|Year : 2013 | Volume
| Issue : 2 | Page : 57-59
Pattern of congenital heart diseases among children with Down syndrome seen in Aminu Kano Teaching Hospital, Kano, Nigeria
Mustafa Asani, Ibrahim Aliyu, Umar Also
Department of Paediatrics, Paediatric Cardiology Unit, Aminu Kano Teaching Hospital, Kano, Nigeria
|Date of Web Publication||7-Dec-2013|
Department of Paediatrics, Paediatric Cardiology Unit, Aminu Kano Teaching Hospital, Kano
Source of Support: None, Conflict of Interest: None
Background: The association between Down syndrome (DS) and congenital heart disease (CHD) was first recognised by Garrod in 1894. Several studies have reported about 40-60% prevalence of CHD in DS and a predominance of left to right shunts like atrioventricular septal defects (AVSDs), ventricular septal defect, patent ductus arteriosus and atrial septal defect. Objectives: This study was carried out to find out the prevalence and types of CHD among children with DS. Materials and Methods: This was a retrospective study of the echocardiographic data collected over a 24-month period, between October 2009 and September 2011. The echocardiographic diagnosis of all children with DS referred was reviewed. Results: A total of 35 cases of DS were seen. The age ranged from 0.5-30 months. About 60% of the children with DS were aged 6 months and below. There were 19 males and 8 females giving a M: F ratio of about 2:1. A total of 77.1% of the children with DS had CHD. The most common CHD is AVSD (40%), followed by atrial septal defect (22.25%). A total of 22.25% had normal echocardiographic study. Conclusion: Early referral and screening of all babies born with the clinical phenotype of DS should be encouraged due to the high prevalence of CHD.
Keywords: Aminu Kano teaching hospital, congenital heart disease, down syndrome
|How to cite this article:|
Asani M, Aliyu I, Also U. Pattern of congenital heart diseases among children with Down syndrome seen in Aminu Kano Teaching Hospital, Kano, Nigeria. Niger J Basic Clin Sci 2013;10:57-9
|How to cite this URL:|
Asani M, Aliyu I, Also U. Pattern of congenital heart diseases among children with Down syndrome seen in Aminu Kano Teaching Hospital, Kano, Nigeria. Niger J Basic Clin Sci [serial online] 2013 [cited 2019 Sep 15];10:57-9. Available from: http://www.njbcs.net/text.asp?2013/10/2/57/122754
| Introduction|| |
Since the initial observations by John Langdon Down in 1866,  Down syndrome (DS) has provoked a lot of research interests. DS (trisomy 21) is the most common chromosomal abnormality seen in clinical practice.  The incidence of DS is estimated to be 1:800 live births. It is estimated that the true incidence may be twice as great if it is based on all concept uses because over 50% of trisomy 21 foetuses are spontaneously aborted.  DS has distinct clinical phenotype hence cytogenetic analysis are done primarily to identify the few cases that are due to translocation or mosaicism.  Apart from mental retardation and hypotonia, which are constant features, DS is associated with a lot of other malformations. Among these, cardiovascular abnormalities are of utmost interest because its clinical course has a large influence on the prognosis and survival of the patients.  The association between DS and congenital heart disease (CHD) was first recognised by Garrod in 1894.  Several studies have reported about 40-60% prevalence of CHDs ,, in DS. Several studies have reported a predominance of left to right shunts like atrioventricular septal defects (AVSDs), ventricular septal defect, patent ductus arteriosus and atrial septal defect. ,, This variation in incidence may be due to the multifactorial aetiology nature of CHD. To the authors' knowledge, the prevalence and types of CHDs among children with DS has not been reported in North-Western Nigeria.
