Patho Exam 2: Mitchell Foster

What is the outer ear supplied by

CN V (trigeminal)

What constitutes the outer ear

Auricle, external auditory canal, TM, preauricular skin, TMJ

What is the middle ear supplied by

CN IX (glossopharyngeal) and X (Vagus)

What constitutes the middle ear

Middle ear mucosa, medial surface TM, tongue, and

eustachian tube

What is the inner ear supplied by?

CN VIII (vestibulocochlear)

What is the inner ear used for

Balance and hearing

What is primary otalgia

the ear is the source of pain, abnormal ear exam

What is secondary otalgia

referred pain beyond the ear, normal ear exam

What is TMJ dysfunction

jaw clicking, tinnitus, vertigo, ear pain, jaw clenching,

neck pain, HA, trismus

What causes retracted TM

negative pressure in inner ear -> eustachian tube cannot

open and normalize pressure -> TM retracts

What is conductive hearing loss

caused by obstruction or dysfunction in

external inner ear to decrease air sound conduction

What are sources of referred otalgia that effect CN V and what is the nerve called

Tooth pain, TMJ; trigeminal

What are the sources of otalgia effecting cranial nerve VII, what is the nerve called

Facial pain; Facial

What are the sources of otalgia effecting cranial nerve IX, what is the nerve called

Posterior pharynx, tonsil, back of tongue pain; glossopharyngeal

What are the sources of otalgia effecting cranial nerve X, what is the nerve called

Laryngitis, esophageal, stomach pain; vagus

What are the sources of otalgia effecting Spinal nerves, what is the nerve called

Neck or occipital pain; cervical

Why is pain perceived in the ear due to TMJ

The vagus nerve (CN X) collects sensory information from the TMJ and the front of the EAC. So, due to proximity, any inflammation to the TMJ can be referred to the ear

What are associated S/Sx pointing to TMJ

jaw/facial pain, HA, jaw stiffness,

clicking, popping grinding, trismus, ear pain, tinnitus.

Explain how the Eustachian Tube normally functions

equalize pressure across TM

· protect middle ear from nasopharyngeal fluid

· clear middle ear secretions

· opens during swallowing, chewing, yawning via palatini

muscles

What is Eustachian Tube Dysfunction due to allergies

tube is swollen or filled with secretions

thus unable to equalize pressure -> bulging TM

What is Eustachian Tube Dysfunction due to shape

children have horizontal, short, floppy ET that are open

most of the time

What is Eustachian Tube Dysfunction due to smoking

damage cilia so secretions can't be moved out causing buildup and plugging

What is Eustachian Tube Dysfunction due to thick mucus

Secretions become stuck and have a hard time moving out leading to inability to equalize pressure

What is a cholesteatoma

cause masses composed to keratinized squamous epithelium and accumulated keratin debris

What is the patho of cholesteatomas

· ET dysfunction causes persistent neg pressure in the middle of

the ear, pulling TM inward

· Forms a retraction pocket (usually at pars flaccida)

· Keratinized squamous epithelium lines the pocket

· Desquamated epithelia accumulate in the pocket

· sac forms and creates cholesteatoma

Why is there hearing loss associated with a cholesteatoma

erosion of ossicles and physical obstruction of sound

transmission

What are some outcomes to untreated cholesteatomas

· Could eventually reach the otic capsule and cause

sensorineural (permanent) hearing loss

· Can also cause dizziness/vertigo d/t creating abnormal

openings in the inner ear

What are the pathogens for mastoiditis

streptococcus pneumoniae/pyogenes, staph aureus

What is the mechanisms causing mastoiditis

AOM inflammation -> purulent material in mastoid air cells -> pressure increases -> thin bone (septae) between air cells destroyed -> abscess cavities -> pus continues to destroy surrounding bone

What are the complications to mastoiditis

· Bone: advanced osteomyelitis

· Inner ear: hearing loss or labrynthitis

· Nervous: CN VII (facial) -> facial paralysis

o Brain -> meningitis

· MSK: neck/head bezold abscess (postauricular abscess)

Mechanisms for conductive hearing loss

dysfunction or blockage in EAC or middle ear. Sound unable to be conducted through the air. Often reversible.

