耳鼻喉科Otolaryngology topic twelve: Outer and middle ear diseases

Outer and middle ear diseases

1. Auricle

Blood supply (external carotid a.)

-- occipital a.

-- posterior auricular a. 

-- superficial temporal a. 

Nerve

-- CN5 

-- CN7, 9, 10

-- greater auricular n.

2. External auditory canal

-- external 1/3: cartilage, sebaceous gland, follicle, ceruminous gland

-- internal 2/3: more fragile

-- junction: isthmus, narrowest

3. Auricle diseases

Preauricular sinus

-- Brachial arches fail to fuse.

-- can be bilateral or unilateral

-- treatment: total resection, but  recurrence↑

Microtia

-- male

-- unilateral atresia, right side

-- grade 2: lower part normal; grade 4: combined with other brachial arch problems

-- treatment: early amplification by hearing aid if bilateral (bone transmission)

Perichondritis/chondritis

-- DM, trauma, post-OP

Relapsing polychonditis

-- autoimmune related, idiopathic

-- All cartilages may be affected.

-- earlobe unaffected
-- treatment: steroid

Herpes zoster oticus

-- VZV

-- pain, vesicles after 3~7 days

-- Ramsay-Hunt syndrome: CN7--> facial palsy, open eyes; CN8--> tinnitus, headache, hearing loss; CN9,10

-- treatment: acyclovir/valcyclovir, steroid, ZnO, corneal protection

Malignancy

-- squamous

-- basal cell

-- melanoma

4. External ear canal diseases

Cerumen impaction and foreign body 

Acute otitis externa (swimmer's ear)

-- pain while pulling/pressing auricle

-- microbiology: Pseudomonas, S. aureus (second infection)

-- treatment: topical antibiotics except DM/ immunosupression

Otomycosis

-- NOT related to immune status

-- microbiology: Apergillus, Candida

Necrotizing external otitis

-- extremely painful, seeing granuloma, invading peripheral soft tissues (even skull base!)

-- microbiology: Pseudomonas, MRSA

-- progress quickly

-- exam. tools: Tc99m/CT for bones, Gallium scan for F/U, MRI

-- treatment: antibiotics, surgery

5. Reflexes of the middle ear/ nerve passing
-- CN5-->tensor tympani at neck of malleus-->tighten eardrum
-- CN7--> stapedius m.-->pulling away stapes-->acoustic reflex
-- chorda tympani n.(taste of anterior 2/3 of tongue)->between malleus and incus

6. Middle ear diseases


Eardrum(=tympanic membrane) perforation
-- traumatic: wedge shape
-- central perforation: less likely to develop into cholesteatoma
-- Otic drops: choose quinolones among antibiotics

Atelectatic and adhesive otitis media
-- middle ear negative pressure-->erosion of ossicles

Cholesteatoma
-- epithelium in abnormal middle ear region-->erosion of ossicles
-- congenital or acquired
-- DDx: chronic myringitis, atrophic scar(lacking fibrous tissue)

Acute otitis media

-- children, after URI

-- acute: <3 wks

-- diagnosis triad: acute, middle ear effusion(pus), symptoms

-- cannot rule out polyp, cyst, tumor
-- microbiology: Streptococcus pneumonia, Hemophilus influenza, Moraxella catarrhalis, RSV, inflenza, parainflenza, rhinovirus
-- treatment: amoxicillin, augmentin

Chronic otitis media
-- chronic: >3 months
-- structural change
-- microbiology: Pseudomonas aeruginosa, Staphylococcus aureus, anaerobics

Otitis media with effusion (OME)
-- NO pus, asymtomatic, plugged sensation
-- 6 months~4 y/o , recover in 3 months automatically 
-- chronic if bil. >3 months, uni. > 6 months; recurrent if >4 times in a year, >3 times in 6 months
-- diagnosis tool: pneumatic otoscope
-- DO NOT perform adenoidectomy if first episode
-- DDx: NPC if unilateral in adults

Otosclerosis
-- female > male, whites
-- osseous dyscrasia limited to the temporal bone (affecting otic capsule)
-- 70% bilateral, progressive hearing loss
-- Schwartze’s sign

Temporal bone trauma
-- 30%~75% head injuries, related to motor vehicle accidents
-- longitudinal: 70~90%  
-- transverse: 50% facial nerve injury, more likely to cause hearing loss
-- may lead to BPPV, perilymph fistula

7. Middle ear surgery

Tympanoplasty (Wullstein, 1953)
-- type 1:  connect to malleus
-- type 2:  connect to incus
-- type 3:  classic-->connect to stapes; modified-->place bone strut, stapes(+)
-- type 4:  classic-->connect to foot plate of stapes; modified-->place TORP, stapes(-)
-- type 5a: footplate(-)
-- type 5b: footplate(-), horizontal semicircular canal
-- modified type 3 & modified type 4--> ossiculoplasty, made from Polycel, titanium