Patients with ear infections may experience hearing loss as a complication. The hearing loss is usually one of two types: either conduction or sensorineural deafness.
Some amount of hearing loss may occur during an ear infection. This hearing loss might be partial to severe depending on the part of the ear affected and the extent to which the ear is affected. In most cases this deafness clears up along with the infection that is causing it but in some cases the disease might cause damage to some of the parts of the inner ear which could lead to a more prolonged or even permanent deafness. This article discusses the types of infections and disorders of the ear that can cause deafness and their symptoms.
The human ear is divided into three main areas; the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna, the auditory canal and the tympanic membrane or eardrum. The middle ear hosts the ossicles or the three bones, the malleus, incus and stapes, which are responsible for sound transmission, the round window, the oval window and the eustachian tube. While the inner ear is made up of the semicircular canals and the cochlea which is an organ that is shaped like the shell of a snail, which is responsible for converting sound waves into nerve impulses that can be transmitted to the brain. Each part of the ear has it’s own function in collecting and transmitting of sound to the brain so that we in effect can hear the sounds around us. Infection or inflammation to any part of the ear can obstruct hearing to some extent or the other.
What is Otitis Media?
When the middle ear is infected and inflamed, it is known as otitis media. When a sudden infection in the middle ear occurs, it is known as acute otitis media. When a bacteria or virus enters the ear, it often results in otitis media. Otitis media is an infection, and like other infections it causes a buildup of mucus and pus. An accumulation of mucus and pus behind the eardrum will obstruct the eustachian tube and cause ear pain and fever.
The bodies of young children are still developing, and the tubes in their ears are small and soft. So, children are at a higher risk for ear infections because their narrow eustachian tubes can easily be blocked. Children are also more prone to infections because their immune systems have not yet fully developed. Adults' Eustachian tubes are usually wider and better shaped to prevent against infection.
If the fluid in a patient's infected ear continues to persist for weeks, it is known as otitis media with effusion. This is often found in people who suffer from recurrent ear infections. If a person's ear infections are not treated properly, serious complications such as permanent hearing loss can arise.
How can Otitis Media Lead to Hearing Loss?
Buildup of fluid within the middle ear can reduce the sound absorption of the eardrum and therefore reduce a person's ability to hear. The average amount of hearing loss in fluid-filled ears is about 25 decibels. This amount of hearing loss is similar to hearing with earplugs in. In this type of situation a person might still be able to hear people talk at a normal volume but will not be able to pick up on whispers. Thicker fluids have an even greater loss of about 45 decibels, hearing loss of this level means that a person could have difficulty hearing even when spoken to at a normal volume, the individual might also speak in a louder voice because they are unaware of their own volume.
Types of Hearing Loss
There are two types of hearing loss: conduction deafness and sensorineural deafness.
- Conduction deafness: Conduction deafness describes an impairment in the ear's ability to transmit external sound waves to the inner ear. This is usually a result of an abnormality in the external or middle ear. When chronic or untreated ear infections are left untreated, conduction deafness can occur. The condition can be either temporary or, in the worst cases, permanent. If the deafness is a result of fluid buildup next to the eardrum, hearing will be restored once the fluid is drained. Fluid can be drained from the middle ear with a tympanostomy tube.
- Sensorineural deafness: Sensorineural deafness is when hearing loss is the result of a deformity in the inner ear or auditory branch of the vestibular cochlear cranial nerve. This type of deafness is usually permanent.
When Should I be Concerned?
You should visit a physician if you or your child has had recurrent ear infections. Loss of hearing that has lasted for more than six weeks and fluid in the middle ear for longer than three months are signs for concern. Doctors can easily test a patient's hearing with a variety of devices, so make an appointment.
Other Causes of Deafness
Several other conditions may be responsible for deafness in both adults and children. These include:
- Otosclerosis– This is a condition that affects the bony labyrinth of the ear, especially in the adults. Due to additional bone formation, progressive conduction deafness results. If the cochlear duct becomes involved, sensorineural deafness may also occur.
- Trauma– Trauma to the ear caused by a head injury can also result in hearing loss, temporary or permanent.
- Cholesteatoma– As a consequence of chronic otitis media, a mass of squamous cells and cholesterol that is shaped like a horn can appear in the middle ear. This can decrease a person's ability to hear.
- Otitis externa– Infection of the external ear can also lead to deafness. This condition is also called swimmer's ear and can be caused due to fluid buildup in the outer ear but might also have other causes
- Buildup of earwax - Excessive earwax in the outer ear could also lead to temporary deafness.
- Colds - Nasal congestion sometimes also causes fluid to build up in the middle ear making it hard to hear
Ear infections can definitely cause deafness but only in cases where they are left untreated and allowed to progress to a point where they damage the ear. Children or adults who show signs of a ear infection like ear pain, fever, itchiness in the ear, dizziness or imbalance, discharge from the ear, deafness or general irritability in infants with constant pulling of the ear should visit an ENT specialist at the earliest. With the right treatment, like a course in antibiotics and adequate care an infection can be cured thus preventing any further damage and chance of permanent deafness.