CAUSES OF CHILDHOOD DEAFNESS
IN ILORIN, NIGERIA
*DUNMADE A.D. FMCORL, FWACS
*SEGUN BUSARI S. FWACS
*OLAJIDE T.G. FWACS
*OLOGE F.E. FMCORL, FWACS
*DEPARTMENT OF OTORHINOLARYNGOLOGY
UNIVERSITY OF ILORIN TEACHING HOSPITAL,
P.M.B. 1459, ILORIN, KWARA STATE,
NIGERIA.
ALL CORRESPONDENCE TO:
DR. A.D. DUNMADE
DEPARTMENT OF OTORHINOLARYNGOLOGY,
UNIVERSITY OF ILORIN,
P.M.B. 1515, ILORIN, KWARA STATE,
NIGERIA.
This paper was presented at the 12th Annual Scientific
Conference of Otorhinolaryngological Society of
Nigeria held in Abuja 2002.
1
SUMMARY
The very causes of deafness in children are still with us, despite global effort on
immunization against infectious diseases that cause the disability. Prevention of
deafness must be a priority to all the stake holders. It is the purpose of this study to
called attention to the major causes of deafness and thus to influence the practitioner
in his management of children with infectious diseases in order to prevent this hidden
handicap. To make him aware that prevention of preventable causes of deafness is by
far cost effective. The yet unborn or deaf potential babies could be helped by taken
more vigorous steps to prevent the causes. A retrospective study of 115 deaf children
seen over 3 year period between July 1999 to June 2002 in the ENT Department,
University of Ilorin Teaching hospital was done causes of their problem were
reviewed to meet the objective of this study. One hundred and fifteen children with
deafness was seen of which 40 (34.8%) are congenital, 75(65.2%) are acquired; of the
acquired causes Febrile illness (18.3%) measles (13.9%) meningitis (8.7%) mumps
(6.0%) and severe birth Asphyxia (4.3%) in that order are the leading five causes of
acquired deafness. There were 64 male and 51 female (M:F 2.5:2). The age range of
1-15 years was seen. The mean age is 6.7 years, 55.3% were seen at preschool age
under 6 years. This study hoped that physician would be reminded that prevention of
deafness is better by far.
Key words: Deafness, Childhood, and Prevention.
2
INTRODUCTION
The past two decades has witness a lot of research into the incidence and causes of
deafness. Deafness is a global problem. This hidden handicap through misconception
and superstition is regarded as a punishment by the gods or devil for the sins of the
parents, usually the mother6-7. No one can imagine the agony of a mother of a deaf
child in any part of the globe be it in the developed or developing country like
Nigeria, especially when he or she is the only child. Congenital deafness with mutism
is bad enough but acquired deafness especially when the child has developed fluent
speech then become deaf could be devastating on the mother when she sees her child
loosing the speech gradually. Problems of Nigerian children with profound deafness
were thought to be late diagnosis8. Although deafness is one of the greatest of all
disabilities, the hearings impaired are often a neglected group. They suffer from a
‘hidden handicapped’ that is commonly overlooked by health workers, communities
and government9. Deafness among the inhabitants of developing countries is gaining
recognition as a potential inhibitor of development. Just as Otho and ophthalmology
disabilities prevent people from realizing their potential and contributing fully to
society, so does the ‘hidden handicap’ of deafness. This study was carried out to
ascertain the causes of profound hearing loss in children between ages 1-15 years in
North Central Nigeria and to discuss the applicability of primary prevention in a
developing country where resources for secondary prevention or rehabilitation may be
extremely limited.
3
METHOD
The study was of 115 Nigerian children with history of hard hearing or to have
difficulty in hearing or inability to speak. Children referred from school for the deaf
of Ilorin for assessment of hearing before enrolment to school, form a bulk of the
study. A retrospective study between July 1999 to June 2002 in the ENT, Department
of the UITH Ilorin, Nigeria was carried out. Information was collected from
individual case notes, each hearing impaired child’s name, age, sex and questions
concerning possible or probable cause of deafness, likely age of onset of deafness
were carefully reviewed. Complete history was however difficult to obtain.
Conventional assessment techniques were used, patient with impacted wax and
middle ear disorders were treated. Any child with mild to moderate hearing loss was
excluded.
