Chronic Suppurative Otitis Media (CSOM)
High-Yield Revision Notes for NEET PG / NEXT
CSOM is a long-standing, chronic inflammation of the middle ear and mastoid cavity characterized by a permanent perforation of the tympanic membrane (TM) and persistent or recurrent ear discharge (otorrhea) lasting greater than 6 to 12 weeks.
Clinical Comparison: Tubotympanic type presents with a safe, central perforation (intact annulus), whereas Atticoantral type presents with an unsafe marginal/attic perforation.
Microbiology
Unlike acute otitis media (AOM), the bacteriology of CSOM is dominated by opportunistic environmental pathogens:
- Pseudomonas aeruginosa: The single most common causative organism isolated worldwide.
- Staphylococcus aureus: The second most common aerobic isolate.
- Anaerobes & Fungi: Bacteroides, Proteus, and fungi like Aspergillus or Candida are frequently found in mixed biofilms.
The Two Core Clinical Types
Examiners frequently target the differentiating clinical features between the “Safe” and “Unsafe” varieties:
| Feature | Tubotympanic Disease (“Safe / Benign”) | Atticoantral Disease (“Unsafe / Dangerous”) |
|---|---|---|
| Pathology Location | Anteroinferior part of the middle ear cleft (Eustachian tube and hypotympanum). | Posterosuperior part of the cleft (Attic, antrum, and mastoid). |
| TM Perforation | Central perforation (perforation is surrounded by a rim of intact TM; does not involve the fibrocartilaginous annulus). | Marginal or Attic perforation (involves the annulus or pars flaccida). |
| Otorrhea Nature | Profuse, mucoid or mucopurulent, intermittent, and non-foul-smelling. Spikes during URTIs. | Scant, purulent, continuous, and profoundly foul/putrid smelling (due to bone necrosis). |
| Associated Findings | Edematous or pale middle ear mucosa; pale polyps may track through the hole. | Presence of cholesteatoma flakes, granulation tissue, or a red, vascular attic polyp. |
| Complications Risk | Extremely low or rare. | Very high risk for life-threatening intra- and extracranial complications. |
Diagnostic Workup
- Examination Under Microscope (EUM): Mandatory step to clear debris, accurately inspect the margins of the perforation, assess the status of the ossicular chain, and rule out microscopic cholesteatoma pockets.
- Ear Culture and Sensitivity (C&S): Collected after matching a dry-ear interval window or before initiating targeted topical antimicrobial therapy.
- Pure Tone Audiometry (PTA): Typically reveals mild-to-moderate Conductive Hearing Loss (CHL). A sudden switch or progression to mixed hearing loss indicates inner ear involvement (toxins penetrating the round window).
- High-Resolution CT (HRCT) of the Temporal Bone: Imperative for the Atticoantral variety to check for ossicular erosion, status of the facial canal, and tegmen integrity.
Management Protocol
1. Medical Treatment (Primarily for Tubotympanic / Dry-Ear Prep)
- Aural Toilet: Thorough mechanical removal of all discharge, crusts, and debris from the external canal. This is the single most vital prerequisite for topical medications to work.
- Topical Antibiotics: Otic drops containing fluoroquinolones (e.g., Ofloxacin or Ciprofloxacin) are preferred due to excellent anti-pseudomonal coverage. Aminoglycoside drops must be used with caution in open ears due to the theoretical risk of cochleotoxicity.
- Dry Ear Precautions: Patients must strictly prevent water entry during bathing/swimming using custom silicone plugs.
2. Surgical Management (Definitive Curative Route)
- Myringoplasty: Surgical repair restricted strictly to closing a perforation of the tympanic membrane pars tensa, without checking or manipulating the underlying ossicles.
- Tympanoplasty: Reconstruction of the tympanic membrane combined with the evaluation and/or reconstruction of the ossicular chain (Ossiculoplasty). The single most commonly used autologous graft material is the Temporalis Fascia (due to its low basal metabolic rate, similar thickness, and proximity to the surgical field).
- Mastoidectomy: Always required for Atticoantral disease to clear out infected air cell matrices or expanding cholesteatoma sacs. Often combined with tympanoplasty (Tympanomastoidectomy).