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Otitis Media - FMGE High-Yield Integrated Notes

1. ANATOMY INTEGRATION (Gray's Anatomy / Cummings)

Eustachian (Auditory) Tube - The Key Structure

• The ET opens into the nasopharynx - adenoid hypertrophy blocks the ET orifice → OM
• Muscles involved in ET opening: Tensor veli palatini (main) and Levator veli palatini - both from the mandibular nerve (V3) and pharyngeal plexus
• Cleft palate → tensor veli palatini dysfunction → chronic ET dysfunction → OME (FMGE favorite)
• The ET lining is pseudostratified ciliated columnar epithelium (same as respiratory tract - important in pathogenesis)

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2. CLASSIFICATION OF OTITIS MEDIA

OTITIS MEDIA
├── Acute Otitis Media (AOM) — < 6 weeks duration
├── Otitis Media with Effusion (OME) / "Glue Ear" / "Serous OM"
│   — non-purulent fluid, no acute inflammation
└── Chronic Otitis Media (COM)
    ├── Chronic Active OM
    │   ├── WITH Cholesteatoma (unsafe/dangerous type)
    │   └── WITHOUT Cholesteatoma (tubotympanic/safe type)
    └── Chronic Inactive OM
        ├── With perforation
        ├── With retraction pocket
        └── Adhesive OM

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3. MICROBIOLOGY INTEGRATION

AOM (Bacterial Pathogens - Classic Triad)

• Mnemonic: "She Has More" (S. pneumo > H. flu > M. catarrhalis)
• Viral precursors: RSV, Rhinovirus, Coronavirus, Influenza A, Adenovirus, Parainfluenza
• Fungal OM: Aspergillus, Candida - think immunocompromised patients

COM (CSOM) Organisms

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4. PATHOPHYSIOLOGY INTEGRATION

Stages of AOM (Pathology correlation)

1. Hyperemia stage - mucosal congestion, ET blockade
2. Exudation stage - serous exudate → PMNs infiltrate → middle-ear pressure rises
3. Suppuration stage - pus forms; TM bulges
4. Resolution - pus resorbs OR TM perforates → discharge (pressure relief)
5. If effusion persists after resolution → OME

Histology of AOM (Shambaugh)

• Hematoxylin & eosin: acute inflammatory exudate with PMNs + eosinophilic secretions in middle ear space
• Mucosal lining and TM are thickened
• Process extends into mastoid air cells (all AOM has some degree of radiological mastoiditis)

OME Pathophysiology

• ET dysfunction → inadequate gas exchange → negative middle-ear pressure → transudate formation
• Pepsin/pepsinogen detected in middle-ear effusions → possible role of GERD (Scott-Brown's)
• Low pH reduces ciliary motility → worsens ET drainage
• GERD prevalence in OME: 17.6-64% (clinical pearl for FMGE)

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5. CLINICAL FEATURES

AOM

• Otalgia (ear pain) - most prominent symptom
• Fever
• Conductive hearing loss
• Purulent otorrhea if TM ruptures
• Otoscopy: TM erythematous + bulging (the two cardinal signs)
• Tympanometry: flat (Type B) tympanogram + absent acoustic reflexes
• Audiometry: conductive hearing loss

Bullous Myringitis

• Bullae on TM - associated with AOM
• Previously attributed to Mycoplasma pneumoniae (OUTDATED) - now known to be typical AOM organisms
• Treatment same as AOM (FMGE frequently tests this)

OME ("Glue Ear")

• Painless hearing loss in a child (often incidental)
• TM: retracted, amber-colored, air-bubble visible behind it
• Type B tympanogram (flat) but without features of acute infection
• Most common cause of acquired conductive hearing loss in children

COM - SAFE TYPE (Tubotympanic/Mucosal)

• Central perforation of TM (pars tensa)
• Mucoid/mucopurulent discharge
• Conductive hearing loss
• No cholesteatoma, no bone erosion
• Treatment: conservative (Dry mopping + topical antibiotics), surgery if persistent

COM - UNSAFE TYPE (Atticoantral/Cholesteatoma)

• Attic perforation (pars flaccida / Shrapnell's membrane) OR posterior marginal perforation
• Foul-smelling scanty discharge (keratin debris)
• Conductive hearing loss (mixed if labyrinthine fistula)
• Aural polyp - highly suggestive of cholesteatoma
• FMGE key: Chronically draining ear not responding to antibiotics → think cholesteatoma

