Otitis Media

Question 1

Peak age prevalence of OM

Answer 1

6-18mo

Question 2

Aetiology of OM

Answer 2

• viral (25%)
  • RSV
• Bacterial (75%)
  • Streptococcus pneumoniae
  • Moraxella catarrhalis
  • non-typable strains of Haemophilus influenzae

Question 3

List some risk factors for OM

Answer 3

• Aboriginal
• Eustachian tube dysfunction
• Passive smoking, smoke exposure
• Down syndrome (due to different anatomy of Eustachian tube)
• Cleft palate (95% require grommets long-term)
• Using a pacifier
• Cystic fibrosis
• Primary ciliary dysfunction
• GORD
• Immunoglobulin deficiency

Question 4

Cf pathophysiology of OM vs otitis externa.

Answer 4

• OM: eustachian tubes in children are more horizontal, making it easier for bacteria to enter middle ear from nasopharynx, and harder for them to exit!
• Otitis externa: usually due to excess moisture in the canal, e.g. after swimming, or damage to the canal after use of cotton buds or scratching.

Question 5

List some clinical features of OM.

Answer 5

• Triad of:
  • Otalgia esp. pulling at ear/irritability in pre-verbal children
  • fever (especially in younger children)
  • conductive hearing loss

• May have:
• Anorexia
• rarely tinnitus, vertigo, and/or facial nerve paralysis
• otorrhea if tympanic membrane perforated
• Associated viral Sx: coryza, red tonsillopharynx, cough, lethargy etc.
• Sx more associated with bacterial infection:
○ Yellow discoloration/discharge
○Vomiting

Question 6

What are some findings on otoscopy in OM?

Answer 6

• The usual middle ear landmarks (handle of malleus, incus, light reflex) are not well seen
• Injected vessels
• Convex TM
• TM opacification and myringitis (erythema), bulging with marked discoloration (e.g. haemorrhagic, grey, yellow)
• Air fluid level may be seen

Question 7

List some complications of OM

Answer 7

• Hearing loss
• Chronic otitis media/recurrent otitis media (ROM)
  
  • Esp. cholesteatoma
• Febrile convulsions
• Suppurative complications uncommon:
  
  • mastoiditis, suppurative labyrinthitis or intracranial infection (meningitis, extradural or subdural abscess, brain abscess)
• facial nerve palsy
• lateral sinus (venous) thrombosis
• benign intracranial hypertension
• Infection of grommet

Question 8

How do we manage acute OM? How does this differ from otitis externa?

Answer 8

• 80% cases of AOM in children resolve spontaneously (regardless if viral/bacterial)
• Cf otitis externa: always need to be treated with abx drops
• > 12mo, mildly unwell: analgesia paracetamol 24-48h -> amoxy if not improving
• <12mo: amoxy 15mg/kg/dose TDS 5 days
• If not improving, review Dx or switch co-amoxyclav
• Advise parents to r/v if persistent irritability/hearing diff/ear Sx after 2-3 months

Question 9

What are some common forms of chronic OM?

Answer 9

Tympanosclerosis

Adhesive otitis media
• End-stage glue ear
• No middle ear space remaining
• Grommet will most likely be ineffective

Chronic suppurative otitis media
• Perforations of ear drum
• Discharge in middle ear
• Treated by grafting procedure

Cholesteatoma
• Most serious form
• Collection of keratin and skin
• Begins with retraction pockets due to negative pressure→desquamation of skin into pocket, which gradually enlarges and has a destructive process of the structures in the middle ear

Question 10

What are risk factors for OM with effusion?

Answer 10

• Parental smoking**

* Limit dummy use for settling

Question 11

How can we manage OM with effusion?

Answer 11

Grommet stays in for 9-12 months→automatically pushed out into the ear canal when ear drum grows over