4
RESULT
The 115 children studied were 64(57.6%) male and 51(42.4) female M : F ratio of
2.5:2. The age and sex distribution of children with deafness is shown in Table 1.
The age range 1 to 15 years was seen the mean age is 6.7. years. 55.2% of the
children were seen at preschool age under 6 years. There is a negative correlation of
deafness with increasing age. The congenital causes of deafness were 40 (34.8%)
while acquired deafness accounted for 75 (65.2%). Out of the acquired causes, febrile
illness is the highest (18.3%) followed by measles (13.9%), meningitis (8.7%) mumps
(6.9%) severe birth asphyxia (4.3%) in that order are the leading 5 causes of acquired
deafness Table II. Febrile illness been the highest, the informant gives a history of
fever which after treating the child with antimalarials and analgesic, the child was
noticed to be losing hearing and speech. Other identified causes were Ototoxicity,
Neonatal Jaundice, Cerebral Palsy, Cerebral Malaria and congenital rubella syndrome.
One child had deafness in addition
Table I1 highlighted the causes of deafness seen in this study. There was no single
case of unilateral sensorineural hearing loss. All of them were bilateral. There were
other associated congenital problems like squint and Cataract in the child. The
mother confirmed that she had fever and rashes during pregnancy however, no
serological confirmation was done. The child was suspected to have congenital
rubella syndrome.
5
DISCUSSION
A male to female ratio of 2.5:2 was seen in this study, this was found to be similar to
3:2 found in other studies 1,2,3. Male preponderance may be sex linked related4 or male
are more valued in Africa setting. Thus the disease problems are reported early in
male children. Study by Holborow et al1 shows that 59% of deaf children were seen
before 6 years of age. In this series 55.2% of the patients are between ages of 1-6
years. Diagnosis is made mainly around this age because this is the enrolment year
for most children in school for the deaf, before six years a child is expected to be in
school no matter how delayed. About two-third of the causes of deafness in this
study, were acquired. measles, meningitis and rubella in that order were the three
major preventable diseases causing deafness according to the study done by
Christopher Holborow et al1 in a study of deafness in West Africa, in a similar study
in Ghana5, Measles, Convulsion and birth Asphyxia are the leading causes while in
Gambia9 it was found that Meningitis was a major identifiable disease causing
deafness. In this series it was found that febrile illness, Measles, meningitis, mumps
and severe birth asphyxia in order of frequency were the major causes of acquired
deafness. Measles accounted for 30% of sensorineural hearing loss in Ghana5 more
than a decade ago, and about 19.3% was recorded in a study done on Nigerian
children by Holborow at al1 (1982).
This study shows a significant reduced
percentage of 13.9% was due to measles. This might be a result of dividends of
global expanded programme on immunization.
Febrile illness.` fever’ causing
deafness need some clarification. About 18.3% was attributed to be causing deafness
in this series. The history from the parent or guardian is rather vaque and May be face
saving. Apart from the history of fever, the cause of hearing loss was not fully
established. The informant gives a history of brief febrile illness, which after treated
6
with antimalaria and analgesics; the child was noticed to be loosing hearing and
speech. No evidence of neck stiffness, convulsion, rashes or even administration of
their local Ototoxic drugs. Neck swelling was not noticed. The major history is just
fever. There is possible suggestion that malaria or antimalaria may be a significant
etiological factor in this case of febrile illness. The most frequent causes of fever in
Nigerian children is malaria fever. We belief that malaria may be associated with
hearing loss. This high percentage 18.3% in this series may be due to malaria.
Malaria has been implicated in the causation of deafness in several studies in the West
Africa sub-region1,3,10-12
Malaria fever causing deafness in children need to be
investigated, to find out whether effects of malaria and antimalaria drugs on children
run a seperate morbidity from adult. It is thought that malaria infection may cause
deafness either by local action with micro vascular changes in the end arteries of the
cochlear or in a general way by lowering resistance to disease and thus enhancing the
adverse effects of other infections. Meningitis and mumps account for 8.7% and
6.9% respectively of childhood deafness in this study. Meningitis causing deafness in
this zone, which geographically belongs to the “meningitis belt is about 8.7% it is
much less than measles 13.9% as measles viral infection affects a very young group
and younger age group than meningitis. Acute bacterial meningitis is one of the most
destructive acute infections. In the last fifty-years, a number of significant advances in
the management and prevention of the disease have lowered the case fatality rate to
roughly 10% percents13. Fifteen percent of patients who survive acute bacterial
meningitis developed Neurological sequelae. Permanent sensorinueral hearing loss
account for approximately 75% of these cases.
