Browsing by Author "De Decker, Rik"

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    Open Access
    An analysis of the phenotypic features of chromosomes 22q11.1 deletion syndrome at Red Cross War Memorial Children's Hospital
    (2018) Hendricks, Lesley Jill; De Decker, Rik
    Chromosome 22q11.2 deletion syndrome (22qDS) is an inherited autosomal dominant disorder. It is the second most commonly occurring syndrome, Trisomy 21 being the most common. It is the most common microdeletion syndrome. The clinical range of features with which affected individuals present is very broad and includes congenital heart disease (particularly conotruncal malformations), palatal abnormalities, characteristic facial features, and learning difficulties. In total, there are more than 180 different phenotypic features associated with 22qDS. Due to the wide variability of phenotypic features that can arise in 22qDS it is often difficult to know when to test for the syndrome. Oskarsdottir’s criteria are widely used in clinical recognition for 22qDS. However, in a study done previously at Red Cross War Memorial Children’s Hospital, this same criteria was found to only have a positive predictive value of 14% for 22qDS. This is likely due to the fact that Oskarsdottir’s study was based on a largely Caucasian study population. Our population in Southern Africa is largely non-Caucasian. Previous studies have confirmed that non-Caucasian population groups with 22qDS have different presenting phenotypic features. For this reason, in this study we sought to describe the typical phenotypic features with which children with 22qDS present in our local population in South Africa. A retrospective folder review was done of the phenotypic features of all patients who had had a FISH test done on the suspicion on 22qDS. A total of 144 patient folders were reviewed (72 patients who were FISH positive for 22qDS and 72 patients who were FISH negative and functioned as the control arm of this study). A review on the phenotypic features of children with 22qDS revealed the most common presentation to be congenital heart disease (44%), failure to thrive (33%), dysmorphic features (32%) and cardiac failure (25%). A positive family history was only noted in 13 patients. Of those patients with a positive family history of 22qDS, only 5% were proven FISH positive for 22qDS themselves (less than the 10% described in the literature). Younger children presented more frequently with CHD, while older children presented with developmental delay and dysmorphic features. In general, developmental delay, palatal abnormalities and feeding difficulties were less common in our study population than described in the literature. Our particular patient population presented with the following CHD: isolated VSD (46%), tetralogy of Fallot (20.8%), truncus arteriosus (14.5%), PS/pulmonary artery stenosis (20.8%) and interrupted aortic arch (6%). Interrupted aortic arch was found to be the most sensitive marker for 22qDS in children with cardiac lesions. The cardiac lesions with the highest positive predictive value for 22qDS was non-isolated VSD (54%). Dysmorphic features with the highest sensitivity for 22qDS included bulbous nose (75%), abnormal digits (64%) and posteriorly rotated ears (68%). Primary immune deficiency, thymus abnormalities, cleft palate and behavioural issues were described less in this study than previously described in the literature. In conclusion, it is clear that non-Caucasian populations have some unique phenotypic expressions of 22qDS. It is imperative that clinicians maintain a high index of suspicion for patients with 22qDS.
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    Open Access
    Origins of Systemic to Pulmonary Collateral Arteries and their Relative Frequencies in Patients with Pulmonary Artery Atresia or Stenosis as determined using Multidetector Computed Tomography Angiography
    (2018) Smith, Mark Royden; Banderker, Ebrahim; De Decker, Rik
    INTRODUCTION: Critical to the management of pulmonary atresia (PA) or pulmonary stenosis (PS) is accurate and comprehensive knowledge of the vascular network supplying the lungs. This vascular network can be exceedingly complex as it may include a wide variation of systemic to pulmonary collateral arteries (SPC/s). AIM: This study aims to guide radiologists, cardiologists and cardiothoracic surgeons in their search for SPC/s and to recommend an accurate, informative and standardised nomenclature system for SPC/s based on the relative frequency of SPC/s origins in patients with PA or PS identified using multi-detector computed tomography arteriography (MDCTA). METHOD: In this retrospective descriptive study a data set was created incorporating MDCTA cases performed at Red Cross War Memorial Children’s Hospital, Cape Town, South Africa (RCWMCH) during the period November 2013 to November 2017. Using multiple, temporally separated readers, cases with PA or PS were identified and further analysed for systemic to pulmonary circulation collateral supply, including patent ductus arteriosus (PDA) and SPC/s with special attention given to their origins and destinations. RESULTS: Of 145 eligible MDCTAs, 93 demonstrated PA or PS of which 31 demonstrated systemic to pulmonary circulation collateral supply, 17 with a PDA, 19 with a single SPC/s, 5 with both a PDA and SPC/s and 14 with multiple SPC/s. The majority of SPC/s originated from the descending aorta, however, there were numerous other intra- and extrathoracic systemic arterial vessels of origin. CONCLUSIONS: The recommended systematic search pattern for systemic to pulmonary circulation collateral supply as determined by their relative frequencies of origin should be for a PDA first, then for SPC/s originating from the descending aorta (DA), aortic arch (AArch), left subclavian artery (LSCA) and right subclavian artery (RSCA). However, SPC/s may arise from numerous other sources and no systemic artery can be neglected. “Systemic to pulmonary collateral artery/s” (SPC/s) is a more accurate general term than “major aortopulmonary artery/s” (MAPCA/s), as 40% of SPC/s do not originate from the aorta. The large variability in location of SPC/s makes a classification system impractical and favours descriptive characterization, the simplest form of which must include the origin and destination of each SPC/s, for example (DA to Left main pulmonary artery (LMPA)) or (AArch to right main pulmonary artery (RMPA)).
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    Surprises of off-label drug use - where had all the Prostin gone?
    (2009) De Decker, Rik; Gordon-Graham, Eugenie; Seller, Neil; Lawrenson, , John
    The off-label use of drugs is common, particularly in paediatrics, where many drugs have yet to undergo the rigorous scrutiny demanded by authorities such as the Medicines Control Council (MCC) and the US Food and Drug Administration (FDA) before registration.1,2 Yet some drugs (e.g. paracetamol, salbutamol) are so commonplace in paediatric practice that it may come as a surprise that their use is indeed off-label in many circumstances. Problems may arise when an important drug in everyday (off-label) use is unexpectedly in short supply. An example is dinoprostone, marketed in South Africa as Prostin E2 by Pfizer South Africa (but curiously not listed on their website). Its registered use in South Africa is for induction of labour (as an oral 0.5 mg tablet), yet it is commonly used in South Africa for the emergency maintenance of ductal patency in newborn babies.