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6. CHOLESTEATOMA (Integrated Pathology)

Definition

• "Benign tumor" of stratified squamous epithelium in middle ear/mastoid
• Produces and accumulates desquamated keratin debris
• Annual incidence: 3/100,000 children, 9.2/100,000 adults (slight male predominance)

Types

Theories of Pathogenesis (FMGE)

1. Immigration theory - squamous epithelium migrates through perforation
2. Invagination/retraction pocket theory (most accepted) - retraction of pars flaccida into middle ear
3. Metaplasia theory - mucosal metaplasia after chronic infection
4. Implantation theory - traumatic or surgical implantation

Bone Erosion Mechanism

• Initially affects ossicular chain and scutum
• Expands to: otic capsule, fallopian canal, tegmen
• Mechanism: inflammatory mediators (macrophages, monocytes), osteoclasts responsible for resorption
• Mast cells increased in granulation tissue along eroded surfaces

Imaging

• CT temporal bone = investigation of choice (shows bony erosion, soft tissue)
• MRI - NOT useful for bone detail; used for intracranial complications assessment

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7. COMPLICATIONS (Integrated Anatomy + Surgery)

Intratemporal Complications

Intracranial Complications

Facial Nerve Palsy in OM (Neurology Integration)

• AOM: direct extension through Fallopian canal dehiscences, bacterial toxins causing demyelination, ischemia of vasa nervorum
• CSOM: compression by cholesteatoma (most likely) or inflammation
• "Facial paralysis + CSOM = suspect cholesteatoma until proven otherwise" - immediate surgical decompression

Mastoiditis - Key Clinical Distinction (FMGE favorite)

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8. PHARMACOLOGY INTEGRATION (Goodman & Gilman / Tintinalli / Harriet Lane)

Treatment Algorithm - AOM

• Immediate antibiotics for:
  • All infants < 6 months
  • Severe symptoms (pain ≥48 h, fever >39°C)
  • Bilateral AOM in children < 24 months
  • Recurrent AOM (episode within 2-4 weeks)
  • AOM with perforation
  • Immunocompromised patients
  • Craniofacial abnormalities
• Watchful waiting (2-3 days) acceptable for:
  • Children ≥24 months with unilateral AOM, mild symptoms, fever <39°C
  • NOT validated in adults

Antibiotic Regimens (Tintinalli)

Antibiotic Failure Management

• After failure of first-line amoxicillin → Amoxicillin-clavulanate (covers beta-lactamase producers: H. flu, M. catarrhalis)
• After failure of 2nd line → Ceftriaxone IM × 3 days or ENT referral for myringotomy

CSOM Topical Treatment

• Safe type (tubotympanic): Topical antibiotics (ciprofloxacin drops) + Dry mopping + Aural toilet
• Aminoglycosides (neomycin, gentamicin): ototoxic - avoid if TM perforation
• Systemic antibiotics: Only for exacerbations

Malignant Otitis Externa

• Organism: Pseudomonas aeruginosa (Aspergillus in immunocompromised)
• Patient: Elderly + poorly controlled diabetic (immunocompromised)
• Treatment: Ciprofloxacin 750 mg PO BD × minimum 6-8 weeks
• Facial palsy = advancing infection → poor prognosis
• CT: bony erosion of skull base

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9. PEDIATRICS INTEGRATION (Harriet Lane)

Age-Related Risk Factors for AOM

• Peak incidence: 6 months - 2 years
• Day-care attendance, bottle feeding, passive smoking, cleft palate
• Breast feeding is protective

Recurrent AOM Definition

• ≥3 episodes in 6 months OR ≥4 episodes in 12 months

OME and Language Delay

• OME → persistent conductive hearing loss → speech and language delay
• The OM-6 questionnaire assesses: physical suffering, hearing loss, speech impairment, emotional distress, activity limitation, caregiver concerns

Grommets (Tympanostomy Tubes) - Indications

• Recurrent AOM (≥3 in 6 months or ≥4 in 12 months)
• OME with hearing loss >25 dB lasting ≥3 months
• At-risk child (cleft palate, Down syndrome)
• Post-grommet: treat otorrhea with ototopical fluoroquinolone (ofloxacin) drops - NOT systemic antibiotics as first line

