Doctor's Notes on Hearing Loss
There are two basic types of hearing loss, conductive and sensorineural. Conductive hearing losses result from physical problems with the movement of sound waves through the ear. An example is blockage of the ear canal that may be caused by wax build-up, blood, or a foreign body. Other types of conductive hearing loss may be caused by perforated eardrum or ear infections. Sensorineural causes of hearing loss are from damage to the hair cells or nerves that sense sound waves. Sensorineural hearing loss may be caused by trauma, medications, infections, and aging. Hearing loss may be unilateral (only 1 ear) or bilateral (both ears). The unilateral hearing loss is most often associated with conductive causes, trauma, and acoustic neuromas.
Hearing loss may be gradual or sudden, mild or severe. Hearing loss may be associated with other symptoms such as ringing in the ears (tinnitus), spinning sensation (vertigo), pain in the ear, and fever.
Hearing Loss Symptoms
Hearing loss may be gradual or sudden. Hearing loss may be very mild, resulting in minor difficulties with conversation, or as severe as complete deafness. The speed with which hearing loss occurs may give clues as to the cause.
- If hearing loss is sudden, it may be from trauma, acute inflammation, or a problem with blood circulation. A gradual onset is suggestive of other causes such as aging or a tumor.
- If you also have other associated neurological problems, such as tinnitus (ringing in the ears) or vertigo (spinning sensation), it may indicate a problem with the nerves in the ear or brain.
- Hearing loss may be unilateral (only 1 ear) or bilateral (both ears). The unilateral hearing loss is most often associated with conductive causes, trauma, and acoustic neuromas.
- Pain in the ear is associated with ear infections, trauma, and obstruction in the canal. Ear infections may also cause a fever.
Hearing Loss Causes
There are 2 basic types of hearing loss, which is called conductive and sensorineural.
- Conductive causes: Conductive hearing losses result from physical problems with the movement of the sound wave through the ear. A simple example is blockage of the ear canal.
- Obstructed external ear canal - Cerumen (wax) build-up, hematoma (blood collection), or foreign body in the ear canal. This is one of the most common causes of hearing loss and the easiest to fix.
- Perforated tympanic membrane - Caused by direct trauma such as a cotton swab, middle-ear infections (otitis media), or explosions (blast injury)
- Dislocated ossicle (malleus, incus, or stapes) - Usually from trauma to the ear
- Otitis media - Middle ear infection (probably the most common cause for conductive loss)
- Otitis externa - Infection of the ear canal that causes it to swell
- Retraction of the tympanic membrane (ear drum) toward the middle ear. This may be associated with a collection of skin called a cholesteatoma
- Sensorineural causes: Sensorineural causes are from damage to the hair cells or nerves that sense sound waves.
- Acoustic trauma - Prolonged exposure to loud noises causes the hair cells on the cochlea to become less sensitive.
- Barotrauma (pressure trauma) or ear squeeze - Usually in divers
- Head trauma - A fracture of the temporal bone can disrupt the nerves of the auditory system or the cochlea directly
- Ototoxic drugs - Certain drugs can affect hearing by damaging the nerves involved in hearing. Usually, this occurs when large or toxic doses are used but may also occur with lower doses.
- Antibiotics including aminoglycosides (gentamicin, vancomycin), erythromycins, and minocycline
- Diuretics including furosemide and ethacrynic acid
- Salicylates (aspirin) and nonsteroidal anti-inflammatories (NSAIDs) such as ibuprofen and naproxen
- Antineoplastics (cancer drugs)
- Vascular diseases (problems with blood vessels) include sickle cell disease, diabetes, leukemia, polycythemia, and diseases in which excessive blood clotting occurs.
- Children and adults with kidney problems are more susceptible to sensorineural hearing loss.
- Ménière disease - A disease that affects hearing and balance. It is usually associated with tinnitus (ringing in the ears). It has a gradual onset and may progress to deafness and severe vertigo. The cause is unknown but thought to be associated with fluid shifts in the inner ear.
- Acoustic neuroma - A tumor in the auditory nerve. Usually associated with ringing in the ears.
- Infections, include some occurring during pregnancy and soon after birth in neonates.
- Aging (presbycusis)
Sometimes it seems like kids are always getting ear infections. Ear infections are very common in children. Children get ear infections about two out of every three times they have a cold. Children are more prone to ear infections because their small ears do not drain fluid as well as adult ears. Kids’ immune systems are also immature, and this increases the likelihood of certain infections.
There are three types of ear infections. Each type is defined according to where they occur in the ear canal. An ear infection may take place in the inner, middle, or outer ear. Each type of ear infection may exhibit different symptoms.
Ear Infection : Test Your Medical IQ QuizQuestion
Ear infection or acute otitis media is an infection of the middle ear.See Answer
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.