Ear disorders and testing ear function Flashcards by James Zechella

What causes Ramsay Hunt syndrome?

Reactivation of VZV

in the geniculate ganglion of the CN7 facial nerve

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What happens to the ear in Ramsay Hunt syndrome?

Vesicular rash on upper pinna

and external auditory meatus

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Why is there a vesicular rash on the upper pinna and external auditory meatus in Ramsay Hunt syndrome?

Due to the facial nerve carrying sensory information from this part of the ear

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What is a pinna haematoma?

Bleeding between the cartilage and perichondrium of the pinna

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What causes a pinna haematoma?

Trauma

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What are the complications of a pinna haematoma?

Necrosis of the cartilage in the pinna

Cauliflower deformity

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What causes necrosis of cartilage in the pinna in a pinna haematoma?

Cartilage is avascular, perichondrium carries it blood supply
if blood accumulates between the two, separates the two
cartilage suffers avascular necrosis

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What causes a cauliflower deformity of the pinna?

After necrosis of cartilage in pinna
fibrosis occurs
new asymmetrical cartilage may form
both as part of healing

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How is a pinna haematoma treated?

Drain the blood from the pinna

re-align the cartilage and the perichondrium to give it back its blood supply

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How can wax in the external auditory meatus affect ear function?

If it builds up and blocks the external auditory meatus
prevents sound vibrations reaching tympanic membrane
loss of hearing

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What is otitis externa?

Inflammation of the external auditory meatus

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What are the signs and symptoms of otitis externa?

External auditory meatus is
red
swollen
painful
contains exudate, discharge

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What are the causes of otitis externa?

Infection

Allergy

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What can predispose to otitis externa?

Swimming

Skin problems e.g. dermatitis (eczema)

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What can cause perforation of the tympanic membrane?

External pressure

Inernal pressure due to infection of middle ear
increased pressure in middle ear
pushes against tympanic membrane

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How is a perforated tympanic membrane treated?

It resolves itself

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What can cause bulging of the tympanic membrane?

Infection of middle ear

increased pressure in middle ear

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What is otosclerosis?

Ossicles fuse with each other where they normally articulate with each other

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Which ossicle is most commonly affected by otosclerosis?

Stapes

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What does stapes fuse with in otosclerosis?

Its base plate fuses with the oval window

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How does otosclerosis of stapes with the oval window affect ear function?

Reduced vibration of stapes against oval window

loss of hearing

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What is hyper-acusis?

Sensitivity to loud noises

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What is one of the causes of hyper-acusis?

Problems with nerve to stapedius of facial nerve
reduced function of stapedius muscle
doesn’t control vibrations of stapes base plate against oval window when loud sounds are heard

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What causes otitis media with effusion?

Reduced function of eustachian tube
increased negative pressure in middle ear cavity
draws transudate fluid out of mucosa lining middle ear cavity

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What does otitis media with effusion predipose to?

Acute otitis media

How does otitis media with effusion affect ear function?

Reduced vibrations of tympanic membrane, ossicles | loss of hearing

How does otitis media with effusion affect the tympanic membrane?

Is retracted | because the negative pressure in the middle ear cavity draws it inwards

How is otitis media with effusion treated?

May resolve itself in a few months Or use grommets

How do grommets treat otitis media with effusion?

Drain away fluid Ventilate middle ear cavity to equilibriate pressure in it with atmospheric pressure

What causes acute otitis media?

Infection of the middle ear

What age group is acute otitis media more common in?

Children

Why is acute otitis media more common in children?

Eustachian tube is shorter and more horizontal easier for infection to travel from nasopharynx to middle ear also easier for tube to become blocked, leading to otitis media with effusion, increased risk of acute otitis media

What causes blockage of the eustachian tube in children?

Enlarged adenoids, pharyngeal tonsils

What are the signs and symptoms of acute otitis media?

Otalgia, pain of ear Tympanic membrane is red, bulging Fever

What are the complications of acute otitis media?

