Chronic middle ear infections and perforations of the eardrum caused by trauma or ear surgeries that do not heal spontaneously or with simple interventions are among the most common chronic middle ear diseases. The eardrum is located at the end of the external ear canal and separates the middle ear from the outer ear. Sound waves traveling through the external ear canal vibrate the eardrum, and these vibrations are transmitted to the malleus, followed by the incus and stapes, thereby transferring sound to the inner ear. The Eustachian tube, which connects the middle ear to the nasopharynx behind the nasal cavity and equalizes the pressure in the middle ear with the external atmospheric pressure, and the air cells located within the mastoid bone behind the ear that communicate with the middle ear, constitute the other anatomical structures of the middle ear.
What are the types of chronic middle ear infection?
Chronic middle ear infections have many different types, and in practice, two clinical presentations are encountered most frequently.
Water entering the middle ear through the perforation or infections reaching the middle ear from the sinuses, nose, or nasopharynx through the Eustachian tube may cause intermittent purulent ear discharge. Due to recurrent infections, hearing may gradually deteriorate over time. This group represents the more commonly encountered chronic middle ear problems in clinical practice and is relatively easier to treat, with more successful functional outcomes.
The second important type of chronic middle ear disease is generally associated with dysfunction of the Eustachian tube beginning in childhood. The disease starts with the collapse of the eardrum toward the middle ear due to negative pressure resulting from impaired ventilation of the middle ear. Following the retraction and pocket formation of the eardrum, the skin of the external ear canal progresses into the middle ear and eventually into the adjacent mastoid bone, leading to the formation of an inflammatory mass called cholesteatoma.
The cholesteatoma mass, which contains shed skin cells from the ear canal that have progressed into the ear as well as bacteria proliferating in this environment, causes erosion of the surrounding bones through pressure and inflammatory effects. In this way, it may spread to neighboring structures and lead to serious complications.
There is usually a history of long-standing and progressively worsening hearing loss together with intermittent foul-smelling ear discharge. Patients may present to the hospital with serious ear-related complications such as sudden hearing loss, dizziness, or facial paralysis, or with severe intracranial complications caused by the spread of infection into the skull, such as meningitis or brain abscess.
The primary goal of the surgical treatment of chronic middle ear infections with cholesteatoma is to eliminate the infection. In these patients, the hearing outcomes achieved are generally not as satisfactory as those in the first group.
