PBL 14.2

Question 1

What are the components & functions of:

• External ear
• • Middle ear*
• • Internal ear*

Answer 1

Question 2

What is the vasculature of the external ear?

Answer 2

Vasculature:

• Supplied by branches of external carotid artery:
  
  • Posterior auricular artery
  • Superficial temporal artery
  • Occipital artery
  • Maxillary artery (deep auricular branch) – supplies the deep aspect of the external acoustic meatus and TM only

Question 3

What is the innervation of the external ear?

Answer 3

Innervation:

• Great auricular nerve
• Lesser occipital nerve
• Auriculotemporal nerve
• Branches of facial and vagus nerve

Question 4

Label the diagram of the external ear

Answer 4

Question 5

Label the diagram of the tympanic membrame

Answer 5

Question 6

Label the diagram of ossicles in ear

Answer 6

Question 7

Label the diagram of the internal ear

Answer 7

Question 8

What is the innervation to the inner ear?

Answer 8

• Vestibulocochlear nerve (VIII) – enters the inner ear via internal acoustic meatus where it divides into vestibular nerve (balance) and cochlear nerve (hearing)
• Facial nerve also passes through the inner ear but doesn’t innervate any of the structures present

Question 9

What is the function of the vestibulocochlear nerve?

Answer 9

• Transmits SENSORY information about SOUND & BALANCE from the inner ear to the brain

Question 10

How can you test someone’s vestibulocochlear nerve?

Answer 10

1. Hearing
   
   • Whisper and cover opposite ear (say number)
2. Rinne’s test
   
   • Tunic fork on mastoid process (BC then AC which one louder?)
     
     • Rinne’s +ve = AC>BC
     • Rinne’s -ve = BC>AC (conductive hearing loss/dead ear)
3. Weber’s test
   
   • Tunic fork on forehead
     
     • Ask sound the same both sides
       
       • If NOT:
         
         • _​_Conductive = sound better in BAD ear
         • Sensorineural = sound better in GOOD ear
4. BALANCE
   
   • ​​Ask march on a spot and close eyes

Question 11

What is the function of the facial nerve?

Answer 11

• Transmits MOTOR information from brain to the muscles of facial expression & stapedius muscle (involved in regulating hearing)
• Also, SENSORY in taste of anterior 2/3 of tongue

Question 12

How can you test someone’s facial nerve?

Answer 12

1. Test muscles facial expression​
   
   • Inspect face for symmetry and or for involuntary movements
   • Ask to raise eyebrows
   • Test power by saying “close your eyes tight and don’t let me open them and puff out your cheeks and don’t let me push them in”
   • Purse your lips, bare your teeth
2. Test hearing
   
   1. ​“Hearing sounds LOUDER than usual?”
3. Test taste
   
   1. ​“Any change in taste?”

Question 13

Explain the basic anatomy of the throat

Answer 13

Has 3 sections:

1. Oropharynx (superior)
2. Hypopharynx
3. Larynx (inferior)
   
   • Vestibular fold
     
     • ​Are fixed folds –> protection to larynx
   • Vocal folds
     
     • ​Abducted/adducted and control pitch of sound created

Question 14

Explain the basic histology of the throat

Answer 14

• Non-keratinised stratified squamous epithelium- provides protection against foreign bodies which may accidentally enter the larynx

Question 15

Explain phonation/mechanism of speech production

Answer 15

1. Respiration
   
   • Energy behind speech
   • Speech- inhale:exhale ratio = 10:90
   • Normally exhales are passive- become active in speech and singing (use of abdominal muscles and diaphragm)
2. Phonation (voicing)
   
   • Vocal cords (vocal folds)
   • Pushed together -> air from lungs forces them open and causes them to vibrate
3. Resonance
   
   • Once sound is created, it flows up through cavities
   • 3 options: throat, mouth and nose (nasal)
   • Can manipulate these spaces to change how voice sounds
4. Articulation
   
   • How you shape the sound with your mouth to create words
   • Tongue is main articulator (also; lips, teeth, cheeks, palate)

Question 16

How do we say specific letters out loud?

Answer 16

• Tongue- major articulator in phonation, ‘t’ and ‘g’
• Teeth- provide important place of articulation for tongue and lips
• Lips- purpose is to open and close accordingly to create speech, ‘p*’, ‘*b*’ and ‘*m’
• Vocal cords (vocal folds)- vibrate together in various ways to determine pitch of sound, based on vibration a sound may be voiced or voiceless (eg. ‘h’ is voiceless)

Question 17

What are the stages in speech production?

