Sensorineural Hearing Loss As A Result Of Congenital Cytomegalovirus Infection
Hearing loss is very common abnormality in newborns at birth. If the newborn hearing ability is compromised, it can hinder speech and language growth. This essay will discuss the link between cytomegalovirus infection and late onset hearing loss faced by young molly. According to Victorian Deaf Education institute, the incidence of newborns having a sensorineural hearing loss is 1 to 2 newborns per 1000 live births. This frequency further increases to 3.2 per 1000 newborns. The hearing loss can occur as a result of genetic or non-genetic problems. If the hearing loss is genetic there is 30% chance that it is syndromic and 70% chance that it is non-syndromic. Conversely, if the hearing loss is not genetic, it could be due to congenital infections or perinatal conditions such as the baby being born premature or have infections such as jaundice. In all Australian states and territories, universal newborn hearing screening is being implemented. Molly has undergone the same process. This hearing screening began in 2002 and has a target rate of 97% newborns. The hearing test is conducted in the hospital itself when the baby is born or within few days after birth. The test is commonly performed when the baby is asleep or settled. The hearing screening usually includes otoacoustic emission testing (OAE’s) and automated auditory brainstem responses (AABR). However, the newborn hearing screening can include OAE only or AABR only but there are also times when it uses both the technologies together. For instance, in the western Australia newborn hearing-screening program, OAE’s are conducted first and if a ‘pass’ is not achieved then the audiologists move onto doing AABR testing.
All states in Australia have different protocols regarding newborn hearing screening. Different trained professionals carry out the testing at different locations and at various times after the baby is born. In victoria, the infant hearing screening is carried out within the first few weeks of life when the baby is in the hospital itself. If a pass result is not obtained then the newborn is referred to the audiologist for a full diagnostic. OAE’s can measure the auto acoustic energy produced by the inner ear in response to clicks. These clicks are delivered via a probe tip inserted in the ear canal. The results are displayed on the screen. If the results fall under certain norms it is a pass otherwise the newborn is referred for a full diagnostic checkup.
On the other hand, the AABR measures the inner ear along with the integrity of the auditory pathway. This test is able to detect for any risks a newborn might be having for auditory neuropathy. It is a non-invasive test in which the baby’s ears are covered with ear couplers that allow the clicking sound to be transmitted through. Along with that, three electrodes are placed on the neck, shoulder and forehead. This allows the auditory nerve’s activity to be measured while the sound is playing. The baby has to do nothing and the results are automatically displayed. When Molly had her newborn screening, she passed these tests and all her results were normal. When molly was born her mother was infected with Cytomegalovirus (CMV). However, molly didn’t show any signs or symptoms of being infected by the virus. As a result, she had developed congenital cytomegalovirus infection. In molly’s case she was asymptomatic at birth therefore, when all the newborn hearing screening was carried out we were unaware that she was suffering from the condition. About 90-95% of infants suffering from congenital cytomegalovirus show no symptoms at birth or even few days later until they are in the hospital or the nursery, says Dr. Fowler from the University of Alabama.
The condition can also be symptomatic which can be taken care of. However, molly’s condition didn’t show any apparent disease at birth so her condition went unnoticed. Molly developing a sensorineural hearing loss was as a result of this congenital CMV infection. This hearing loss is the most common sequelae following a congenital CMV infection. The severity of the hearing loss is variable and can range up to profound bilateral hearing loss. About 33-50% of sensorineural hearing loss due to the congenital cytomegalovirus infection has a later onset. Molly also had a late onset hearing loss due to her condition. The progression of this loss is inconstant so CMV infected children should have their audiologic testing done every 3-6 months. Cytomegalovirus virus belongs to a group of herpres virus family. This family also includes herpes simplex virus and other viruses causing chickenpox and mononucleosis. Once the person is infected, the CMV virus can be alive in one person’s body for the whole life but in a dormant phase. The virus infected Molly’s mother while she was pregnant with molly. Therefore, the unborn molly was also infected. This is why it was called a congenital CMV infection. This infection can be reduced in a number of ways. The mother should be washing her hands thoroughly with soap and dry them well. This should be done after being in contact with children, handling their toys and changing nappies or even feeding them.
Another recommendation involves not sharing food, drinks or dishes with children. Contact with saliva while kissing a child should also be avoided to prevent the risk of developing this condition. Congenital cytomegalovirus presents as a sequeale and includes signs of hearing loss that could be either progressive or late onset. Other symptoms include loss of sight, disability in life, and the head being a smaller size than normal, seizures and also coordination is impaired. In regards to molly’s condition no overt symptoms were observed. There is evidence that its signs and symptoms are not always obvious.
Antiviral medications such as valganciclovir can be of some help to children suffering from CMV virus. This can somewhat help in the improvement of development and hearing. Molly was detected as having a congenital infection later after birth, she should therefore be tested subsequently for a hearing checkup as this hearing loss can be progressive in nature as she grows old. Molly’s speech and language development was delayed due to her sensorineural hearing loss that was detected at 2.5 years of age. By this time she should have followed the developmental milestones chart and reached a certain level. The hearing loss would have impeded her normal development. According to the national institute on deafness and other communication disorders, within 1-2 years molly should have been able to follow simple instructions and act upon them. She should be able to understand simple stories. She should also be able to start communicating with either one or two words. Between 2-3 years she should know the maximum amount of words and should be able to put two or three words in context. Furthermore, she should be able to identify her toys and also be able to talk to her family members in a way that they can understand what she is asking.
Molly’s parents were concerned as she was unable to develop all these speech and language skills. A normal child without any hearing loss has optimum speech and language development according to the checklist of developmental milestones described. In regards to Molly being unable to reach optimum growth and developmental milestones we need to find a solution. An improvement in her speech and language development is highly recommended after the detection of her moderate to severe sensorineural hearing loss. She can be referred to Australian hearing for the discussion of amplification options that could be helpful. We need to counsel the parents that these amplification options are not going to correct the hearing loss however will be a great help when molly enters school. It will not delay her ability to develop normal speech and language development. We can also educate them regarding the different styles of hearing aids available so they can choose to the best of their ability. We can assess their needs and accordingly modify the hearing aid to achieve the best results. Molly can also be provided with assistive listening devices for the purposes of her kindergarten or schooling. Additionally, we can assess the financial aspects and ask the parents as to what they want for molly in terms of her having the least compromise in her growing age.
Cochlear implants can also be considered if the hearing aid is not providing effective amplification. The congenital CMV infection present in molly should be kept in mind when her parents are planning another baby in future. The virus remains in the body throughout life so can be reactivated. They would not want to have another child who develops a hearing loss like molly. This infection can be diagnosed by testing a newborn’s urine, blood or saliva. These can be collected within 2-3 weeks after birth to effectively diagnose the congenital CMV infection.
Molly should have been tested for CMV infection in the first few weeks itself, as her asymptomatic condition can’t be detected after the newborn period. Effective management can be an option for molly however research is still on in further understanding the CMV related hearing loss. Along with that interventions for the reduction of sensnorinueral hearing loss due to congenital CMV infection are still being looked at.
