Why Do Some Viruses Cause Hearing Loss?
Why Do Some Viruses Cause Hearing Loss?
Viral infections can impact the auditory nerve, the blood vessels in the ear or other parts of the body that contribute to hearing well. Each virus has its own path of destruction. Some viruses lay dormant until the body is not able to ward it off any longer because of other health issues. A virus can cause increased susceptibility to bacterial or fungal infection, which may cause hearing loss. As with most viral damage to our bodies, note the use of the words “may” and “can” when reading about viruses.
What Kind of Hearing Loss Can Be Caused By a Virus?
The majority of viruses cause sensorineural hearing loss. This means that the hearing nerve or hearing organ are compromised. However, conductive and mixed hearing loss can also occur. This means that the mechanical pathway of hearing is compromised. These hearing losses can range from mild to profound and can be in both ears or only one. I have always found that unilateral hearing loss (hearing loss in one ear) from an invasion of a virus to be odd. You would think that if a virus gets into your system that affects hearing, it would damage both ears, but that is not the case.
Some hearing loss from viruses can be mitigated by antiviral therapy. We do not understand enough about the viral process to provide a definite outcome to a person suffering with a virus. There are so many variables, including an obvious one: how healthy the individual is. Is the body able to fight off the invasion and how successfully can it stay on top of it? Viruses are sneaky and may hang out for a bit before triggering the immune system.
Congenital Hearing Loss
There are viruses transmitted from a mother to her baby during pregnancy or during the birth process. The viruses known to cause congenital hearing loss are CMV, Rubella, HIV, HSV1 and HSV2. Many times, the newborn will have normal hearing but slowly acquire a hearing loss that will be evident around six to 12 months.
Rubella or German measles is thought to cause 32% of deafness. Rubella is a viral infection that causes a skin rash and joint pain that is usually mild in the person. However, it can be detrimental to an unborn baby if a pregnant woman contracts this virus. Rubella causes direct damage to the hearing organ (cochlea) in an unborn baby. There is a vaccination for Rubella with 97% effectiveness at preventing the virus. I have seen many children with hearing loss from Rubella. When I first started practicing audiology, I saw more cases, but now because of the increased use of the vaccine, the numbers have been reduced significantly.
CMV (cytomegalovirus) causes inflammation in the cochlea in the unborn baby. This virus primarily hangs out in small children and goes home to the rest of the family members, including a pregnant mom. There is no vaccine for this virus.
The Use of Vaccines in the Mitigation of Diseases
I have seen first-hand the devastation caused by viral and bacterial diseases. Telling a parent that their beautiful child will have a permeant hearing loss is the most difficult part of my job. Discussing a sudden hearing loss secondary to a virus in a child or adult is extremely difficult. I documented a progressive hearing loss in a 5-year-old many years ago. We never figured out what was causing it and were helpless while we watched her lose her hearing.
There are vaccines for viruses such as Polio, measles and mumps, which used to infect more than 90% of susceptible children. The chicken pox and shingles virus caused by Varicella-Zoster is another cause for hearing loss in some people. Meningitis can be viral or bacterial; both strains are big culprits of hearing impairment and other permeant physical dysfunction. There are new vaccinations available for some of the meningitis variants.
I always recommend vaccinations to people on the fence about taking them. Scientifically, they are studied and documented to reduce or eliminate the targeted virus (have you seen a person with the physical deformities of Polio recently?). We have to keep up with the mutations, but that is a small price to pay for our health and lifestyle. FBN
By Karon Lynn, Au.D.
Trinity Hearing Center is located at 1330 N. Rim Dr., Suite B in Flagstaff. For more information, visit TrinityHearing.net.
Karon Lynn, Au.D., is a doctor of audiology with 30 years of experience working with hearing impaired individuals. She may be reached at 928-522-0500 or at audio@trinityhearing.net.
