Ch. 44 - Ear Disorders

Pathophysiology Exam 3

What is the function of the tympanic membrane?

The tympanic membrane (eardrum) vibrates when sound waves strike it and transfers those vibrations to the ossicles in the middle ear

What are the three ossicles of the middle ear?

Malleus (hammer)

Incus (anvil)

Stapes (stirrup)

What is the function of the ossicles?

They amplify and transmit sound vibrations from the tympanic membrane to the oval window of the inner ear

What is the cochlea?

The cochlea is a spiral-shaped structure in the inner ear that converts sound vibrations into electrical nerve impulses through hair cells in the organ of Corti

What cranial nerve carries hearing information from the cochlea to the brain?

The vestibulocochlear nerve (Cranial Nerve VIII)

What is the function of the Eustachian tube?

It equalizes air pressure between the middle ear and the atmosphere and drains fluid from the middle ear into the nasopharynx

Why are children more prone to otitis media?

Their Eustachian tubes are shorter, narrower, and more horizontal, allowing bacteria and viruses to reach the middle ear more easily

Which part of the ear is responsible for hearing?

The cochlea in the inner ear

Which part of the ear is primarily responsible for balance?

The vestibular apparatus (semicircular canals, utricle, and saccule) in the inner ear

Describe the pathway of sound through the ear?

Sound waver travel through the external auditory canal → Tympanic membrane → Ossicles (malleus, incus, stapes) → Oval window → Cochlea → Cranial Nerve VIII → Brain

What is conductive hearing loss?

Hearing loss caused by problems in the outer or middle ear that prevent sound from reaching the inner ear

What are common causes of conductive hearing loss?

Cerumen impaction

Otitis media

Tympanic membrane perforation

Foreign bodies

Otosclerosis

What is sensorineural hearing loss?

Hearing loss caused by damage to the inner ear (cochlea), hair cells, or Cranial Nerve VIII

What are common causes of sensorineural hearing loss?

Aging (presbycusis)

Prolonged loud noise exposure

Ototoxic medications
Infections

Tumors

Meniere disease

Which type of hearing loss is usually permanent?

Sensorineural hearing loss

Which type of hearing loss is often reversible or treatable?

Conductive hearing loss

Which hearing loss affects the transmission of sound to the inner ear?

Conductive hearing loss

Which hearing loss results from damage to the auditory nerve or cochlear hair cells?

Sensorineural hearing loss

Which type of hearing loss may improve with hearing aids or cochlear implants?

Sensorineural hearing loss (depending on severity)

What is the key difference between conductive and sensorineural hearing loss

Conductive hearing loss is due to problems in the outer or middle ear, while sensorineural hearing loss is due to damage in the inner ear or auditory nerve

What is myringotomy?

A myringotomy is a surgical procedure in which a small incision is made in the tympanic membrane (eardrum) to drain fluid from the middle ear

What is the purpose of placing myringotomy (tympanostomy) tubes?

Ventilate the middle ear

Equalize pressure

Prevent fluid buildup

Reduce recurrent ear infections

When are myringotomy tubes commonly indicated?

For recurrent acute otitis media or persistent middle ear effusion that causes hearing loss or affects speech and language development

How are myringotomy tubes placed??

A small incision is made in the tympanic membrane, fluid is suctioned from the middle ear, and a tiny tube is inserted into the opening to keep it open

How long do myringotomy tubes usually remain in place?

They typically remain in place for 6-18m months before falling out on their own as the eardrum heals

What is tinnitus?

The perception of ringing, buzzing, hissing, or other sounds in the ears without an external sound source

What are common causes or tinnitus?

Hearing loss

Prolonged loud noise exposure

Earwax buildup

Ototoxic medications

Meniere disease

Aging

What is labyrinthitis?

Inflammation of the inner ear (labyrinth), usually caused by a viral infection, affecting both hearing and balance

What are the signs and symptoms of labyrinthitis?

Sudden vertigo

Dizziness

Nausea

Vomiting

Hearing loss

Tinnitus

Difficulty with balance

What is the key difference between tinnitus and labyrinthitis?

Tinnitus is a symptom involving ringing or buzzing in the ears, while labyrinthitis is an inflammatory disorder of the inner eat that causes vertigo, balance problems, and often hearing loss

What is otitis media?

An infection or inflammation of the middle ear, usually occurring after an upper respiratory infection

What is the pathophysiology of otitis media?

Eustachian tube dysfunction leads to fluid accumulation in the middle ear, creating an environment where bacteria or viruses can grow

Why does Eustachian tube dysfunction contribute to otitis media?

It prevents proper drainage and pressure equalization, allowing fluid to become trapped behind the tympanic membrane

What organisms commonly cause acute otitis media?

Streptococcus pneumoniae

Haemophilus influenzae

Mortadella catarrali

What are the common signs and symptoms of otitis media?

Ear pain (otalgia)

Fever

Decreased hearing

Irritability (especially in children)

A feeling of fullness in the ear

What are the typical findings on otoscopic examination in otitis media?

A bulging, erythematous (red), and immobile tympanic membrane, often middle ear effusion

How is otitis media diagnosed?

By history and physical examination using otoscope, which reveals characteristic changes in the tympanic membrane

How is otitis media treated?

Mild cases may be observed

Bacterial infections are commonly treated with amoxicillin, along with pain management using acetaminophen or ibuprofen

What complications can occur if otitis media is untreated?

Hearing loss

Tympanic membrane rupture

Mastoiditis

Chronic infections

Delayed speech development in children

Why are children at greater risk for recurrent otitis media?

Their Eustachian tubes are shorter, narrower, and more horizontal, making drainage less effective and infection more likely

Which part of the ear converts sound vibrations into electrical nerve impulses?

The cochlea

Which part of the er equalizes pressure between the middle ear and the atmosphere?

The Eustachian tube

Which type of hearing loss is caused by damage to the cochlea or Cranial Nerve VIII?

Sensorineural hearing loss

Which type of hearing loss is caused by problems in the outer or middle ear?

Conductive hearing loss

What is the primary purpose of myringotomy tubes?

Ventilate the middle ear

Drain fluid

Reduce recurrent infections

Improve hearing