Tympanic membrane perforation Facial nerve damage Mastoiditis Intracranial problems

Why can acute otitis media damage the facial nerve?

Because the facial nerve passes through the internal auditory meatus, facial canal near the middle ear

Why can acute otitis media lead to mastoiditis?

Because the middle ear is within the petrous part of the temporal bone continuous with the mastoid air cells infection can spread from the middle ear into these mastoid air cells

Why can acute otitis media lead to intracranial problems?

Because the middle ear is within the petrous part of the temporal bone close to the meninges, sigmoid sinus infection can spread from middle ear into them

What are the signs of symptoms of mastoiditis?

Behind the ear, it is red swollen painful Ear is pushed forwards

What is choelasteatoma?

Abnormal skin growth in a retracted pouch of the tympanic membrane

What are the causes of a cholesteatoma?

Reduced function of Eustachian tube negative pressure in middle ear draws tympanic membrane and skin inwards Chronic ear infections

How does a cholesteatoma affect ear anatomy?

Erodes structures it comes into contact with e.g. ossicles mastoid process

What are the signs and symptoms of cholesteatoma?

Painless otorrhea Hearing loss

Why does cholesteatoma give painless ear discharge?

Cholesteatoma predisposes to infection of middle ear

Why does cholesteatoma give hearing loss?

Prevents vibrations in external auditory meatus reaching tympanic membrane Reduces vibrations of tympanic membrane

What is otorrhea?

Ear discharge

What causes Meniere's disease?

Increased fluid in inner ear affects the stereocilia on the hair cells in the spiral organ of Corti and sterocilia on hair cells in vestibular apparatus

What are the symptoms of Menier's disease?

Vertigo Tinnitus Hearing loss

What is vertigo?

Sensation of room spinning

What is tinnitus?

Ringing in the ears

What causes benign paroxysmal positional vertigo?

Calcium crystals in the fluid of the vestibular apparatus

What is the main symptom of benign paroxysmal positional vertigo?

Short episodes vertigo every time the person moves their head

What is the explanation for the main symptom of benign paroxysmal positional vertigo?

Every time move head calcium crystal in semicircular duct moves due to effect of gravity this keeps moving stereocilia on hair cells even after head is still

What is meant by labyrinthitis?

Inflammation of the vestibular apparatus of the inner ear

What is meant by conductive hearing loss?

Hearing loss due to problem in external auditory meatus, tympanic membrane, ossicles

What is meant by sensorineural hearing loss?

Hearing loss due to problem in cochlea, cochlear part of CN8 vestibulocochlear nerve, primary auditory cortex

What examinations are done for a patient with hearing loss to determine what type of hearing loss it is?

Tuning fork tests

What are the types of tuning fork tests?

Rinne's test Weber's test

How is Rinne's test done?

Tuning fork ringing next to ear Tuning fork ringing with base at mastoid process

How is Weber's test done?

Tuning fork ringing with base at top of head

What is meant by air conduction?

Conduction of sound through air in external ear, middle ear to cochlea

What is meant by bone conduction?

Conduction of sound through temporal bone to cochlea

How does air conduction compare to bone conduction normally?

Air conduction is louder than bone conduction

What are the results of Weber's test with conductive hearing loss in one ear?

Sound is louder in affected ear

What are the results of Weber's test with sensorineural hearing loss in one ear?

Sound is louder in unaffected ear

What are the results of Rinne's test with conductive hearing loss in one ear?

Bone conduction is louder than air conduction

What are the results of Rinne's test with sensorineural hearing loss in one ear?

Air conduction is louder than bone conduction

What are some examples of causes of conductive hearing loss?

Wax Otitis externa Otitis media with effusion Otosclerosis

What are some examples of causes of sensorineural hearing loss?

Meniere's disease Presbyacusis

What is meant by presbyacusis?

Sensorineural hearing loss in people older than 55 years

What are the complications of mastoiditis?

Meningitis Temporal lobe abscess Sigmoid sinus thrombosis