| Materials and Methods|| |
This was a retrospective study of the echocardiographic data collected over a 24-month period, between October 2009 and September 2011. The echocardiographic diagnosis of all children with DS referred for echocardiography was reviewed. The echocardiography laboratory receives referrals from other hospitals and clinics in Kano as well as neighbouring states like Jigawa, Katsina, Yobe, etc., No cytogenetic analysis was done due to lack of facilities. The diagnosis of CHD was done using chest radiography, electrocardiography and echocardiography. Echocardiography was carried out using ALOKA cardiac ultrasound system, manufactured in October 2007. The machine has facility for M-Mode, 2D, Colour flow mapping and Doppler studies. All measurements were done using 5 MHZ sector transducer. Information obtained from the records included age, gender, clinical diagnosis and echocardiographic findings. Data was analysed for age, gender and types of CHD; results were illustrated by frequency tables and percentages.
| Results|| |
During this period, a total of 35 cases of DS were referred for echocardiographic study. The age ranged from 0.5-30 months with a median age of 6 months. About 60% of the children with DS were aged not more than 6 months, while only five (18.5%) cases were older than one year when they were referred for the echocardiographic study [Table 1].
There were 19 males and 8 females giving a M: F ratio of about 2:1. A total of 77.1% of the children with DS had CHDs. [Table 2] shows that the most common CHD among DS is AVSD (40%), followed by isolated atrial septal defect (22.25%). There was only a case of partial AVSD and the rest are complete types. There was only a case of sinus venosus ASD and the rest were secundum ASD.
Eight children (22.25%) had normal echocardiographic study. Other types of CHD were rarely seen as illustrated in [Table 2].
| Discussion|| |
In this study, infants accounted for about 85% of the subjects with DS sent for echocardiographic studies. The striking clinical phenotype of babies born with DS is a strong motive for health workers to seek early referral. In addition, it is a reflection of the common perception among attending physicians that CHDs are relatively common in DS.
Wren et al.,  concluded in their study that clinical examination alone is insufficient in detecting the presence of CHDs. Apart from the variability of clinical skills among physicians, only moderate to severe cardiovascular lesions are symptomatic hence early referral for echocardiograhic screening is desirable. In developed countries, pre-natal diagnosis of CHDs with the aid of foetal echocardiography is the key to early diagnosis and appropriate intervention because children with DS develop pulmonary vascular disease as early as 6 months of life.  For resource limited countries, it is recommended that all children with DS should have a cardiac evaluation at birth due to the high prevalence of CHD, which causes high mortality in the first year of life. 
The relatively high prevalence of CHD (77.1%) among children with DS in this study may be attributed to the relatively small sample size and to the fact that it is a hospital-based study. Most studies have reported a prevalence rate of 40-60% of CHDs among children with DS. ,, In this study, AVSD accounted for 40% of the CHD, making it the most common CHD found among the children with DS. Our finding is in agreement with other studies that found AVSD as the most common CHD among children with DS. ,, Another study in Lagos, Nigeria  found AVSD to be almost as common as the ventricular septal defect. AVSD is generally considered to be the most common CHD found among children with DS. Spicer  found AVSD in two-thirds of the DS children with CHD. Fewer studies have found other CHD to be the most common among children with DS. Otaigbe et al.,  in Port Harcourt, Nigeria found patent ductus arteriosus to be the most common CHD and Luciana et al. in Pelatus, Brazil found atrial septal defect to be the most common lesion. No reasons were given for these differences, probably due to the multifactorial aetiology of CHD. 
Multiple CHD lesions were seen in about 6% of the children in this study. Multiple lesions are not unusually seen in DS. Sang et al.,  described multiple lesions in 30% of the children, whereas Otaigbe et al.,  found out that as much as 61% of the children had multiple lesions. No explanation was given for this observation.
Hypertrophic cardiomyopathy was seen in a 6-month-old child in this study. It is rarely seen in DS.  Transient hypertrophic cardiomyopathy is believed to be caused by exposure to steroids and maternal diabetes.  These could not be confirmed to rule out in this child because he was lost to follow-up.
| Conclusion|| |
Early referral and screening of all babies born with the clinical phenotype of DS should be encouraged due to the high prevalence of congenital heart defects.
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[Table 1], [Table 2]