|Year : 2012 | Volume
| Issue : 4 | Page : 193-195
Inner ear infections as cause of perinatal deafness
Vikas Gupta, Kapil Sikka, Rakesh Kumar, Ramesh C Deka
Department of Otorhinolaryngology and Head and Neck Surgery, All India Institute of Medical Sciences,New Delhi, India
|Date of Web Publication||19-Dec-2012|
Department of Otorhinolaryngology and Head and Neck Surgery, 4th floor, Room No 4057, Academic Block, AIIMS, Ansari Nagar, New Delhi
Source of Support: None, Conflict of Interest: None
Objective: To assess the role of infective agents as cause of sensorineural hearing loss (SNHL) in children. Setting: Tertiary care center actively involved in management of hearing impairment through cochlear implant program and other rehabilitation program. Materials and Methods: Retrospective chart review of 213 patients who underwent cochlear implantation at our center from 2007 to 2011 was carried out. Out of these, 185 were children. We have done the data analysis with regard to etiology of hearing loss in these 185 children. An etiology for SNHL could be established in 100 out of these 185 cases. Out of these 100 cases, we have further segregated cases where an infectious etiology was implicated. Results: Out of 185 prelingual cochlear implantees, etiology could be determined in 100 cases. Etiology was of infective origin in 26 of these 100 cases. Infective agents implicated in congenital acquired hearing loss were Toxoplasma, Rubella, Cytomegalovirus, and Herpes (TORCH) infections ( n = 9) including Rubella ( n = 7) and Cytomegalovirus (CMV) ( n = 2). Meningitis ( n = 11) and other infections ( n = 6) were responsible for secondary acquired hearing loss. Conclusions: Results showed that among the identified causes, infective agents were responsible in one-fourth cases of profound SNHL. Building awareness about such existence and their major role in causing SNHL among the otolaryngologists, pediatricians, obstetricians, physicians, audiologists and public is considered essential so that such preventable and controllable maladies are reduced by combined efforts from all these stakeholders.
Keywords: Congenital, Perinatal deafness, Sensorineural hearing loss
|How to cite this article:|
Gupta V, Sikka K, Kumar R, Deka RC. Inner ear infections as cause of perinatal deafness. Indian J Otol 2012;18:193-5
| Introduction|| |
Development of language, speech, and communication is one of the most gifted skills in humans. Achieving this skill is directly dependent on hearing function. Sensorineural hearing loss (SNHL) can thus cause extensive social, economic, and medical implications in patients based on the degree of hearing loss. Pathologies causing SNHL include hereditary, congenital, or acquired disorders in perinatal period or during infancy and childhood. ,,,
In developing countries, SNHL secondary to the infective diseases is a major public health problem. Various infective etiologies causing perinatal deafness include maternal Toxoplasma, Rubella, Cytomegalovirus, and Herpes (TORCH) infections, meningitis, mumps, measles, and others. Meningitis and other infections are either themselves responsible for SNHL or due to other factors like intensive care unit (ICU) care, ototoxic medication, electrolyte imbalance, etc., which might be associated with these conditions and diseases. ,,
SNHL secondary to these conditions is largely preventable and controllable. This can be achieved by implementing targeted immunization program, following recommended treatment protocols and above all, creating awareness among stakeholders. The pediatricians, the obstetricians, the physicians and the public must be made aware about possibility of developing SNHL in these situations and settings. 
| Materials and Methods|| |
A retrospective chart review and data analysis of the patients who underwent cochlear implants at our center from 2007 to 2011, was done. The data of 213 patients including 185 prelingual and 28 postlingually deaf implantees were available. The data of 185 prelingual cochlear implantees were carefully assessed and analyzed with regard to possible causes of hearing loss in this group of patients. Attempts are being made in this communication to bring important public health issues through these data.
| Data and Results|| |
While reviewing the data regarding the etiology of hearing loss in 185 prelingual cochlear implantees (2007-2011), we have observed that in about 46% (n0 = 85) of these cases etiology was unknown or could not be determined. Out of 100 cases in which etiology was determined, in 26 cases, hearing loss was of infective origin and thus possibly preventable. This constitutes 14% of the total cases (n = 185) and about one-fourth of the cases with known etiology ( n = 100 ). These were subdivided as follows:
Congenital acquired hearing loss
Nine of these cases were of congenital hearing loss due to maternal TORCH infections with a male to female ratio of 4:5 and an average age of 5.77 years (age range: 2-8 years). Out of these nine cases, seven cases were due to maternal Rubella infection and in two cases, Cytomegalovirus (CMV) was implicated. One of these nine cases also had birth asphyxia.
