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MBBS IV - Junior Clerkship WCS > JC97 (ENT) - Common ear diseases and hearing loss > Flashcards

JC97 (ENT) - Common ear diseases and hearing loss Flashcards

1
Q

Anatomical structures involved in conductive vs sensorineural deafness

A

Conductive:
External ear - Eardrum - Ossicles

Sensorineural:
Cochlea - Auditory nerve - Brainstem

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2
Q

Ddx Conductive deafness

A

Sound cannot be transmitted to inner ear, e.g. mechanical blockage:

Middle ear: 
 Eardrum perforation
 Ossicular chain problem
 Chronic infection (ossicular joint erosion)
 Iatrogenic damage 
 Otosclerosis (foot plate of stapes)
 Tumor
 Middle ear fluid effusion

External ear canal: congenital meatal stenosis/ meatal atresia/ microtia/ deformities e.g. cauliflower ear
Otitis externa
Wax impaction
Foreign body obstruction

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3
Q

Ddx sensorineural deafness

in children and adults

A

Children:
 Born profoundly deaf, genetic
 Neonatal (e.g. uncontrolled neonatal jaundice)

Adult:
 Meningitis
 Noise (occupation: long exposure damages hair cell)
 Inner ear dysplasia/ deficient inner ear

Damage to inner ear:
 Ear/ head trauma
 Drug-induced, e.g. TB drugs (injection of gentamicin)
 Chronic ear infection
 Cochlear otosclerosis
 Radiotherapy
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4
Q

Clinical assessment of hearing loss

Thresholds assessed

A

Pure tone audiogram (PTA)

Air conduction (AC) threshold - softest sound heard through external auditory canal

Bone conduction (BC) threshold - Vibrator on skull, usually mastoid process

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5
Q

Quantify severities of hearing loss in dB

Effect of deafness on daily life

A

 Mild: 20-40dB (e.g. cannot hear bird sing)
 Moderate: 40-70dB
 Severe: 70-90dB
 Profound hearing loss: >90dB (e.g. cannot hear dog bark)

Childhood onset: Poor development of speech and language, education

Adult: Poor communication for social, occupational activities. Socioeconomic and safety concerns

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6
Q

Ddx malformations and diseases at the auricle of external ear

A

Congenital malformations:

  • Preauricular sinus
  • Accessory auricle
  • Bat ear (most common)
  • Microtia, Meatal atresia

Disease:

  • Pinna keloid
  • Perichondritis
  • Herpes zoster vesicles
  • Pinna carcinoma: SCC and BCC
  • Haematoma auris
  • Cauliflower ear
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7
Q

Preauricular sinus

  • Pathogenesis
  • Complications
A

 Hole (sinus opening) in anterior pinna

 Due to improper fusion of 6 auditory hillocks during embryonic development of auricle

Cx: Discharge and infection

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8
Q

Accessory auricle

Pathogenesis
Effect on hearing

A

improper fusion of 6 auditory hillocks during embryonic development of auricle

 No effect on hearing
 Effect on cosmesis, may be removed

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9
Q

Microtia and meatal atresia

Describe malformation
Effect on hearing

A

 Severe deformity of pinna (external ear) increases the likelihood of deformity in middle ear

 meatal atresia = no opening to middle ear at all = likely conductive deafness

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10
Q

Pinna keloid

Cause
Effect

A

 Due to trauma (common esp in young ladies/ gentlemen with ear piercing at cartilage)

 Infection = pinna keloid

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11
Q

2 infections of the auricle/ pinna of external ear

A

Perichondritis - infection of the cartilage of pinna

Herpes zoster vesicles: Reactivation of varicella zoster

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12
Q

Herpes zoster vesicles on pinna of external ear

  • Cause
  • Major complications
A

Reactivation of varicella zoster

Ramsay Hunt Syndrome:

  1. Vesicles on pinnae/ external auditory canal
  2. Sensorineural hearing loss and peripheral vertigo
  3. Facial paralysis
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13
Q

Haematoma auris

  • Cause
  • Complication
A

Cause:

  • Trauma causes blood to pool under perichondrium
  • Swelling of pinna causes loss of curvature

Complication:
- Cartilage without blood supply from perichondrium&raquo_space; cartilage necrosis and permanent deformity

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14
Q

Cauliflower ear

  • Cause
  • Effect on hearing
A

severely deformed pinna due to repeated trauma, delayed treatment

Traumatic pinna deprived of blood supply becomes necrotic

No effect on hearing, just cosmesis

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15
Q

Ddx lesions in the external ear canal

A
  • Otitis externa
  • Impacted wax
  • Foreign body obstruction
  • Osteoradionecrosis
  • Aural polyp
  • Squamous cell carcinoma (skin cancer)
  • Metastatic tumor from parotid gland
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16
Q

