Chronic Suppurative Otitis Media (CSOM)

Definition

Epidemiology

• Most common in children under 2 years of age
• Disproportionately affects populations with limited healthcare access and low socioeconomic status
• Higher incidence in Native Americans, Inuit, Indigenous Australians and Māori populations (genetic predisposition)

• Multiple prior episodes of acute otitis media (AOM), especially in the first months of life
• Chronic secretory OM
• Eustachian tube (ET) dysfunction
• Nasopharyngeal reflux
• Tympanostomy tube or pre-existing TM perforation

Classification (Two Types)

Pathogenesis

1. Impaired aeration of ME → negative ME pressure
2. Nitrogen-absorbing mastoid cells further reduce ME volume
3. TM retraction → perforation (pars tensa = tubotympanic; pars flaccida = atticoantral)

• Highly organised networks of sessile bacteria, often polymicrobial
• Protected by an extracellular matrix of oligosaccharides
• Escape phagocytosis, humoral immunity, and antibiotic penetration
• Produce efflux pumps, have altered gene expression and decreased metabolic rate
• Can be adherent to respiratory epithelium, within mucus, or intracellular

Microbiology

Clinical Features

• TM perforation — compensatory mechanism to allow ME aeration
• Chronic/recurrent otorrhea — often malodorous
• Hearing loss — typically low-frequency conductive or mixed
• Aural fullness
• Inflammation of ME mucosa
• Granulation tissue / aural polyps — often obscuring anatomical landmarks; should be considered cholesteatoma until proven otherwise
• TM retraction pockets ± cholesteatoma

Complications

• Facial nerve paresis/paralysis
• Labyrinthine fistula → vertigo
• Mastoiditis / subperiosteal abscess
• Petrositis (Gradenigo syndrome: otorrhea + retro-orbital pain + CN VI palsy)

• Brain abscess
• Subdural / epidural abscess
• Meningitis
• Septic thrombosis of intracranial venous sinuses

Diagnosis

1. Otomicroscopy with pneumatic insufflation — identify perforation, cholesteatoma, retraction pockets
2. Audiometry — characterise hearing loss
3. High-resolution CT temporal bones — for surgical planning, complicated CSOM, cholesteatoma, or revision cases
4. MRI with contrast — if intracranial complications are suspected
5. Biopsy of granulation tissue unresponsive to topical therapy — to exclude malignancy

Key principle: An aural polyp should be considered cholesteatoma until proven otherwise.

Treatment

Goals

• Create a safe, dry ear: no otorrhea; no keratin debris accumulation; reduced risk of suppurative complications

Medical

• Aural toilet (microsuction/syringing) to debride biofilm and debris — critical before topical therapy
• Topical antibiotics (4–6 week course after debridement):
  • Fluoroquinolones (e.g., ciprofloxacin drops) — first line
  • Polymyxin B or neomycin ± steroid
  • Biofilms are frequently resistant; topical therapy has limited efficacy without mechanical debridement
• Acetic acid/alcohol drops (antiseptic)
• Systemic antibiotics have limited role in uncomplicated CSOM

Surgical

• Atticotomy (transcanal)
• Canal wall up (CWU)
• Canal wall down (CWD): radical, modified radical, or Bondy procedure
• Canal wall down with mastoid obliteration

Note: TM perforation closure rates are not increased with concomitant mastoidectomy vs. tympanoplasty alone.

Special Situation: CSOM + Cochlear Implantation

• Historically considered a contraindication; now managed with staged or single-stage protocols
• Ear should be dry at time of implantation
• Options include: myringoplasty → implant (3 months later); radical mastoidectomy + obliteration → implant; or one-stage obliteration + implantation
• All patients receive antimicrobial prophylaxis peri-operatively