In many countries in Africa
Meningitis is one of the leading causes of deafness in children1,5,9,14. Ten out of the
115 children (8.9%) had meningitis. This figure is fairly comparable with that of
7
Brooby5 8.5% and that of Barton et al14 10%. There were no cases of unilateral
sensorineural hearing loss due to mumps. All eight out of 115 children who had
mumps have bilateral sensorineural hearing loss. Not that they do not exist, the child
might be able to manage socially, it will take the good observation of the teacher or
the parents of the child to detect this. Deafness following febrile convulsion is known
to occur in children11,12 none was found in this series. Association between sickle cell
disease and deafness has been widely documented but none was found in this study.
Congenial causes
About34.8% of the causes of deafness are congenital. Information about the true
causes of deafness is always difficult to obtain and retrospective history are more
difficult to interpret and in this respect this study is not different from others17,18. The
importance, however, is to attempt to identify major preventable causes of deafness in
children,
Only 1 child was suspected to have congenital Rubella (0.97%) there was positive
history of fever and rashes during pregnancy in addition there were associated other
congenital problem like Squint and cataract in the child, however, no serological
confirmation was done. Most parents would not open up to the positive history of
deafness in the family it is to avoid the social stigma. Neither of the parents would
admit to having deafness, blindness or psychiatric disease in the family tree.
Hereditary and familiar deafness may be difficult to ascertain, this is common in some
countries, a high percentages of familiar deafness reported from the Indian sub
continent and Ghana is almost certainly genetically determined due to the very
common custom of consanguineous marriage17-18. There were some with positive
history of maternal fever, warranting admission during the cause of the pregnancy.
The local antenatal concoction (locally called Agbo) is still relevant among the native
8
of low social economic group and concoction taken regularly with good intention
might have some Ototoxic if not teratogenic effects on the fetus.
PREVENTION
It is shown that ⅔ of the cases are preventable and this is where the emphasis of this
study lies. Early detection of deafness and early training are vital, more important by
far is the prevention of those diseased that cause deafness. The important of
immunization cannot be overstressed; immunization campaign against measles,
meningitis and mumps should be intensified to further reduce the incidence of the
disease. The yet unborn or the potential deaf can be helped in a great way if the
disease is prevented. Immunization Programme against meningococcal meningitis in
the Gambia has reduced the incidence of the disease9. Prevention of any disease is
not only better, but also by far cheaper than treatment19,20,22. Huge resources are
invested in the management of the deaf. Primary prevention can also be brought
about by good antenatal and prenatal care; information and public awareness should
be directed to some pre and perinatal causes considered avoidable; Awareness of the
danger of ototoxic drug and local herbs taken during pregnancy should be
emphasized.
Facilities and the medical services at the cottage hospital should be improved to
mitigate against the effect of severe birth Asphyxia and Kernicterus.
Secondary prevention that is those who are not totally deaf can be helped with the use
of hearing aids, Cochlear implant is not common in Nigeria and other developing
countries. Awareness about hearing aids is now on the increase in Nigeria but the
supply and the price is generally beyond the reach of those who need them. In
Nigeria the use of hearing aids by the deaf of negligible. The hot humid environment
9
is not favourable to electrical aids and batteries which deteriorate and repair could
only be done in few cities or sent abroad. We strongly believe it is still better to be
partially deaf than to be completely cut off in communication with the environment.
It is hoped that this study has drawn more attention to the causes of total
sensorineural hearing loss in children in Ilorin, Nigeria and thus would influence the
clinician in their management in order to prevent the preventable.
10
REFERENCES
(1)
Holborow C, Martianson, FD and Auger, N. A study of deafness in West Africa Int.
J. of Paeduar. Otorh, 1982; 4: 107-132.
(2)
Wright ADO, The Aetiology of childhood Deafness in Sierra Leonne.
