aom=acute otitis media, asom=acute suppurative otitis media, om=otitis media
O Olubanjo. Epidemiology of Acute Suppurative Otitis media in Nigerian Children. The Internet Journal of Pediatrics and Neonatology. 2007 Volume 8 Number 1.
Otitis media is one of the most common childhood infections with most children presenting only when the ears begin to discharge. This study was aimed at determining the incidence of ASOM and factors associated with the disease. The prospective study was conducted at the Wesley Guild hospital , Ilesa over a one year period from 2004 to 2005. It included children aged 1 month to 14 years who visited the general paediatric outpatient clinic with discharging ears. Of the 10,303 children who visited the clinic, 104 subjects were included in the study giving an incidence of 1.01%. A higher proportion belonged to low social class, 75% lived in poorly ventilated and overcrowded houses with 97.1% exposed to indoor pollution . The mean age at introduction of other feeds was 5.103+/-1.94 and mean age at stoppage of breastfeeding was 16.68+/-2.87months.89% had unilateral disease while 93% had central perforation of the ear drum. Further studies will be required to confirm these associated factors as risk factors for the disease.
Otitis media is one of the most common childhood infections. It is the most common diagnosis made by otolaryngologists among children in Nigeria 1, yet its exact prevalence in many societies is not known2.Otitis media is known to be a spectrum of disease ranging from an acute non suppurative otitis media to chronic transformation of the disease which includes chronic suppurative and nonsuppurative diseases particularly when it is not treated or partially treated 2. Because of the wide range of presentation of the disease, most studies have been centered on the chronic nature of the disease in the tropics while there have been fewer studies on the acute nature of the discharging ears. In view of the dearth of studies on acute suppurative otitis media defined by the transient perforation of the tympanic membrane and formation of pus less than 6 weeks duration 3, this study was conducted with the aim of bridging the perceived gap in our knowledge base by looking at incidence of the disease and various epidemiological factors associated with it in our environment.
Patients and methodology
This study is a prospective study and hospital based carried out over a one year period in the general paediatric out-patient department of a hospital in the south west of Nigeria. The study population included children aged 1 month to 14 years who presented with discharging ears less than 6weeks duration. Children who presented with ear discharges limited to the external ears were excluded from the study. The history and otoscopic examination obtained from the subjects were documented on structured questionnaires. Ethical clearance was obtained from the hospital and consent was also obtained from parents of subjects.
Of the 10,303 children who visited the paediatric outpatient department over a one year period, 104 children met the inclusion criteria accounting for an incidence of 1.01%.
The prevalence of ASOM in this study was 1.01%, which is lower than the 2.4% reported by Ako-Nai 4 in a similar study conducted in a comprehensive health center. The difference may have been due to the higher denominator of patients using the health facility (Wesley Guild hospital Ilesa) where this study was conducted compared to that of Ako-Nai. This facility, which was initially a missionary hospital but now government owned delivers primary, secondary and tertiary level of care to the semi-urban populace of Ilesa and environ. Similarly the prevalence in this study is comparable to the community based study by Zakzouk who reported a prevalence of 1.05% amongst Saudi Arabian children in a nationwide survey 5.
OM is known to be a childhood disease with high incidence in the first 3 years of life 6.This is supported by the finding of a higher incidence in children below two years of age in this study. There was also a fall in the incidence of ASOM in the older aged children (table I).This findings is consistent with reports of other existing literature 7, 8 and supports the hypothesis that most adult who have otitis media must have had it when they were younger.
There was a slight female preponderance amongst children with ASOM with a male to female ratio of 0.9:1.The reason for this gender difference is not known. This finding agrees with the report of Amusa
The majority of subjects in this study fell into the low socio economic group (class IV) which agrees with other existing literature 1, 11.The socio economic classification used in this study was based on the model developed by Oyedeji 12 which uses educational qualification and occupation of both parents to assigned them to their social class. Poverty and poor medical seeking behavior may have contributed to the dominance of this socioeconomic group in the epidemiology of ASOM in the locality where this study was conducted. Paradoxically, fewer subjects fell into the social class V which is the lowest class. The reason may be due to extreme poverty and lack of education which characterizes this group thereby hindering them from seeking and utilizing orthodox care in hospitals in the urban area since the two subjects in this category were from surrounding villages.
Over 74% of the subjects in this study lived in overcrowded and poorly ventilated houses usually referred to as ‘face-to-face' in the community. These types of houses consist of many rooms housing many families with a central passage way in which they share same toilet, bathroom and kitchen. This type of housing which is usually overcrowded may contribute to the higher proportion of children with ASOM. Amusa in her work had reported significant association between overcrowding and Otitis media8 while Bruneau
Among subjects less than 24 month of age in this study, 71.1% were still breast feeding at the time of presentation and mean age at stopping breast feeding was 16.68+/-2.87 months with 87.1% denying the use of bottle feeding. It was also interesting that most of the children were exclusively breast fed for almost 6 months as recommended by world Health Organization (mean age at which other feed were introduced was 5.103+/-1.94 month).These findings tend to contrast with other existing literature who had reported a reduction in the incidence of OM in children who were breastfed 15, 16, 17and put to question the protective effect of breast milk as postulated by Newburg 17.
Unilateral disease with central perforation was more common compared to bilateral diseases and marginal perforation in this study. The reason for this difference is not clear. This agrees with other existing literature which had reported similar findings in chronics suppurative otitis media 6.
Other associated clinical features of ASOM in this study includes fever (46.2%), ear pain (38.5%), URTI(51.9%) and enlarged tonsils(35.6%).A slightly higher proportion of subject presented with signs and symptoms of URTI which agrees with other existing literatures who had reported that URTI increases the risk of OM. Ruuskanem reported a strong correlation between AOM and viral respiratory infections 18. Also, the proportion of subject with fever in this study cannot be explained solely by ASOM bearing in mind that this study was conducted in a region endemic for malaria for which some were treated. Amusa had reported incidence of AOM to be 29% amongst febrile children in the tropics 9.
In conclusion, higher proportion of subjects with ASOM practiced exclusive and prolonged breastfeeding as advocated by world Health Organization, belonged to the low socioeconomic class, lived in poorly ventilated and overcrowded houses and were exposed to indoor pollution. Further studies to confirm these factors as risk factors for the disease in this locality are advocated.
I will like to appreciate the contribution of my colleagues for their advice and contributions during the data collection of this study. My appreciation also goes to the nurses who ensured that the study ran smoothly.