Browsing by Author "Wessels, G."

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    An analysis of prognostic variables in acute lymphocytic leukaemia in a heterogenous South African population
    (1997) Wessels, G.; Hesseling, P. B.; Buurman, M.; Oud, C.; Nel, E. D.
    The records of all 96 children below the age of 15 years diagnosed with acute lymphoblastic leukaemia at Tygerberg Hospital in the Republic of South Africa between 1983 and 1995 were reviewed to determine risk factors which may predict poor outcome. Age < 2 and > 8 years, and white cell count > 20 x 109/l at diagnosis were significant predictors of poor outcome. Sex, FAB classification, immunophenotype, hepatomegaly, splenomegaly, BFM risk score, and the presence of mediastinal glands did not predict outcome. The presence of the established risk factors could not adequately explain the difference in 5-year event-free survival in the three ethnic groups which was 67 per cent in white, 17 per cent in black, and 38 per cent in children of mixed ethnic origin. In an attempt to improve survival in black children, our stratification of risk groups will in future be based on factors that include ethnicity, age and WCC ≤ 20 x 109/l at diagnosis. Pediatric oncology services in developing countries should adapt therapy to the risk factors of their local populations.
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    Follow-up of a suspected excess of brain tumours among Namibian children
    (Health and Medical Publishing Group (HMPG), 2005-10) Preston-Martin, S.; Wessels, G.; Hecht, S.; Hesseling, P. B.
    To the Editor: The aim of this follow-up study was to further investigate a suggested excess of childhood brain tumours (CBT) among Herero children in Namibia from 1983 to 1988. Incidence rates of primary brain tumours among Herero children were found to be 4 times higher than rates among Namibian children in any of the 10 other tribal groups or among children of European origin. The causes of CBTs remain largely unknown. The only established causes are ionizing radiation and predisposing inherited syndromes. A particularly compelling hypothesis is that exposure during gestation to N-nitroso compounds (NOCs) may lead to the development of CBT. This hypothesis was suggested by experimental work in which 100% production of nervous system (NS) tumours in rat offspring resulted from transplacental exposure to the neurocarcinogen ethylnitrosourea (ENU) or to low levels of the precursor compounds sodium nitrite and ethyl urea added to the food and drinking water of pregnant rats
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    Haemophilia patients aged 0-18 years in the Western Cape
    (Health & Medical Publishing Group, 2003) Hazewinkel, M. H.; Hoogerwerf, J. J.; Hesseling, P. B.; Hartley, P.; MacLean, P. E.; Peters, M.; Wessels, G.
    Objectives. To record the number of haemophiliacs aged 0 - 18 years in the Western Cape (WC), what event led to the diagnosis, the level of clotting factor, treatment, functional status of their joints and impact of the disease on the family. Design. A prospective study of patients registered with the South African National Haemophilia Registry and new patients, utilising the patients' paediatricians, hospital records, patient and guardian interviews, physical examination and provincial nurse haemophilia co-ordinators. Setting. Haemophilia care centres, at the three WC academic hospitals, regional hospitals and homes of patients. Two elective medical students, MHH and JJH, collected the information. Subjects. All boys with confirmed haemophilia A or B in the WC. Outcome measures. Events that led to diagnosis, degree of haemophilia, use of clotting factor, functional status, and effect on family. Results. Of 78 patients (59 haemophilia A, 19 haemophilia B) identified, 49 could be studied. Forty-three per cent had severe, 29% moderate and 22% mild disease (6% unknown). Family history was present in 49%, but led to diagnosis in only 12%. The most common first symptoms were subcutaneous and mucosal bleeding. Delay in diagnosis varied from 0 to 9 months. Twenty-nine per cent of guardians were suspected of child abuse. RSA produced clotting factor was used 'on demand' in 73% of patients, for periodic prophylaxis in 20% and as continuous prophylaxis in 7%. Joints were functionally restricted in 43% of patients. The majority of guardians (59%) said the disease had a major impact on the family. Conclusions. The diagnosis of haemophilia in children with a positive family history was often delayed. Haemophilia causes significant morbidity in our patients and their families.
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    Incidence and frequency rates of childhood cancer in Namibia
    (Health & Medical Publishing Group, 1997) Wessels, G.; Hesseling, P. B.
    Objective. To estimate the extent of paediatric malignancy in an African country and to compare these findings with paediatric cancer rates in other countries. Design. A retrospective descriptive study which calculated incidence and frequency rates from the data obtained from a 6-year survey of childhood cancer in Namibia. Setting. Children from the general community who were referred by primary care physicians or clinics and diagnosed in peripheral district hospitals or a tertiary care institution. Patients. A total of 163 children less than 15 years of age diagnosed with any malignant neoplasm, intracranial tumour or histiocytosis between 1983 and 1988. Intervention. None. Main outcome measures. The minimum overall incidence of childhood cancer recorded in Namibia was lower than the rates usually reported by economically privileged countries. The rates of certain malignancies corresponded to the rates recorded in other African countries. Results. The overall incidence of childhood cancer was 55.5 per million. Tumours of the central nervous system occurred most commonly (18%), followed by renal tumours (14%), leukaemia (12%) and lymphoma (11.5%). The 5.8 per million incidence rate of retinoblastoma was similar to the rates recorded in other African countries but higher than in the UK or the USA. The incidence rates per million children for renal tumours, malignant bone tumours and soft-tissue sarcomas were 7.4, 4.8 and 5.2, respectively, which correspond with the rates in Western Europe and the USA. The incidence rate of CNS tumours was only 9.3 per million. Both leukaemia (6.5 per million) and lymphoma (6.3 per million) had rates far lower than those recorded in central Africa or developed Western countries. Conclusion. The incidence pattern of childhood cancer in Namibia demonstrates features of both the patterns described as typical for Africa and those described for industrialised countries.
