The complicated organ known as the ear is composed of three sections – the inner ear, which contains the delicate organs of hearing; this being protected by the auricle or external ear, and the two connected by the auditory canal, the Eustachian tube; this latter terminating in the throat, just behind the tonsils. The function of the Eustachian tube is to allow air to enter the inner ear and permit vibration of the ear drum which separates the outer ear from the inner ear. Spread of infection from the nose and throat may therefore result in temporarily impaired hearing, which is due to blocking of the Eustachian tube, so that the drum cannot vibrate properly.
In more serious conditions, abscess formation may result if the infection spreads further into the inner ear.
The Eustachian tube is lined by mucous membrane which is continuous with and of the same nature as that lining the upper air passages. It is easy to see, therefore, how infection in the neighbourhood can spread along it. The result may be a sudden acute illness or a gradual chronic spread of inflammation from the nose and throat which will ultimately result in impaired hearing.
The first symptom is severe pain in the ear, which increases steadily while the patient becomes Feverish and restless. The pain is caused by the pus which forms in the middle ear as a result of rapid inflammation. The Eustachian tube is at the same time closed by swelling of its lining membrane, and the pus, being confined in a small space, causes acute pain by pressure. Deafness or roaring in the head are usually present.
The imprisoned pus may itself break through the ear drum and discharge through the external ear. It would seem that this might be satisfactory, and sometimes the inflammatory product being dispersed the eardrum heals up. But more often than not a path of infection having been opened up by this procedure, a chronic inflammation supervenes which manifests itself by a persistently discharging ear.
This condition if allowed to continue, will cause permanent injury to hearing and may also, by extension, threaten vital structures in the neighbourhood, such as the bones of the skull and the membranes of the brain.