SLMDA J. 6: 31-45.
(3)
Wright ADO and Leigh B. The impact of the expanded program on
humiliation on measles – Induced Sensorineural Hearing loss in the Western
Area of Sierra Leone. West African Journal of Medicine. 1995; 14; 205-209.
(4)
Sellers S, Beighton G, Horan F and Beighton PH Deafness in black Children in
South Africa, SA Med. J. 51 (1977) 309-312.
(5)
Brobby GW causes of congenital and acquired total Sensorineural Hearing
Loss in Ghanaian Children, Tropical Doctor1988; 18: 30-32.
(6)
Ijaduola GTA Ancient area and believes in Causation of deafness J of
Research in Ethno-Medicine 1986: 1; 22-25
(7)
Martinson FD Deafness in Africa proc. Xiith ORL world Congr. Budapest,
Hungary 1981: 519-523.
(8)
Ijaduola GTA. The problems of the profoundly Deaf Nigeria Child. Post graduate
Doctor-Africa, June 1983; 180 – 184.
(9)
B. McPherson and Holborow C. A study of deafness in West African the
Gambian Hearing Health Project International J. of Peadiar. Otorh. 1985; 10:
115-135.
(10)
Konatey – Ahuhu FD Pattern of Sickle Cell Diseases in Africa: A Study of
1550 Consecutive Patients. Thesis Presented to the University of London for
the Diploma of Doctor of Medicine 1971.
11
(11)
Bondi FS, The incidence and outcome of Neurological abnormalities in
childhood cerebral malaria. Trans Roy SOC Trop Med and Hug 1992:86:1719.
(12)
Chukwuezi AB Profound and total deafness in Owerri Nigeria East African
Med. J. 1991; 68:905-912.
(13)
Woodrow C.J and Brobby G.W Deafness and meaningitis in Africa. Postgraduate Doctor Africa 1989; 4; 89-93.
(14)
Barton ME, court SD, Walker W, causes of severe Deafness in School
Children in Northumberland and Durham. Br. Med. 1962; 1: 351-355.
(15)
Obiako MN Profound Childhood Deafness in Nigeria: A Three Year Survey.
Ear & Hearing 1987; 8: 74-77
(16)
Ijaduola GTA. The Principles of Management of Deafness.
Nig. Med.
Practitioner 1986; 12: 19-25
(17)
Kapur YP. Study of the Aetology and Pattern of Deafness in a School for the
Deaf in Madras. Proc. congr. World Fed. of Deaf Warsaw 1967.
(18)
David JB. Edoo BB, Mustafah, JFO and Hinch Cliffe RA. A Deaf Village
Sound, 1971; 5: 70-72.
(19)
Scely DR; Gloyd SS; Wright ADO, Norton SJ Hearing Loss Prevalence and Risk
Factors among Sierra Leonean Children. Arch Otolaryngol. 1995; 121: 853-858.
(20)
Wilson J. Deafness in Developing Countries: Approach to a Global Program of
Prevention Arch Otolaryngol. 1985:111: 2-9.
(21)
Matz G.J Aminoglycoside Coachlear Toxicity. Otolaryngology Clinic of North
America 1993; 26:(5): 705-712.
(22)
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12
TABLE I
Age & Sex Distribution
AGE (YR)
MALE
%
FEMALE
%
TOTAL
%
1 -3
15
14.1
18
17.6
33
31.7
4-6
16
15.3
10
8
26
23.5
7–9
16
15.3
9
7.1
25
22.4
10 – 12
9
7.1
9
7.1
18
14.2
13 - 15
8
5.8
5
2.4
13
8.2
TOTAL
64
57.6
51
42.4
115
100.0
13
Table II
Causes of Deafness in Children
NO. OF
CHILDREN
AFFECTED
40
34.8
Febrile Illness
21
18.3
Measles
16
13.9
Meningitis
10
8.7
Mumps
8
6.9
Severe Birth Asphyxia
5
4.3
Ototoxicity
4
3.5
Neonatal Functions
4
3.5
Cerebral Palsy
3
2.6
Cerebral Malaria
3
2.6
Congenital Rubella Syndrome
1
0.9
115
100
CAUSES OF DEAFNESS
Congenital
TOTAL
14
%