About Viral Infections and Hearing Loss
Hearing loss after viral infection – also called sudden sensorineural hearing loss – is a perplexing problem that medical science has still not completely solved. A link between viral infection and sudden hearing loss has long been suspected, although the factors that lead to hearing loss after viral infection aren’t well-defined.
The hearing loss that occurs after viral infection is often sudden in onset, with many patients reporting that they awaken with hearing loss, or realize that they cannot hear when they try to use a telephone, listen to music, or perform another hearing-related task.
Alternatively, a patient may loss their hearing progressively over time. Either one or both ears may be affected, but bilateral hearing loss is relatively rare.
What Causes Hearing Loss after Viral Infection?
So what is the link between viral infections and hearing loss? For the most part, the evidence which links sudden hearing loss and viral infection is largely circumstantial.
While between 17% and 33% of people with sudden hearing loss report experiencing a recent viral infection, it is also important to note that in one study, 25% of patients visiting one otolaryngology clinic had experienced viral infection without hearing loss in the month prior to their visit (eMedicine).
However, ear examination of people who experience hearing loss after viral infection show ear damage in the cochlea which is consistent with injuries that occur as a result of viral infection. Structural changes which result in hearing loss (such as neuronal loss and atrophy of certain ear structures) have been noted in people who recently experienced mumps, rubella, measles, or herpes infections, among others.
The exact cause of hearing loss after viral infection is unknown, but studies show that during infections that affect the ears, the blood supply to the ears may be reduced, resulting in oxygen depletion and ear damage.
Is there a Cure for Hearing Loss after Viral Infection?
The hearing loss that occurs after viral infection is likely to be a result of oxygen depletion, explaining why it is not always possible to return normal hearing to a patient through treatment with medication - if the damage done is too severe, there may be no effective treatment.
Possible treatments include steroid medication to reduce damage caused by infection and inflammation, and antiviral agents in cases where infection is still active. Oxygen therapy to improve the supply of oxygen to damaged tissues can also be helpful in some cases.
For some people, hearing will return over time, as the damaged tissue repairs itself, but whether or not hearing returns is largely dependent on how much damage has been done. In cases where damage is severe, hearing loss may be permanent.
Fordice, J. (MD) Sudden Sensorineural Hearing Loss. Baylor College of Medicine.
Pitkaranta, A., Juha-Pekka, V., Julkunen, I. Sudden Deafness and Viral Infections. Otorhinolaryngol Nova 1999;9:190-197