Examination Questions for Chronic Suppurative Otitis Media
An examiner should focus on questions that assess understanding of CSOM's definition, diagnostic criteria, pathophysiology, and management strategies, with particular emphasis on distinguishing it from other forms of otitis media and recognizing its serious complications.
Core Definitional and Diagnostic Questions
What is CSOM and how is it defined?
CSOM is chronic inflammation of the middle ear and mastoid mucosa with a non-intact tympanic membrane (perforation or ventilation tube) and persistent ear discharge 1. The examiner should probe whether the candidate understands that:
- There is no consensus on duration of discharge needed for diagnosis, with recommendations ranging from 2 weeks to at least 3 months 1
- The tympanic membrane must be perforated or have a ventilation tube 1
- It represents a polymicrobial infection often involving Pseudomonas and Staphylococcus aureus 2
How do you differentiate CSOM from other forms of otitis media?
The candidate must distinguish:
- AOM: Rapid onset with signs of acute inflammation, intact or bulging tympanic membrane 1
- OME: Fluid present but no signs of acute infection and intact tympanic membrane 1
- CSOM: Chronic discharge through a perforated membrane 1
Clinical Presentation Questions
What are the predominant symptoms?
Ear discharge (otorrhoea) and hearing loss are the cardinal features 1. The examiner may ask about:
- Character and duration of discharge
- Presence of conductive hearing loss
- Absence of acute pain (unlike AOM)
What complications should you screen for?
The candidate must recognize both local and systemic complications:
- Life-threatening intracranial complications: meningitis, brain abscesses 1
- Acute mastoiditis 1
- Hearing impairment and disability - CSOM is a leading cause of pediatric hearing loss globally, affecting up to 330 million people 2
- Estimated 21,000 deaths annually from OM complications, particularly in low-income countries 1
Diagnostic Approach Questions
What examination findings confirm CSOM?
The examiner should expect specific otoscopic findings:
- Tympanic membrane perforation with visible discharge 1
- Assessment of middle ear mucosa inflammation
- Evaluation for cholesteatoma (if present, changes management)
What diagnostic modalities are used?
- Pneumatic otoscopy: assesses tympanic membrane mobility 1
- Tympanometry: type B tympanogram indicates middle ear effusion 3
- Audiometry: documents conductive hearing loss 1
- Culture of discharge (though not routinely mentioned in guidelines, important for antibiotic selection)
Pathophysiology Questions
What is the role of biofilms in CSOM?
Bacterial biofilms are present in CSOM and protect bacteria against antibiotics and host immune responses 1. The candidate should understand:
- Biofilms involve bacteria embedded in extracellular matrix adherent to middle ear mucosa 1
- This explains treatment failure and antibiotic tolerance 2
- Persister cells within biofilms are antibiotic-tolerant and can proliferate, gaining additional resistance 2
What is the relationship between viral and bacterial infection?
While more relevant to AOM, understanding the cascade helps:
- Viral URTI precedes bacterial infection in acute cases 1
- Eustachian tube dysfunction facilitates bacterial ascent 1
Management Questions
What is first-line treatment for CSOM?
Topical quinolone antibiotics (ciprofloxacin or ofloxacin) have the strongest evidence 4, 5. Specifically:
- Topical quinolones likely increase resolution of ear discharge at 1-2 weeks compared to boric acid (RR 1.86; one additional person achieves dry ear for every 4 treated) 5
- Topical antibiotics may be more effective than placebo when combined with aural toilet 4
What is the role of aural toileting?
Ear cleaning (dry mopping or antiseptic washouts) is essential 3. The candidate should know:
- Regular cleaning until discharge resolves 3
- Can use povidone-iodine washouts 3
- Often combined with topical antibiotics
When are topical antiseptics used?
Boric acid in alcohol with dry mopping may help resolution compared to dry mopping alone 6, though evidence is very uncertain. Options include:
- Acetic acid
- Boric acid
- Povidone-iodine
- Aluminium acetate
What is the role of systemic antibiotics?
The evidence for systemic antibiotics alone is very uncertain 7. Key points:
- When added to topical antibiotics, there may be little or no difference in resolution 7
- Oral ciprofloxacin with topical ciprofloxacin shows no additional benefit (RR 1.05) 7
- Consider when topical therapy fails or complications suspected
When is surgical intervention indicated?
Surgery should be considered earlier in refractory cases to:
- Minimize antibiotic resistance risk 2
- Maximize ability to debride biofilm 2
- Options include tympanoplasty or tympanomastoidectomy 2
Treatment Failure Questions
Why do topical fluoroquinolones frequently fail long-term?
Treatment failure is secondary to persister cells that are antibiotic-tolerant 2. The candidate should understand:
- Persister cells can proliferate and gain additional resistance 2
- Biofilms are not routinely tested in clinical practice 2
- This explains the need for prolonged treatment or surgical debridement
What are alternatives when first-line treatment fails?
The algorithm should be:
- Ensure adequate aural toileting
- Consider culture-directed therapy
- Trial topical antiseptics (boric acid)
- Refer for surgical intervention rather than prolonging ineffective antibiotic therapy 2
Special Population Questions
How does management differ in Indigenous populations?
While not extensively covered in the evidence, the examiner may ask about:
- Higher prevalence in Indigenous Australian children 1
- Environmental risk factors 1
- National guidelines recommend antibiotic therapy for Indigenous children with AOM 3
What about children versus adults?
CSOM is a leading cause of pediatric hearing loss 2. Consider:
- Impact on language development and school performance 1
- Lower threshold for intervention in children with developmental concerns
- Audiological evaluation essential 3
Prognostic Questions
What determines prognosis?
- Duration of disease (chronic cases have lower spontaneous resolution rates) 1
- Presence of cholesteatoma (requires surgical management)
- Access to treatment (complications more common in low-income countries) 1
- Global prevalence of OM-associated hearing loss: 30 per 10,000 1
Common Pitfalls to Avoid
The examiner may probe understanding of these errors: