histo- what wrong
Dermatophilosis- caused by dermatophilus congolensi
what are some most common external ear neoplasms in dogs
- Sebaceous gland tumors
- Histiocytoma
- Plasmocytomas
- MCt
what are some of the most common external ear neoplasms in cats
- Basal cell tumor
- Vascular tumor (hemagioma/hemagiosarcoma)
- SCC
what are some common external ear neoplasms in dogs and cats
And where do they originate
adenoma, adenocarcinoma
Ceruminous gland origin
cat Ear- notice the bilateral tumors and in lightly pigmented areas- what is top differential
SCC
what is auricular agenesis/aplasia
no external ear development
what species/breeds is auricular hypoplasia normal in
La Mancha goat and Scottish fold cats
what is atresia of external acoustic meatus and what is cause
narrowing of external acoustic meatus
Cause: congenital or secondary to trauma
the middle ear communicates with the pharynx via the __
eustachian tube
what are the routes of injury in the middle ear
- Migration along vascular or neural pathways
- Extension from perforation of tympanic membrane
- Nasopharyngeal ascending infections via Eustachian tube
what are some common responses to injury of middle ear
- Inflammation
- Impaired mucociliary clearance
- Formation of inflammatory polyps
- Horners syndrome
what is otitis media
inflammation of middle ear
what species most commonly get otitis media
ruminants and pigs
what causes otitis media in ruminants and pigs/ what route
nasopharyngeal ascending infection
what wrong
bilateral suppurative otitis media
what species are nasopharyngeal polyps most common in
cats <2yrs
what are some predisposing factors to nasopharyngeal polyps
chronic infections, otitis media, congenital defects
what are some clinical signs of nasopharyngeal polyps
upper respiratory discharge, sneezing, dyspnea, strider, voice change, dysphasia, head tilt
from cat- what wrong
Nasopharyngeal polyp
what cranial nerves are present in inner ear
V, VII, and VIII
all cranial nerves in inner ear are embedded in ___
petrous portion of temporal bone
what is the function of inner ear
vestibular system- critical for balance
what are some routes of injury to inner ear
- Extension from middle ear- most common
- Migration along vascular or neural pathways
what are some common responses to inner ear injuries
- Sensory cell degeneration/ death
- Inflammation with extension into surrounding bone—> osteomyelitis
what are some clinical signs of vestibular disease
head tilt, circling facial paralysis, ataxia
what are some causes of vestibular disease
congenital, idiopathic, concurrent otitis media/interna, aural or intracranial neoplasia
what is otitis interna
inflammation of inner ear
What wrong and what can it result in
otitis interna—> can result in meningitis, ventriculitis, encephalitis
what wrong and what cause
aural plaques caused by papillomavirus
what is feline Ceruminous cystomatosis
benign, idiopathic cystic dilation and non-neoplastic proliferation of Ceruminous glands
Cat ear- what wrong
Feline Ceruminous cystomatosis
