Otitis Extern A Case Study

PATHOPHYSIOLOGY
The causes or pathogenesis are usually multifactorial. Several risk factors can predispose to infection or initiate inflammation and subsequently the infectious process. Intact canal skin and cerumen production have a protective effect against infections. This is secondary to the fact that cerumen produces a pH in the ear canal that is slightly acidic. On the other hand, breakdown of skin integrity, insufficient cerumen production, or blockage of the ear canal with cerumen (which promotes water retention) can predispose to infection. Skin integrity can be injured by direct trauma, heat, and moisture or persistent water in the ear canal. Such damage is thought to be necessary for initiation of the inflammatory process. Subsequently, edema may result, followed by bacterial inoculation and overgrowth.
In Otitis Externa, the infection is caused by bacteria or fungi. Scratching, inserting objects into the ear canal, or moisture (from swimming, for example), can make the ear canal vulnerable to infection.

EVALUATION

ANATOMY:
It is divided into a lateral (outer) cartilaginous portion that occupies approximately one-third of the canal and a medial (inner) bony portion that occupies the remaining two-thirds. Their junction is termed the isthmus and is the narrowest region of the ear canal. The outer cartilaginous portion is lined by thicker skin with numerous adnexal structures including cerumen glands, sebaceous glands, and hair follicles. The inner bony portion of the canal contains thin skin without subcutaneous tissue. The dermis in this area is in direct contact with the underlying periosteum. Thus, minimal inflammation or instrumentation of the bony canal causes significant pain and/or