EAR INFECTIONS AND HEARING LOSS

Otitis media refers to inflammation of the middle ear. When an abrupt infection occurs, the condition is called “acute otitis media”. This condition occurs when a cold, allergy, virus, or the presence of bacteria leads to the accumulation of pus and mucus behind the eardrum, thus blocking the eustachian tube. This can cause earache and fever.

When fluid sits in the middle ear for weeks, the condition is known as “otitis media with effusion.” This condition occurs in a recovering ear infection. Fluid can remain in the ear for weeks to many months. If not treated, chronic ear infections have potentially serious consequences, such as temporary hearing loss.

To understand earaches and ear infections, you must first know about the eustachian tube. The eustachian tube is a narrow channel connecting the inside of the ear to the back of the throat, just above the soft palate and uvula. The tube allows drainage of fluid from the middle ear, preventing fluid from building up and bursting the thin ear drum. In a healthy ear, the fluid drains down the tube, assisted by tiny hair cells, and is swallowed.

The tube also maintains middle ear pressure equal to the air outside of the ear, enabling free eardrum movement. Most of the time, the tube is collapsed in order to prevent germs residing in the nose and mouth from entering the middle ear. Infection occurs when the eustachian tube fails to do its job. When the tube becomes partially blocked, fluid accumulates in the middle ear, trapping already present bacteria which then multiply.

Children have Eustachian tubes that are shorter, more horizontal, and straighter than those of adults. These factors make the journey for the bacteria quick and relatively easy. They also make it harder for the ears to clear the fluid since it cannot drain with the help of gravity. A child’s tube is also floppier, with a smaller opening that easily clogs.

Most people with a middle ear infection or fluid have some degree of hearing loss. The average hearing loss in ears with fluid is 24 decibels, equivalent to wearing ear plugs (twenty-four decibels is about the level of the very softest of whispers). Thicker fluid can cause a more severe loss of up to 45 decibels (the range of conversational speech).

You should suspect hearing loss if one is unable to understand certain words and speaks louder than normal.

Conductive hearing loss is a form of hearing impairment where the transmission of sound from the environment to the inner ear is impaired, usually from an abnormality of the external auditory canal or middle ear. This form of hearing loss can be temporary or permanent. Untreated chronic ear infections can lead to conductive hearing loss. If fluid is filling the middle ear, hearing loss can be treated by draining the middle ear and inserting a tympanostomy tube.

Sensorineural hearing loss is the other form of loss. This type of hearing loss is due to abnormalities of the inner ear or the auditory division of the 8th cranial nerve. Historically, this condition can occur at all ages and is usually permanent.

A hearing test should be performed for children who have frequent ear infections, hearing loss that lasts more than six weeks, or fluid in the middle ear for more than three months. There are a wide range of medical devices now available to test a child’s hearing, eustachian tube function, and flexibility of the ear drum. These devices include the otoscopy, tympanometer, and audiometer.

Children and adults can incur temporary hearing loss for other reasons than chronic middle ear infection and eustachian tube dysfunction. Reasons for hearing loss include:

• Cerumen impaction (compressed earwax).
• Otitis externa: Inflammation of the external auditory canal, also called “swimmer’s ear”.
• Cholesteatoma: A mass of horn shaped squamous cell epithelium and cholesterol in the middle ear usually resulting from chronic otitis media.
• Otosclerosis: This is a disease of the otic capsule (bony labyrinth) in the ear. The condition is prevalent primarily in adults and characterized by the formation of soft vascular bone leading to progressive conductive hearing loss. It occurs due to fixation of the stapes (bones in the ear). Sensorineural hearing loss may result because of involvement of the cochlear duct.