Risk Factors for OM

Pathophysiology

Eustachian tube dysfunction is known to be the central theme of most OM pathogenesis. In young children, the tube is short and horizontal and this relatively widens and elongates as they age. So for children, when bacteria proliferate, it is able to colonize the tube, easily obstruct the area, and induce inflammation and infection. OM occurs as a consequence of this upper respiratory infection and further causes damage to the tube and nasopharyngeal mucosa.

Nasopharyngeal mucosa is altered by

• Modifying host immune function
• Inducing cytokine activity and inflammatory mediators
• Upregulating host cell surface antigens which serves as receptor sites for bacteria therefore increasing bacterial colonies and adherence

Eustachian tube dysfunction is due to

• Mucus properties are altered and mucociliary clearance is reduced by the mucosal cells lining the tube and nasopharynx
• Inconsistencies in the negative middle ear pressure, usually more severe for children < 24 months old
• Negative middle ear pressure promotes influx of virus and/or colonizing bacteria in the middle ear