|Year : 2012 | Volume
| Issue : 2 | Page : 62-64
The value of TORCH screening in children with bilateral profound sensorineural hearing loss
Rabee M Al Sabellha, Abdulrhman Hager
Department of Otologyneurootology, King Saud University, Riyadh, Saudi Arabia
|Date of Web Publication||6-Sep-2012|
Rabee M Al Sabellha
Department of Otologyneurootology, King Saud University, Riyadh
Source of Support: None, Conflict of Interest: None
We aimed to ascertain the effectiveness of TORCH (toxoplasma, rubella, cytomegalovirus, herpes simplex) investigation in children with profound sensorineural hearing loss (SNHL). Review of TORCH laboratory results in 2011 from 168 patients who had cochlear implants between 2006 and 2010 at King Abdul-Aziz University hospital Riyadh was conducted. Of the 168 patients, 102 had TORCH laboratory results. Nine were positive for cytomegalovirus (CMV) IgM antibody (8.8%), two were positive for herpes simplex virus (HSV) IgM antibody (1.96%), and one was positive for rubella IgG (0.9%). No patient showed positive results for toxoplasma or syphilis. The mean age at which the request was made was 5.89 years. All 102 patients who had TORCH laboratory results were above the age of 2 years, and all the patients had bilateral profound SNHL. The nine patients who were positive for CMV were above 1 year old, and it was thus difficult to differentiate between congenital and acquired CMV infection; however, acquired CMV is unlikely to cause a neurodevelopmental disability.
Keywords: Cochlear implant, Congenital sensorineural hearing loss, TORCH
|How to cite this article:|
Al Sabellha RM, Hager A. The value of TORCH screening in children with bilateral profound sensorineural hearing loss. Indian J Otol 2012;18:62-4
| Introduction|| |
The acronym TORCH (toxoplasma, rubella, cytomegalovirus, herpes simplex) was introduced in 1971 by Nahmis et al.  A TORCH screen can give the false impression that all congenital infections can be diagnosed with a single serum sample. Although this may be sufficient to diagnose congenital rubella and maternal toxoplasmosis, other samples are usually required to diagnose the other infections. Because the presence of maternal antibodies will complicate the interpretation of specific IgG results, and IgM specific for Toxoplasma gondii and cytomegalovirus (CMV) may be detected in only about half of all congenitally infected neonates, serological results must be interpreted with caution. Kits for TORCH testing using serological methods should therefore be used with care.
Congenital CMV is best diagnosed in the first 3 weeks of life by detection of the virus in urine using culture methods, immunofluorescence, or electron microscopy, as infants with congenital CMV excrete high titers of virus but may have no detec IgM specific for CMV. Neonatal herpes may be diagnosed similarly, but the features of neonatal herpes may not develop for 10-14 days after birth, and about a fifth of infected babies have no skin lesions. The poor diagnostic yield of a single serum sample to diagnose such an assemblage of clinical entities is thus apparent, and the presence of any pathogen-specific IgM should warrant additional confirmatory testing.
The potential for development of sensorineural hearing loss (SNHL) or developmental disability is a particularly important result of infection. Failure to identify infants who may benefit from early intervention programs or hearing aids could delay the institution of useful interventions.
CMV is a leading cause of congenital infections and long-term neurodevelopmental disabilities in children. The incidence of congenital CMV infection is approximately 1% among infants born in the United States;  infection is detected by polymerase chain reaction (PCR) amplification of CMV DNA in urine, blood, saliva, and cerebrospinal fluid (CSF), or by the detection of CMV IgM antibodies in blood before 3 weeks of age.
When long-term sequelae become evident in previously asymptomatic infants, it is possible to make a retrospective diagnosis of congenital CMV infection by testing for the presence of CMV DNA in dried blood spot samples collected and stored from the neonatal screening period.
The diagnosis of congenital CMV infection is difficult to establish after the first year of life because normal infants can become infected asymptomatically, shed virus in their urine, and show increased antibody titers. Fortunately, it is unusual for CMV infection acquired after birth to cause SNHL.
The incidence of congenital rubella syndrome in developing countries has been reported to be 0.6-2.2 per 1000 live births.
The risk of vertical transmission from a non-immune mother with primary rubella infection in the first trimester of pregnancy is very high at 80-90%. Beyond the first 12 weeks of gestation, fetal organogenesis is nearly complete, and deafness may be the only consequence in the infected infant. Laboratory testing is useful in diagnosing congenital rubella infections; tests include the isolation of rubella virus from the urine of an infant during the first few weeks of life, isolation of the rubella virus from throat cultures, and documentation of increasing anti-rubella antibody titers during the first few months after birth. Alternatively, a diagnosis can be made by detecting rubella-specific IgM in serum or oral fluid taken before 3 months of age, or by demonstrating persistent rubella IgG in serum taken between 6 and 12 months of age. Additionally, detection of rubella virus by PCR of samples from nasopharyngeal swabs, urine, CSF, and blood can also confirm infection up to the age of 1 year.
