Chronic Otitis Media – Mesotympanitis
1. Definition: Chronic Otitis Media (Mesotympanitis), also known as Tubotympanic Chronic Suppurative Otitis Media
(CSOM), is a chronic inflammation of the middle ear (pars tensa) and Eustachian tube, characterized by a persistent or recurrent mucoid discharge through a permanent perforation of the tympanic membrane (TM). It is considered the "safe type" because it does not involve cholesteatoma and has fewer life-threatening complications than atticoantral disease and Epitympantitis.
Etiopathogenesis
Etiology - Usually, a complication of Acute Otitis Media (AOM) or Serous Otitis Media (SOM) that failed to resolve. Persistent Eustachian tube dysfunction
- Pathogens: Often mixed aerobic and anaerobic bacteria, commonly:
- Pseudomonas aeruginosa
- Staphylococcus aureus
- Proteus species
- Klebsiella species
Pathogenesis
- 1. Prolonged Eustachian Tube Dysfunction (ETD): Chronic negative pressure, poor ventilation, and retained fluid in the middle ear.
- 2. Recurrent Infection: Repeated bouts of AOM, often linked to URTIs or water entering the middle ear through the perforation.
- 3. Permanent Perforation: The TM perforation becomes permanent, leading to persistent communication between the external and middle ear.
- 4. Chronic Inflammation: The middle ear mucosa undergoes irreversible changes, becoming thickened, edematous, and hyperplastic (polypoid changes), leading to chronic mucopurulent discharge.