Secondary acquired hearing loss
A total of 17 cases developed hearing loss in infancy or in early childhood, which was either due to meningitis ( n = 11) or infections other than meningitis (n = 6).
Out of 11 cases of SNHL secondary to meningitis, 8 were male and 3 were female with an average age of 5.11 years (age range: 2-12 years); 2 of these 11 cases also had history suggestive of ototoxicity.
Six cases with male female ratio of 1:1 and average age of 5.56 years (age range: 2.5-12 years) were due to other viral or bacterial agents. These include measles, mumps, pneumonia, chicken pox, enteric fever, and labyrinthitis, possibly of bacterial origin.
The details of infective etiology are provided in [Table 1].
| Conclusions|| |
Availability of newer more effective vaccines and wider reach and implementation of immunization program have decreased the prevalence of many previously common nongenetic infective causes of SNHL, such as measles, mumps, rubella, and Haemophilus injuenzue type B meningitis. But, in India these still appear to be among the significant etiological factors for SNHL.
A decrease in incidence of acquired sensorineural hearing loss with a relative increase in genetic forms of hearing loss has been reported from developed countries, in past few decades. But same does not stand true for developing countries where acquired as well as genetic hearing loss still counts high. ,
This is contributed by poor socioeconomic status, lower health awareness, lesser institutional deliveries, inadequate neonatal care, poor literacy level, and high rate of consanguinous marriages. Incidence of congenital hearing loss is much higher in less developed or developing countries. ,,
TORCH agents are still an important cause of congenital SNHL in less developed countries. Pregnant women exposed to these agents carry a significantly increased risk of developing SNHL, visual, and other neurological defects in their offsprings.
After the introduction of rubella vaccine, the past few decades have seen a consistent decrease in congenital rubella incidence in developed countries. But, in developing countries, which lack a rubella vaccination program, congenital rubella syndrome remains a major cause of acquired congenital SNHL.  In our study rubella induced SNHL contributed 7% to the total cases with known etiology.
Only one-tenth of congenitally infected neonates have clinical signs of CMV infection at birth. Clinical signs include hepatosplenomegaly, jaundice, a petechial or purpuric rash, intrauterine growth retardation, or respiratory distress. ,
A total of 50% of the neonates with clinical signs of CMV infection at birth also have SNHL and there occurs a progressive increase in hearing thresholds in many of them. 
A total of 8-10% of neonates with silent CMV infection may later develop some degree of SNHL.  We found two (2%) cases of CMV infection as a cause of SNHL.
Bacterial or viral meningitis has a high incidence of permanent damage to the labyrinth, especially in the very young. Meningitis, as a cause of SNHL has dual implications. One, it causes deafness and two, it causes labyrinthine ossification that makes successful cochlear implantation difficult, and at times, impossible.
Haemophillus influenza type B and pneumococcus are the common pathogens causing meningitis. Hearing loss may occur during the early phase of meningitis but is mostly noted late. SNHL due to meniningitis may affect either one ear or both ears with bilateral loss being commoner and constitutes around 6% of all cases of SNHL in children. ,
Introduction of better antibiotics and better intensive care facilities has significantly reduced the mortality associated with meningitis and thus we see more postmeningitic subjects surviving with various morbidities including SNHL. 
Important predictors for bacterial-meningitis-associated hearing loss include: duration of symptoms longer than 2 days, absence of petechiae, glucose concentrations in cerebrospinal fluid of 0.6 mmol/L or lower, S pneumoniae as the cause, and ataxia. If presence of any one of these risk factors is used to identify children for hearing screening, no child with hearing loss will go undetected.  Although, a simpler strategy is to screen all children diagnosed with bacterial meningitis. 
Advocacy and implementation of newborn hearing screening has played a significant role in reducing the age of identification of hearing loss from few years to few months.  Our review of infective etiological factors therefore emphasizes the need of awareness among doctors and the patients to understand the pattern of the conditions and diseases, which cause such human maladies and deafness. The factors are still rampant in our scenario, and fortunately, still preventable. On the basis of our data and data published previously, ,, we suggest:
- Primary prevention of mumps, rubella, meningitis, measles, pneumonia through immunization. Wider coverage of these vaccine preventable infectious diseases would reduce the incidence of acquired SNHL in addition to prevention of serious infections.
- Emphasis should be laid on that more and more pregnancies should be registered and deliveries to be institutional. Health care personnels at these centers should be sensitized and trained to identify the deafness-related infections like TORCH.
- Physicians, pediatricians and intensivists should be guided through meetings, lectures; to be cautious while treating the child with meningitis. Use of steroids in the early part of the treatment should be considered.  Moreover, hearing tests should be done at the earliest possible, so that hearing loss if any should be recognized and managed.
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