Ear, disorders of

The ear is susceptible to various disorders, some of which can lead to deafness. In rare cases, the ear canal, ossicles in the middle ear, or pinna are absent or deformed at birth. Rubella in early pregnancy can damage the baby’s developing ear, leading to deafness. Most cases of congenital sensorineural deafness are genetic. Infection is the most common cause of ear disorders; it may occur in the ear canal, leading to otitis externa, or affect the middle ear, causing otitis media. This can lead to perforation of the eardrum (see eardrum, perforated). Persistent glue ear, often due to infection, is the most common cause of childhood hearing difficulties. Viral infection of the inner ear may cause labyrinthitis. Cauliflower ear is the result of one large or several small injuries to the pinna. Perforation of the eardrum can result from poking objects into the ear or loud noise. Prolonged exposure to loud noise can cause tinnitus and/or deafness. Pressure changes associated with flying or scuba diving can also cause minor damage (see barotrauma). Tumours of the ear are rare. Acoustic neuroma is a noncancerous tumour of the acoustic nerve that may press on structures in the ear to cause deafness, tinnitus, and problems with balance. In cholesteatoma, skin cells and debris collect in the middle ear. Obstruction of the ear canal is most often the result of earwax, although in small children, an object may have been pushed into the ear (see ear, foreign body in). In otosclerosis, a hereditary condition, a bone in the middle ear becomes fixed, causing deafness. Meniérè’s disease is an uncommon condition in which deafness, vertigo, and tinnitus result from the accumulation of fluid in the inner ear. Deafness in many elderly people is due to presbyacusis, in which hair cells in the cochlea deteriorate. Certain drugs, such as aminoglycoside drugs and some diuretic drugs, can damage ear function.