Answer 17

1. Conceptualisation
   
   • ​Think spontaneously what going to say
2. Formulation
   
   • ​Formulating words together
3. Articulation
   
   • ​Person says what wanted to say
4. Self-monitoring
   
   • ​Speaker reflects on what they have said (e.g. for correction)

Question 18

What is the vestibular system & explain it

Answer 18

• Vestibular system = uses information about head movement to maintain balance and coordination
• ​Contains vestibular labyrinths
  
  • ​Made of semi-circular canals & otolith organs
    
    • Semi-circular canals = three fluid filled tubes (at right angles to each other) in the inner ear that are capable of detecting different rotational accelerations of the head (has endolymph)
      • EL into ampula (contain crista ampularis - which have hair cells)
      • Hair cells have stereocilia at the top of the cells
        
        • Are in height order –> towards tallest = ion channels open causing depolarisation (so AP down vestibulocochlear nerve –> tells brain about movement)
    • Otolith organs = collective term used to describe the utricle and the saccule
    • Utricle = detects linear accelerations of the head and head tilts in the horizontal plane.
    • Saccule = detects linear accelerations of the head and head tiles in the vertical plane.
• Contain receptors send info via vestibulocochlear nerve

Question 19

Explain the hair cells in the otolith organs

Answer 19

• The hair cells are in the macula
• Above the macula is a gelatinous layer and then a otolithic membrane.
• The otolithic membrane has small calcium carbonate crystals called otoconia.
• These crystals make the membrane heavier.
• When the head moves in either the horizontal or vertical plane the otoconia move in that direction.
• This causes the hair cells to be displaced.
• This opens the channels and leads to the release of NT.
• The vestibular system uses the information about the movement to maintain balance, stability and posture.

Question 20

How do hair cells work?

Answer 20

1. The hair cells are in contact with both the tectorial and basilar membrane.
2. When the basilar membrane is vibrated due to the stapes and the disruption in fluid within the cochlea and cochlear duct, the hair cell stereocilia bend to slide over the tectorial membrane.
3. As they are arranged in height when they bend towards the largest stereocilia the smallest side is stretched and ion channels are opened. This generates depolarisation of the hair cell membrane and and impulse is generated.
4. When they bend the towards the smaller stereocilia the ion channels close.
5. When they’re straight there is just a low level of depolarisation.

Question 21

What are the 2 types of hearing?

Answer 21

1. Conductive
2. Sensorineural

Question 22

What is an otitis media infection?

Answer 22

• Otitis media infection of the middle ear what is originated from the upper respiratory tract and travel through the Eustachian tube
  
  • Similar pathogen is on the upper respire tree tract e.g. streptococcus pneumoniae and haemophilus influenzae (usually viral in origin)
• Commonly affects children under the age of 10
• Causes inflammation of the middle ear mucosa and inflammatory exudate in the middle ear space
• Symptoms include otalgia (pain in ear) and hearing disturbances
• Usually presents with otalgia first followed by discharge
• Initial treatment for an acute case is non-steroidal anti-inflammatory drugs
• If symptoms occur for more than 72 hours should prescribe an antibiotic such as amoxicillin
• Swelling and tenderness over the mastoid should have an urgent ENT appointment

Question 23

What is meant by thinning of the tegmen & how can you diagnose this?

Answer 23

• Dehiscence of tegmen tympani/mastoidium and can be secondary to prior surgery or a chronic otitis media
• Diagnosis is made by axial/coronal CT (as was done in this case) of the temporal bones
• Separates the middle ear from the middle cranial fossa (where brain is)
  
  • If goes through = meningitis & intracranial abscesses

Question 24

What is cholesteatoma? (&explain it)

Answer 24

• Cholesteatoma - progressive destructive ear disease (skin builds up in layers – like an onion & erodes bone of the middle ear & mastoid)
• Outer layer = matrix contains growing skin cells (acts like cancer –BUT is NOT cancer)
• Usually, slow progression
• Early stages = cholesteatoma attacks the ossicles (causes partial deafness, unpleasant smelling discharge & painful)
• Long term – erode inner ear & cause total and permanent deafness & tinnitus (experience ringing/other noises in one or both ears)
• If cholesteatoma erodes balance organ (vestibular system) then vertigo will occur (severe dizziness – feeling of going in circles & constantly moving)
• Can also attack facial nerve (CN VII) leading to facial paralysis

Question 25

What are grommets?

Answer 25

• Grommets – very small plastic tubes (sit in a hole in the eardrum), letting air go in & out of the ear, enables the ear to be healthy
• Placed in the ear drum under short general anesthetic, operation down ear canal so NO incisions, small opening in tympanic membrane using a microscope and then fluid is sucked out using a fine sucker, grommet then placed in ear drum (~10-20min operation)
• Grommets fall out on their own as the tympanic membrane grows (can stay in for 6 months-1year)
• May not notice when they drop out (usually grommets aren’t painful)

Question 26

What is acute coalescent mastoiditis?

Answer 26

• From otitis media spread to the mastoid air cells and then this can cause bony septation erosion and coalescence of small air cells which can then become very large and full of pus

Question 27

What is meant by an extradural abscess drained via the mastoid?

Answer 27

Removal of pus etc. from the extradural space via going through the mastoid bone (process) in order to remove this

Question 28

What is a mastoid tympanoplasty (& explain it)?

