Meningitis and Hearing Loss
Hearing loss is caused by many factors, including advancing age, our genetics, trauma (one event or over time), fetal development, and infection. When a baby is born with hearing loss, or develops hearing loss during the first month of life, it may be due to an infection the mother suffered during pregnancy.
Certain infections can cause hearing loss at any age—and one of the most common culprits is bacterial meningitis. It is thought that over 30% of bacterial meningitis cases result in some degree of hearing loss-from mild impairment to profound deafness. In a 2006 study, the Gallaudet Research Institute reported that 3.2% of American youth with hearing loss had suffered meningitis, making the infection the second most common cause of hearing loss.
Source and Symptoms of Meningitis
As an infection in the lining and fluid around the brain and spinal column, meningitis advances rapidly. Its source may be bacterial, viral, fungal or parasitic. Viral meningitis occurs most often and causes fewer lasting consequences – such as hearing loss – than other forms of the disease. While meningitis can strike at any age, senior citizens and people under 20 years old are at the highest risk, and are most adversely affected. In most cases (except for viral meningitis), extremely powerful antibiotics are given to cure patients, and often, save their lives. However, just as meningitis can cause hearing loss, the very antibiotics used to cure it can cause hearing loss as well. Drugs that cause hearing impairment are described as ototoxic.
In cases of bacterial meningitis, steroids are also used to lessen neurological damage, and prevent long-term problems such as blindness and hearing loss. New treatments being tested include injecting steroids directly into the inner ear to improve hearing preservation.
The symptoms of meningitis can include:
Rapid onset of high fever
Sensitivity to light
Altered mental state
Beyond Hearing Loss Meningitis-related hearing loss can happen for two reasons: the death of nerve endings (hair cells) in the cochlea (auditory portion of the inner ear), which leads to mild-to-medium hearing loss; and physical damage to cochlea itself, which can lead to severe-to-profound hearing loss. Mild hearing loss can be remedied with hearing aids, while severe hearing loss may benefit from cochlear implants. In addition to hearing loss, balance problems and tinnitus can result from meningitis. Tinnitus is a ringing, buzzing or whooshing sound heard in the ears.
Some Good News about Meningitis–Related Hearing Loss
Quick treatment of meningitis can prevent or reverse hearing loss! Hearing loss is thought to occur during the first two days of the illness. If medication begins within this window, hearing loss can be stopped or helped. And, one interesting fact: a study in the British Medical Journal reported people with dark eyes are less likely to suffer meningitis-caused hearing loss than light-eyed people. A higher level of melanin is thought to be the reason.