Impacted ear wax

  • Physiological production of ear wax
  • Effect on hearing
A

Wax = normal secretion with antiseptic property, normally pushed out spontaneously by pars tensa epithelium

Infected wax can exacerbate impaction

Conductive deafness

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17
Q

Foreign body obstruction in external ear canal

  • Common objects
  • Treatment for insect obstruction
A

cotton wool, plastic beads, tissue paper, Lego, earring, batteries

Treatment for insect: pour oil to suffocate it before removal

18
Q

Osteoradionecrosis of external ear canal

  • Most common cause
  • Effect on hearing
A

Very common after H&N irradiation due to NPC

Necrosis of soft tissue and bone complicated by infection, discharge,

Hearing loss; Conductive, sensorineural, mixed

19
Q

Otitis externa

  • Common causative pathogens
  • Common anatomical location affected
  • Triggers/ predisposing factors
A

Pathogen:

  • Staphylococcus aureus (from skin)
  • Fungal

Anatomical extent:

  • Diffuse (from skin infection)
  • Localized Furunculosis at cartilaginous part of EAC
Triggers for S. aureus: 
 Narrow ear canal (congenital, trauma)
 Skin disease, e.g. eczema
 Diabetes mellitus
 Humidity (“Singapore Ear”)
 Impacted ear wax
 Foreign body
 Water (swimming, shower)
 Abrasion (scratching, pricking)

Trigger for fungal: overuse of antibiotic eardrops

20
Q

Otitis externa

Presentation

A

Pain, discharge, NO hearing loss

 Note: external ear diseases seldom is the sole cause of hearing problem
(unless totally impacted wax)
 E.g. otorrhoea + conductive deafness = ook for middle ear problems

21
Q

Otitis externa

Treatment options

A

 Local cleansing (remove wax/ foreign body, suction clearance)

 Keep away from moisture (not to swim for 2-3 weeks)

 Local antibiotic eardrops against Staphylococcus (e.g. cloxacillin, cephalexin); Antifungals

 Correct causes: small meatus, osteoma

22
Q

Ddx middle ear lsions

A

Infection:
Acute otitis media and chronic suppurative otitis media
Otitis media with effusion (blocked Eustachian tube)

Trauma:
Traumatic perforation
Hemotympanum

Tumor:
Glomus tumor
Facial nerve neuroma

Congenital Cholesteatoma
Benign tympanosclerosis

23
Q

Acute otitis media

  • Source of infection
  • Causative pathogens
  • S/S
A

Ascending infection from nasopharynx via eustachian tube

Causative pathogens:

  • Most viral
  • Bacterial: Strep. pneumoniae, H. influenzae, Moraxella catarrhalis
S/S: 
 Pain 
 Conductive deafness
 Constitutional symptoms (fever)
 No otorrhea unless eardrum perforated (late stage) (cf CSOM)
24
Q

Chronic suppurative ototis media

Source of infection
Causative pathogens
S/S

A

Source:

  • Severe acute otitis media (ascending infection from nasopharynx)
  • Trauma: mechanical, iatrogenic, barotrauma, blast injury
  • Over-use of antibiotic eardrops causing fungal CSOM
Causative pathogens:
Mixed organisms:
 Staphylococcus aureus
 Pseudomonas aeruginosa
 Escherichia coli
 Bacteroides fragilis
Fungus: aspergillosis, candidiasis
Tuberculosis

S/S:
Recurrent otorrhoea +/- suppuration
Conductive/ mixed hearing loss

25
Q

Acute otitis media

First line investigation and typical findings

A

Otoscopy:
 Redness, congested vessels on eardrum
 Usually: middle ear still filled with air
 Late stage: filled with pus

26
Q

Chronic suppurative otitis media (CSOM)

First- line investigation and typical findings

A

1) Otoscopic exam:
- Persistent, non-healing eardrum perforation
Active CSOM:
- Perforation, discharge, hearing loss&raquo_space; Ear swab and bacteria culture**
Inactive CSOM:
- Perforation without discharge&raquo_space; no need for bacteria culture

2) Audiological assessment: Pure tone audiogram

27
Q

Define the types of eardrum perforation in chronic suppurative otitis media

A

Centra (safe) vs Marginal (unsafe) perforation

Central/ Safe:

  • aka Tubotympanic perforation
  • At pars tensa
  • More common

Marginal Unsafe:

  • akak attic perforation/ atticoantral perforation
  • At rim/ pars flaccida
  • Higher risk of complications e.g. facial nerve palsy, inner ear damage
  • Associated with Cholesteatoma
28
Q

Acute otitis media

Treatment options

A

Oral antibiotics
- Against Gram- positive bacteria: amoxicillin, erythromycin, co-trimoxazole, cefuroxime

