Otitis media; acute

Alternative names:

acute ear infection; acute otitis media; infection of the inner ear; middle ear infection

Definition:

A disorder involving inflammation and/or infection of the structures of the middle ear.

Causes, incidence, and risk factors:

Inflammation of the ear (sterile otitis or serous otitis) may occur when there is a collection of sterile fluid in the ear. This may be caused by overproduction of fluid by the structures in the middle ear. It may also be caused by blockage of the eustachian tube (the connection between the middle ear and the back of the nose/upper throat). The presence of excess fluid causes the ear to become irritated and inflamed.

Acute otitis media (acute ear infection) occurs when there is bacterial or viral infection of the fluid of the middle ear, which causes production of fluid or pus. This may be accompanied by bleeding in the middle ear.

Pressure from fluids associated with ear infection may cause the eardrum to rupture. Conversely, a ruptured eardrum can result in ear infection by allowing bacteria or viruses direct entry to the middle ear. Ear infections are most common following respiratory infections, or if the sinuses or eustachian tube are blocked from allergies or enlarged adenoids.

Ear infections occur in approximately 3 out of every 100 people. They may affect anyone but are more common in children because their eustachian tubes are shorter, narrower, and more horizontal than in adults.

Risk factors include recent illness of any type (which lowers resistance of the body to infection), crowded or unsanitary living conditions, genetic factors (susceptibility of the ear to infection may run in families), high altitude, cold climate, and bottle feeding of infants allowing fluid to pool in the throat near the eustachian tube.