Discharge from the ear is invariably due to an infection of the ear canal (otitis externa) or middle ear (acute or chronic otitis media). An offensive smelling discharge is more common with chronic infections, particularly due to gram negative bacteria.
Ear injuries are mainly due to a blow to the ear or head, or sudden extreme pressure changes. A blow to the auricle may cause a painful collection of blood under the skin (haematoma). Sudden pressure changes in the ear canal from a blow over the ear or poor syringing technique may rupture the ear drum and disrupt the ossicles. Landing in an aeroplane with Eustachian tube dysfunction and a middle ear effusion may cause severe pain and damage the ear drum. Blowing the nose hard or straining may raise the inner ear pressure and lead to the rupture of delicate membranes causing a perilymph fistula. A head injury with or without a skull fracture may also damage the middle and inner ear structures.
Ear itching is due to infection or irritation of the skin lining the external ear canal (otitis externa).
The most common cause of ear pain is infection either of the external canal (otitis externa, furunculosis) or middle ear (otitis media). The nerves which provide sensation to the mouth, nose and throat also supply the ear and the jaw (temporomandibular) joint. Pain may therefore also be referred from strain of the jaw joint with spasm of the adjacent chewing muscles, or conditions affecting other ENT sites.
Tinnitus is a symptom not a disease, which frequently accompanies hearing loss and can occur with almost every ear condition. Subjective tinnitus, which is by far the most common type, is only heard by the patient, whereas objective tinnitus can be heard by other people as well. The annoyance caused by the symptom is very variable and not directly related to the loudness.
Hyperacusis means increased sensitivity to sounds which therefore appear to be abnormally loud. The normal ear has a dampening mechanism to protect the cochlear hearing hair cells from damage due to excessive sound energy and to enhance their function. This mechanism is controlled by nerve fibres (cochlear efferents) which travel from the brain to the ear with one of the balance (vestibular) nerves. Increased sound sensitivity is a very frequent early symptom of inner ear disease.
There are two general types of hearing loss: Conductive hearing loss and Sensorineural hearing loss.
Conductive hearing loss is caused by any disruption in the passage of sound from the external ear via the middle ear to the oval window. Possible causes are impacted wax, tympanic membrane perforation, otitis media, middle ear effusion, ossicle problems including otosclerosis. Such hearing losses are often correctable with medical or surgical treatment.
Sensorineural hearing loss results from damage to the delicate hair cells of the cochlea or the nerve fibres of the auditory nerve. Presbyacusis, or hearing loss related to aging, and noise induced damage are the commonest causes. This type of hearing loss in one ear may be due to an underlying benign tumour (acoustic neuroma), Sensorineural hearing loss is generally permanent, though medical treatment of certain conditions can prevent further deterioration. When the hearing deficit exceeds 30% in both ears a hearing device (aid) is frequently a good solution. Occasionally a mixed hearing loss, that is part conductive and part sensorineural, may occur. Diagnostics
Pure tone audiometry, tympanometry and stapedial reflex tests will distinguish beween the different types of hearing loss and provide an indication of the level of disability. These tests will also enable the response to medical treatment to be measured or deterioration over time to be monitored. Otoacoustic emissions may be measured to screen the cochlea for early signs hair cell damage. When a patient has a sensorineural hearing loss in one ear, or which is worse in one ear, an MRI scan of the inner ear is essential to rule out a possible underlying acoustic neuroma.
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