When you first find out that your child has a hearing loss, it is a natural reaction to ask, "Why?" It is believed that half of all hearing loss is due to genetic causes and the other half is non-genetic. Most people with a hearing loss, approximately 80%, do not know the cause of their hearing loss. At Adventist Pediatric Rehab, regardless of the cause, we have professionals who can help you and your child.
Family history of hearing loss (genetic hearing loss)
Genetic sensorineural hearing loss is divided into two general categories: non-syndromic, meaning hearing loss and nothing else, and syndromic, meaning hearing loss with other clinical findings, such as heart, kidney or skin abnormalities. By far, the more common is non-syndromic sensorineural hearing loss, which includes 2/3 of all genetic hearing losses.
There are numerous genes that are associated with sensorineural hearing loss. One gene, known as GJB2 is responsible for approximately 1/3 of all the cases of genetic sensorineural hearing loss. GJB2 is a gene that is necessary to produce a protein known as Connexin-26 (abbreviated CX26). CX26 is a protein necessary for the inner ear to develop. So, when there are abnormalities of the GJB2 gene, then CX26 is not produced, and the inner ear does develop properly. Children with CX26 abnormalities most commonly have a bilateral, severe-to-profound sensorineural hearing loss. Abnormalities of the GJB2 gene can be identified with a special blood test.
Congenital means that something occurred during pregnancy or at the time of birth. Sensorineural hearing loss may develop if a woman contracts certain types of infections during pregnancy or passes the infection to the child during birth. The types infections associated with pediatric sensorineural hearing loss include: toxoplasmosis, syphilis, rubella (German measles), cytomegalovirus (also known by the initials CMV) and herpes. The amount of hearing loss that can result varies widely and some babies show no hearing loss at all, even if they have one of these infections. Congenital CMV infection is the leading cause of acquired hearing loss in infants.
One illness that carries a high risk of causing hearing loss and/or balance problems is bacterial meningitis. Because meningitis is an infection of the lining of the brain and spinal cord, the sense organs of hearing and balance are especially sensitive to this infection. Pneumococcal meningitis is the most common cause of permanent, sensorineural hearing loss. Other causes of meningitis, such as E.Coli and group B streptococcal, are also causes of sensorineural hearing loss.
Sometimes medications that are known to be ototoxic (damaging to hearing) are prescribed to babies, usually to treat serious infections or birth complications. The most common ototoxic medications used at this time include a family of antibiotics called aminoglycosides with names such as gentamycin, tobramycin, kanamycin, and streptomycin. The aminoglycosides present more of a risk to hearing when they are used multiple times or in combination with other medications, such as diuretics.
Hyperbilirubinemia (jaundice) that is severe enough to require a blood transfusion can also result in sensorineural hearing loss. This is related to the potential damage that high levels of bilirubin can cause to the nerves of hearing and portions of the brain used for hearing.
Adventist Paulson Pediatric Rehab
222 E. Ogden Avenue
Hinsdale, IL 60521