Hearing loss is one of the most common disabilities around the globe. Affecting approximately 466 million people worldwide, or more than five percent of the global population, the loss of hearing has become one of the most frequent reasons people visit their doctor.
While it’s more widely known that it can stem from aging, exposure to loud noises, traumatic injuries, and ototoxic drugs, it is not uncommon to be caused by viruses. In fact, according to Mount Sinai’s website, the majority of cases of sudden hearing loss can be attributed to viral infections.
There are two types of hearing loss caused by viruses, acquired and congenital as well as a combination of the two. Acquired hearing loss develops at some point after birth while congenital is present at birth. Combined hearing loss includes both conductive and sensorineural hearing loss.
Conductive Hearing Loss
Conductive hearing loss is usually caused by some type of barrier located in either the outer or middle ear. This can be the result of the way the ear is formed, earwax, the fluid within this area, or even tumors, though it’s not often caused by viruses. Barriers in these parts of the ear will obstruct sounds from reaching the inner ear. However, conductive hearing loss is often treatable with surgery or medications.
Sensorineural Hearing Loss
Recognized as the most common form of hearing loss, sensorineural hearing loss occurs when there is damage to nerves of the inner ear and hair cells. This type of hearing loss negatively affects the pathways leading from the inner ear to the brain. This type of damage is rarely correctable with either surgery or medication, but with the help of hearing aids, it can be effectively managed.
Sudden sensorineural hearing loss (SSNHL) and sensorineural hearing loss (SNHL) are both common results of contracting one of several viruses. SNHL is said to be responsible for about 90 percent of the hearing losses reported.
Mixed Hearing Loss
Mixed hearing loss is just that, a combination of both conductive and sensorineural hearing loss. It may stem from a problem affecting either the middle or outer ear as well as with either the inner ear or the auditory nerve. It can have a sudden onset or worsen over time and can affect one or both ears.
Viruses That Can Cause Hearing Loss
There are numerous nasty viruses that can affect the cochlea and blood vessels within the ear as well as other regions of the auditory system. Some are more common than others and certain areas of the globe are more likely to encounter them than others.
The viruses that can cause hearing loss may occur in childhood or later in life. While there is not a specific virus that is guaranteed to affect your hearing, there are several that have the potential. There is also no safeguard against avoiding the loss of hearing, though several of these viruses do have a vaccine that will give immunity to the disease.
Cytomegalovirus (CMV) is quite common. When this virus occurs in healthy people, there are often very few symptoms reported, but when it occurs in people with lowered immune systems or during pregnancy, it can cause major difficulties and even death.
Approximately 1 in every 200 babies are diagnosed with congenital CMV at birth and 1 in 5 will exhibit symptoms or be prone to long-term issues like hearing loss. This loss could be apparent when they’re born, or they may not show until later.
Human Immunodeficiency Virus (HIV) is a virus that depletes the immune system by attacking the T-cells designed to fight off infections. It’s spread through contact with specific body fluids from an infected person. Hearing loss is often a sideline complication in patients with HIV.
HSV is a virus that belongs in the family of herpesviruses, both type 1 and type 2. While it can affect both adults and children, babies born to mothers that are positive for either type can develop the virus in-utero. This can be prevented through medication or therapy as well as giving birth by cesarean.
Lymphocytic Choriomeningitis Virus (LCMV) is an RNA virus that can’t be transmitted from human to human. It can be transferred by coming in contact with urine, saliva, and rat feces. Not nearly as common in occurrence as with other viruses, it results in a congenital issue.
Measles/Mumps/Rubella (MMR) are all viruses from the same family. While most children in the U.S. are immunized with a series of shots starting in infancy, certain religions or countries don’t vaccinate against these three RNA viruses. In these cases, contracting any one of these could result in hearing loss. People who get the mumps virus can, with a correct diagnosis and swift treatment, have a shot at getting their hearing back, though permanent hearing loss is also a possibility.
Varicella Zoster Virus (VZV) is considered a DNA virus and belongs with in the same family as HSV. Causing problems with the auditory canal as well as the nerves located in the face and tongue, some cases of hearing loss associated with VZV can be stopped and hearing may even be restored through corticosteroids and the use of other medications. This virus is able to be reactivated and can result in either Zoster or shingles.
West Nile Virus is an RNA virus that is carried by insects such as mosquitoes. Both the dengue and yellow fevers are of the same family as West Nile. Hearing loss seldom is a side effect of this infection, and only in one of the cases where it did occur, the patient was unable to recover their hearing.
In the face of such adversarial viruses, we continue to create vaccines and antivirus protection to help slow these invisible thieves of sound. If you experience hearing loss in one or both of your ears, it’s important to seek treatment as soon as possible. The longer you wait, the worse the outcome could be. Contact your hearing health professional today.