Answer 28

• Surgery performed to correct middle ear problems in the tympanic membrane and the ossicles when medical treatment is not effective
• Commonly performed to prevent chronic ear infections from spreading to the mastoid bone and causing damage
• Remove infected portion of the mastoid bone (usually) and then reconstruct tympanic membrane (done under general anesthetic)
• Can be done through ear canal if not incision is done behind the ear
• Using a drain in situ (on the site affected) as during surgery when serous fluid & blood mix together (known as serosanguineous fluid) the drain will collect this fluid to lower the risk of infection and seroma (build up of fluid in the soft tissue)

Question 29

What is pure-tone audiometry?

Answer 29

• Made of 2 parts:
  
  1. Air conduction tests the outer and middle ear
  2. Bone conduction tests the inner ears hearing capabilities

Question 30

How would normal hearing be seen on an audiogram?

Answer 30

• Normal hearing levels are 20 dB (0-20) or better across all frequencies

Question 31

What are the degrees of hearing loss?

Answer 31

Question 32

How would conductive hearing loss be seen on an audiogram?

Answer 32

Question 33

How would sensorineural loss be seen on an audiogram?

Answer 33

Question 34

How would mixed hearing loss be seen on an audiogram?

Answer 34

Question 35

What is:

1) Sensorineural hearing loss
2) Conductive hearing loss

& what are the causes of them?

Answer 35

1. Sensorineural hearing loss
   
   • Usually due to loss of cochlear hair cells via damage to CN VIII (vestibulocochlear nerve) or lesions/ damage to the central auditory pathway.
2. Conductive hearing loss
   
   • Impaired sound transmission in ext. or middle ear impacting all sound wave frequencies.
   • Causes:
     
     • Ear wax plugging ext. Auditory canal.
     • Otitis externa* (swimmers’ ear) or *Otitis media -> inflammation of external or middle ear causing fluid accumulation.
     • Burst or perforated tympanic membrane (eardrum)
     • Osteosclerosis as bone is reabsorbed and replaced over oval window.

Question 36

Amoxicillin

Answer 36

Pharmacology:

• Competitive antagonist
• Primary target= Penicillin binding protein 1

Physiology:

1. Inhibits penicillin binding protein 1
2. This is responsible for the reactions that lead to the cross linking of D-alanine and D-aspartic acid in the bacterial cell wall
3. When this is inhibited it causes the bacteria to upregulate autolytic enzymes as a response to the cell wall damage
4. Bacteria is unable to repair and build the cell wall
5. Leads to death of bacterium

Clinical:

• Amoxicillin is used to treat susceptible bacterial infections of the ear, nose, throat, GI tract, skin and lower respiratory tract

Question 37

What is the importance of completing a course of antibiotics?

Answer 37

• Highly important to complete course of antibiotics even if you are no longer experiencing any symptoms
  
  • This is because the infection may not be fully cleared, which may cause a subsequent infection to develop
• If you don’t finish the course some bacterium may have a degree of resistance to the treatment which could mean that the infection isn’t cleared. Stopping the course will allow these bacteria to grow

Question 38

What are the milestones of a 7 year old?

Answer 38

• Understanding + listening:
  
  • Be able to listen to a book
  • Show interest and engagement in lessons
  • Follow complex instructions independently
  • Be interesting and concentrate when an adult explains rules or gives information
• Speaking:
  
  • Should be able to communicate independently. Know around 3000 words
  • Speak without obvious sound errors
  • Use language with few grammatical areas
  • Be able to provide detailed answers when asked questions: E.g “ What have you done today”?
  • Tell event based news to others and peers
• Social:
  
  • Communicate and interact with peers
  • Follow, enjoy and maintain conversation with others
  • Use words to explain emotions instead of physical actions
• Motor:
  
  • Ride a bike
  • Growth of 2-2.5 inches per year
  • Perform movements such as twisting, turning and spinning
  • Improved ability to perform simple chores
  • Improved coordination and balance
• Causes for concern:
  
  • Use of short sentences, regular grammatical errors
  • Articulation errors in speech
  • Difficulty expressing themselves
  • Unable to listen to a story
  • Difficulties following instructions and engaging in conversations

Question 39

What is the impact of having an unaddressed hearing loss? (especially in children)

Answer 39

1. Communication & speech affected
2. Cognition
3. Education & employment
   
   • ​​Higher unemployment rates & developing countries DO NOT recieve schooling
4. Social isolation, loneliness & stigma

Question 40

How to communicate with someone with a hearing impairment?

Answer 40

• Turn your face towards the person and ensure your face is well-lit so your lip movements can be easily seen.
• Don’t shout or over-exaggerate words or lip movements. This can actually make it harder for the person to understand you.
• Speak clearly and slightly slower, but keep the natural rhythms of your speech.
• Don’t cover your mouth.
• Consider using visual prompts such as objects or pictures to help