Causes for conductive hearing loss

cerumen impaction, foreign body, cholesteatoma, ET dysfunction

Mechanism for sensorineural hearing loss

damage directly to cochlea or CN VIII

(vestibulocochlear). Permanent.

Causes of sensorineural hearing loss

age, Meniere's disease, noise exposure, diabetes, hereditary malfunctions, trauma

How does an air-bone gap contribute to conductive hearing loss

diminished air conduction,

preserved bone conduction

How does an air-bone gap contribute to sensorineural hearing loss

diminished air AND bone conduction

What is the anatomy of the semicircular canals?

arranged at right angles in XYZ planes

· Anterior(Y): senses vertical head movement (nodding)

· Posterior(X): senses tilting ear toward shoulder

· Lateral(Z): senses head rotation (shaking head no)

What is the anatomy of the ampullae

enlarged portion of semicircular canals right before the

cochlea.

What is the endolymph

fluid which fills semicircular canals, utricle, saccule. Contained within the ampullae

What is the anatomy of the crista ampullaris

Contains balance receptors (hair cells), cupula, sensory nerve fibers

What is the cupula?

gelatinous material above hair cells

(same density as endolymph) which responds to

endolymph flow

What are the utricles

detects horizontal movement and head tilting

What is the saccule

detects vertical body movement (elevator, jumping)

What is the maculae

present in utricle and saccule, covered by dense membrane heavier than endolymph

What is the function of the endolymph

Senses head rotation in a few ways:

· endolymph pushes on the cupula inside the ampullae

· hair cells bend and polarize to release NTs to CN VIII

· info from CV VIII -> brain signals let you know you are

rotating

What is the otoliths made of

made of calcium carbonate crystals

What are otoliths function

Overlie vestibular hair cells in utricle and sacculae

Gravity causes movement of otoliths over hair cells to detect horizontal movement (driving in a car) in the utricle or vertical movement (elevator) in the saccule

What is vertigo

sensation of self-motion when there is no motion or the distorted sense

of self motion during movement d/t conflicting visual, proprioceptive, and vestibular information

What is central vertigo

persistent involvement of brain structures including the brain stem, cerebellum, thalamus

What is peripheral vertigo

acute involvement of the inner ear and CN VIII

What is BPPV?

common cause of recurrent peripheral vertigo resulting from a dislodged otolith that leads to disturbances in the semicircular canals (95% posterior, 5% horizontal)

What is labrynthitis?

hearing is affected d/t cochlear branch of CNVIII involvement

What is the patho of vestibular neuronitis/neuritis

Inflammation of the vestibular portion of the vestibulocochlear nerve

(CN VIII). Often occurs after a URI causes an inner ear infection

Is hearing affected in vestuibular neuronitits/neuritis? How is it percieved?

Unilateral vestibular neuronitis makes the brain interpret movement

from the unaffected side only. Hearing is unaffected.

What is the basic patho for benign paroxysmal positional vertigo

otoliths become dislodged from the utricle or saccule

enter semicircular canals

disrupt endolymph flow

stimulate ampullary hair cells (interpreted as movement)

Hearing is unaffected

Otoliths can be moved back to utricle using the Epley maneuver

What is the pathology for Meniere's disease?

underlying cause unclear

excess endolymph accumulation in inner ear

· increases pressure causing damage to cochlea and vestibular

apparatus

causes vertigo, sensorineural hearing loss, tinnitus

What is the patho for motion sickness

Sensory mismatch of visual, vestibular, proprioceptive signals about

body movement and position

· Ex: Reading in a moving car

o Eyes focused on stationary book

o Inner ears sense horizontal movement

Signals pass through the vestibular nuclei in the brainstem. Causes n/v, sweating, increased saliva