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10. ENT SURGERY INTEGRATION

Myringotomy

• Incision in the anteroinferior quadrant of TM (safest area - away from ossicles, chorda tympani, facial nerve)
• Done under local (adults) or general (children) anesthesia
• Indications: AOM not responding to antibiotics, severe pain, facial palsy, intracranial complication

Tympanoplasty

• Repair of TM perforation
• Success rate: >90% (Harrison's)
• Types (Wullstein classification):
  • Type I (Myringoplasty): TM repair only, ossicles intact
  • Type II: TM + ossicular repair with malleus erosion
  • Type III: Myringostapedopexy (malleus + incus absent, stapes intact)
  • Type IV: Stapes footplate only mobile
  • Type V: Stapes footplate fixed, semicircular canal fenestration

Mastoidectomy

• Cortical (simple) mastoidectomy: removes air cells, preserves posterior canal wall - for AOM complications
• Modified radical mastoidectomy: removes posterior canal wall - for cholesteatoma
• Radical mastoidectomy (Bondy): removes middle ear contents + posterior wall

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11. HEARING LOSS INTEGRATION (Cummings / Harrison's)

• SNHL is rarely associated with AOM directly (Cummings)
• Long-standing COM: mixed hearing loss - whether SNHL is due to infection itself or ototoxic drugs/surgery is debated

Tympanometry Types

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12. CROSS-SUBJECT HIGH-YIELD INTEGRATION TABLE

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13. FMGE FAVORITE BUZZWORDS & ONE-LINERS

1. Safest quadrant for myringotomy = Anteroinferior
2. Most common complication of AOM = Mastoiditis
3. Most common intracranial complication of OM = Meningitis
4. Cholesteatoma imaging = CT temporal bone
5. Cholesteatoma - unsafe ear = Attic/atticoantral/pars flaccida perforation
6. Safe ear = Tubotympanic/central/pars tensa perforation
7. Glue ear (OME) = most common cause of acquired conductive HL in children
8. Foul-smelling scanty discharge + aural polyp = Cholesteatoma until proven otherwise
9. Pearly white mass behind intact TM in child = Congenital cholesteatoma
10. Fluoroquinolone drops = Safe with TM perforation; aminoglycosides = NOT safe
11. Gradenigo's syndrome = Otitis media + CN VI palsy + retroorbital pain (petrous apex)
12. Malignant OE = Elderly diabetic + Pseudomonas + skull base osteomyelitis + CN VII palsy
13. GERD + OM = Pepsin/pepsinogen found in middle ear effusion
14. Cleft palate = Tensor veli palatini dysfunction → chronic OME
15. Ramsay Hunt syndrome = VZV + facial palsy + ear vesicles (NOT OM, but tested alongside)
16. After grommet insertion = Treat otorrhea with ototopical fluoroquinolone drops
17. Bullous myringitis = Treat same as AOM; NOT specifically Mycoplasma (outdated)
18. Highest spontaneous resolution = M. catarrhalis
19. Most serious organism in AOM = S. pneumoniae (most complications)
20. Combined conjunctivitis + otitis = H. influenzae; treat with amoxicillin-clavulanate

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14. QUICK RECALL MNEMONICS

• S = Streptococcus pneumoniae (most common)
• H = Haemophilus influenzae
• M = Moraxella catarrhalis

• Mastoiditis
• Facial palsy
• Labyrinthitis
• Petrositis (Gradenigo's)

• Meningitis (most common)
• Lateral sinus thrombosis
• Extradural abscess
• Subdural abscess
• Otitic hydrocephalus

• I: TM repair only
• II: Malleus involved
• III: Incus involved (myringostapedopexy)
• IV: Stapes footplate only
• V: Footplate fixed, fenestration

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• Shambaugh Surgery of the Ear (classification, cholesteatoma, OME)
• Cummings Otolaryngology Head & Neck Surgery (AOM stages, hearing loss)
• Tintinalli's Emergency Medicine (treatment algorithms, antibiotic tables)
• Harrison's Principles of Internal Medicine 22E (conductive HL, ET dysfunction)
• Scott-Brown's Otorhinolaryngology Vol 1 & 2 (GERD-OM link, facial palsy, complications)
• Harriet Lane Handbook 23e (pediatric dosing, high-dose amoxicillin)
• Goodman & Gilman's Pharmacological Basis (amoxicillin, ampicillin indications)
• Gray's Anatomy for Students (ET anatomy)