Toxoplasma gondii is a ubiquitous protozoan with a worldwide distribution. Infection with T. gondii is acquired through meat and meat products, from the environment through poor hygiene, and via contaminated surface water. Although human infection is usually asymptomatic and mild, fetal infection can result in serious disease. Most infants with congenital toxoplasmosis are asymptomatic initially, although 80-90% may develop eye and neurological diseases later in life. In infants, the presence of T. gondii-specific IgM or the persistence of IgG beyond 12 months of age is suggestive of congenital infection.
Herpes simplex virus
Neonatal herpes infection is a potentially devastating consequence of the common genital infection caused by human herpes simplex virus (HSV). Although previous reports have implicated HSV-2 as the primary cause of neonatal herpes, recent studies indicate that HSV-1 also plays a major role in causation. Primary maternal infection results in a higher incidence of neonatal herpes compared to reactivation disease in the mother. Intrauterine HSV infection during early pregnancy is rare; most neonatal HSV infections are perinatally acquired via contact with infected lesions in the maternal genital tract. HSV DNA can be detected in the CSF by PCR, but although useful for diagnosing CNS and disseminated disease, it is present only in 70% of the cases. Serology has little value in the diagnosis of neonatal HSV infection due to high cross-reactivity between HSV-1 and HSV-2 and the late appearance of IgM antibodies.
The causative organism of congenital syphilis, Treponema pallidum, can be transferred across the placenta and infects the developing fetus as early as 6 weeks of gestation. The risk of vertical transmission and infection in the newborn is directly related to the stage of maternal syphilis during pregnancy; transmission occurs more frequently during primary or secondary syphilis in the mother than during latent disease. Direct identification of T. pallidum with dark-field microscopy or direct fluorescent antibody testing of neonatal skin lesions, placenta, or the umbilical cord can help in the definitive diagnosis of congenital syphilis. Serological testing remains the mainstay of diagnosis. Non-treponemal antibody tests such as the Venereal Disease Research Laboratory (VDRL) test or Rapid Plasma Antigen (RPR) test are excellent screening tools as they are sensitive, relatively rapid, and inexpensive. Specific treponemal antibody tests, including the microhemagglutination test for T. pallidum (MHA-TP) and the fluorescent treponemal antibody absorption (FTA-ABS) test, are highly specific and can be used to confirm a diagnosis.
| Discussion|| |
In our study, all patients with SNHL who were positive for infections assessed by TORCH were older than 2 years and none had had confirmatory tests. TORCH is used mainly for screening pregnant women and infants who are small for gestational age (SGA) or who have microcephaly, unusual exanthemata, organomegaly, or thrombocytopenia. Children with established bilateral profound SNHL will not benefit from TORCH investigations since there is currently no treatment that can reverse the profound hearing loss. However, if the screening had been performed early on, early management could prevent progression and stabilize hearing.
In Dublin, Cullen et al. reviewed laboratory results from TORCH screening from 1991 to 1995 and documented nine cases of CMV in a 5-year period, six of which had already been suspected.  TORCH screening in Ireland has an unacceptably low yield, and in the opinion of the authors should be abolished. Shet et al. noted that infections acquired in utero or in the immediate post-natal period play a prominent role in perinatal and childhood morbidity, and that TORCH screening is popular among perinatologists and pediatricians even though its limitations are becoming increasingly clear. They comment that a number of new organisms responsible for congenital and perinatal infections have been identified, along with diagnostic tests to confirm infections in infants, and that the diagnostic yield of the TORCH serological panel is low.  Their opinion is echoed by Holtmon et al., who evaluated the use of TORCH by pediatricians and pediatric trainees in a university pediatric department. They reexamined patient charts from 109 samples submitted to the Institute of Bacteriology from 1987 to 1991 for evidence suggestive of congenital infection, but found that the charts contained little information that could justify the ordering of a full TORCH panel. None of the submitted samples yielded conclusive evidence of congenital infection, and TORCH studies appeared to have been requested on very liberal indications. 
We conclude that the TORCH panel as used at present involves a lot of work for microbiologists, but yields little information. A more targeted approach to test for congenital infection seems to be necessary. Early diagnosis of neonatal infections is important, along with an effective therapy for such an infection. In a phase II trial, Whitley et al. reported hearing improvement or stabilization in 16% of 30 infants with symptomatic congenital CMV infection following ganciclovir therapy. 
| Conclusion|| |
TORCH investigations in children with profound SNHL, aged older than 1 year, were not useful in the management of patients and were expensive. The current review indicates the importance of establishing an early diagnosis with an automated otoacoustic emissions (AOAE) program and also by auditory brainstem response (ABR) and offers early intervention and management.
| References|| |
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