Supportive treatment for pain, fever

Drainage myringotomy (refractory/ late stage): drain pus under GA to relieve symptoms and send for culture

29
Q

Chronic suppurative otitis media

Treatment options for safe and unsafe CSOM

A

Local cleansing, ear mopping (remove wax/ foreign body,
suction clearance)

Broad-spectrum antibiotic eardrops (e.g. cephalosporin)

Safe CSOM: Tympanoplasty ,Hearing aid
- Hearing improvement and prevent otorrhoea

Unsafe CSOM: Compulsory mastoidectomy (remove cholesteatoma)
- remove posterior canal and prevent further complications

30
Q

Intracranial complications of Chronic suppurative otitis media

A

 Extradural abscess
 Subdural abscess
 Meningitis
 Brain abscess – temporal lobe, cerebellum

 Sigmoid sinus thrombophlebitis
 Otitic hydrocephalus

31
Q

Extracranial complications of Chronic suppurative otitis media

A

 Facial nerve palsy (CN VII superior to oval window)

 Ossicular chain erosion - more conductive deafness

 Inner ear damage:

  • Labyrinthitis (spread to inner ear) = mixed HL/ total deafness
  • Lateral semicircular canal (LSCC) fistula (superior to oval window)

 Subcutaneous/ subperiosteal abscess

32
Q

Otitis media with effusion

First-line investigation
Pathogenesis

A

Otoscopy: intact eardrum but air-fluid level behind, suggesting effusion in middle ear cavity

Pathology:
o Eustachian tube normally opens during swallowing/ Valsalva’s maneuver
o Obstruction in Eustachian tube due to effusion&raquo_space; hearing loss (conductive/ mixed)

33
Q

Causes of otitis media with effusion/ Eustachian tube blockage

A

Mechanical:

  • Enlarged adenoid/ adenoid hypertrophy (children)
  • NPC (adult)

Poor mucociliary clearance in the ET tube

  • Infection
  • Rhinitis
  • Post-irradiation in H&N cancer

ET tube dysfunction

  • Cleft palate (difficulty opening ET)
  • Post-op iatrogenic damage
34
Q

Traumatic perforation of eardrum

First-line investigation
Prognosis
Management

A

Investigation:
- Otoscopy

Prognosis:
- Natural healing in 3-4 weeks if clean and without infections

Management:

  • Clean and dry
  • Do not clean blood to introduce infections
  • Follow-up hearing loss assessment
35
Q

Haemotympanum

Causes
Effect on hearing
Prognosis

A

Causes:
Trauma to ear
Temporal bone fracture

Hearing: Conductive hearing loss

Prognosis: self-limiting

36
Q

Glomus tumor

Cause
Hearing loss

A

Vascular tumor in middle ear

Conductive hearing loss or mixed in advanced stage (involve inner ear)

37
Q

Ddx inner ear lesions

A
  • Acoustic neuroma at cerebellopontine angle

- Temporal bone fracture

38
Q

Complications of acoustic neuroma

Which nerve does it arise from?

A

3 components in CN VIII – 2 vestibular nerves + 1 auditory nerve:
o Acoustic neuroma usually arises from vestibular part of nerve

Benign (does not metastasize)

Complications:
 Compression on auditory nerve - Sensorineural hearing loss
 Compression on CN V - CN V palsy
 Compression on low cranial nerves (IX, X, XI, XII) - low cranial nerves palsy
 Compression on cerebellum - cerebellar problem

39
Q

Temporal bone fracture

Complications

A

Conductive deafness, e.g. blood in middle ear (haemotympanum), perforated eardrum, fracture line through ossicle chain

Sensorineural deafness: fracture line damages through cochlea

Facial nerve palsy (may be affected by inflammation/ swelling/ fracture)

40
Q

Hearing rehabilitation options

A

Reconstruction of sound conducting mechanism – middle ear surgery:
o Eardrum perforation repair (tympanoplasty for safe CSOM)
o Ossicular chain surgery

Hearing aids

Cochlea implants

41
Q

Types of hearing aids

A 
o BW (body worn) – wire, headphone
o BTE (behind the ear)
o ITE (in the ear)
o ITC (in the canal) – less obvious
o CIC (completely in the canal)
o Meatal atresia  no ear canal  need direct bone conduction at skull
42
Q

Cochlear implant

  • Indications
  • Surgery mechanism
A

 Bilateral profound sensorineural hearing loss (total deaf; no matter how
much amplification)

 No additional benefit from appropriately-fitted hearing aid

Mechanism of cochlear implant
surgery:
 All structures are defective in patient so need to stimulate nerve directly
 Electrode leads to cochlea
 Wear external switch processor  signal sent to device to directly stimulates
cochlea
 info transmitted through CN VIII (auditory nerve) to brain (auditory cortex)

MBBS IV - Junior Clerkship WCS (131 decks)

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