Acute otitis media is infection of the middle ear and it is a very common problem in children. The majority of children will be diagnosed with at least one episode of otitis media.
The ear plays a key role in hearing. The ear is divided into the three part, the inner, middle and outer ear. The basic physiology of the ear involves sound waves hitting and vibrating the tympanic membrane. The tympanic membrane moves the three small bones of the middle ear the malleus, incus and stapes. The movement of the stapes causes the fluid in cochlea the vibrate. The cochlear cells will translate this vibratory information into nerve impulses and send it to the brain where sound is perceived.
The eustachian tube is the connection between the middle ear and the nasopharynx. The middle ear cleft is made up of the mastoid air cells posterior to the middle ear cavity, the eustachian tube and the nasopharynx. The middle ear cleft can be thought of as a miniature lung, these areas allow for ventilation and pressure equalisation and issues in these areas can thus result in middle ear pathology.
Acute otitis media mainly occurs in children and is a result of eustachian tube dysfunction. If the eustachian tube does not work otitis media can develop. For example infection or reaction in middle cleft can result in oedema of the eustachian tube, similarly adenoid hypertrophy from an infection can block eustachian tube drainage and pressure equalisation resulting in negative pressure in the middle ear.
Otitis media is more common in children precisely because of the anatomical difference of the eustachian tube between children and adults. Unlike adults eustachian tube, a childs’ Eustachian tube is more shorter, horizontally aligned, softer and has a smaller passageway. This allows for easier spread of infection from the nasopharynx to the middle ear.
The pathophysiology of otitis media follows a few stages.