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    Incidence of acute lymphoblastic leukaemia in white and coloured children in the Western Cape
    (Health & Medical Publishing Group, 2004) Hesseling, P. B.; Hartley, P.; Zietsman, L.; Van Lill, S.; Preston-Martin, S.; Wessels, G.
    Objectives. To record the age-specific incidence rate (ASIR) for diagnosed acute lymphoblastic leukaemia (ALL) in coloured and white children aged 0-12 years in the Western Cape (WC). Design. A retrospective population-based study using the 1991 population census to calculate the mean annual childhood population and the ASIR for ALL in the 0-4, 5-9 and 10-12-year age groups in rural and Cape Town metropolitan areas for the period 1983-1999. Odds ratios were calculated using EpiInfo 2000. Setting. Registry records of the paediatric cancer units at Tygerberg and Red Cross War Memorial Children's hospitals where all children with ALL in the WC were initially treated. Subjects. All white and coloured children aged 0-12 years diagnosed as having ALL from 1983-1999. Outcome measures. The ASIR by age and ethnic group in rural and metropolitan patients in the WC. Results. The estimated annual childhood population in 1991 was 709 151 with 80.4% coloured and 19.6% white children, of whom 60% were resident in the Cape Town metropolitan area and 40% in the rural area of the WC. Of 246 children with ALL diagnosed in the period 1983 - 1999, 144 were male and 102 female. The ASIR in coloured children aged 0 - 4 years was 17.1/106 in the rural and 30.5/106 in the metropolitan area, compared with 55.7/106 and 56.2/106 respectively in white children. In the 5-9-year age group the ASIR in coloured children was 10.0/106 in the rural and 16.6/106 in the metropolitan area compared with 27.6/106 and 26.7/106 respectively in white children. The 10-12-year age group had comparable incidence rates in both populations and geographical areas. Only one case occurred within a 20 km radius of the Koeberg nuclear reactor. Conclusions. White children have an ASIR for ALL comparable to rates of diagnosis in the USA, while only half as many coloured children aged 0-9 years were diagnosed in both the rural and metropolitan areas. This contrast may indicate significant underdiagnosis of ALL in coloured children over the period in question. The change in health policy since 1994, which has improved access to primary health care, may improve the rate of diagnosis among coloured and black children.
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    The necessity for T-cryptantigen activation screening in babies with necrotising enterocolitis
    (Health & Medical Publishing Group, 1996) Kirsten, G. F.; Smith, J.; Pieper, C.; Bird, A.; Wessels, G.; Riphagen, S.; Moore, S.
    Objective. To determine the prevalence of T-cryptantigen activation (TCA) and its predictive value for severity of necrotising enterocolitis (NEC) in babies. Study design. Prospective descriptive. Study population. Thirty-four babies with NEC were prospectively screened for TCA at Tygerberg Hospital over a 6-month period. TGA screening was done by testing for red blood cell agglutination by the common peanut lectin, Arachis hypogea. Once TCA was confirmed, only washed red cells were administered to the babies and plasma-containing blood products were avoided. NEC was divided into suspected NEC (stage 1), classic NEC (stage 2) and fulminant NEC (stage 3). Main outcome measures. Prevalence of TCA in babies with various stages of NEC; the association between TCA and bowel necrosis, need for surgery and mortality. Results. TCA was positive in 8 (24%) of the babies in this study. Six babies (18%) had stage 1 NEC, 10 (29%) had stage 2 NEC and 18 (53%) had fulminating or stage 3 NEC. All 18 babies with stage 3 NEC required surgery and TCA was present in 8 (47%) of them. Twelve babies (35%) died, 3 with TCA and 9 with no TCA. Babies with TCA had portal venous gas on abdominal radiographs (P = 0.037) and stage 3 NEC (P = 0.003) more often than babies with no TCA. Conclusions. A strong association was noted between TCA and the fulminant form of NEC with bower necrosis. TCA in a baby with NEC should alert the surgeon to the possibility of severe disease and the need to avoid plasma-containing blood products. Blood banks are urged to introduce routine screening for TCA in all babies with NEC.
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    Nosocomial endocarditis due to extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a child
    (Health & Medical Publishing Group, 2001) Shipton, S. E.; Cotton, M. F.; Wessels, G.; Wasserman, E.
    Extended-spectrum beta-lactamase-producing organisms resistant to third-generation cephalosporins have been increasingly implicated in nosocomial infection.'Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESKP) has been endemic at Tygerberg Hospital since 1993, and has recently been implicated in an outbreak of sepsis in the neonatal unit.' Despite improved infection control practices, sporadic episodes of nosocomial sepsis due to ESKP still occur both in the neonatal unit and in other paediatric wards. To the best of our knowledge this is the first report of a child with endocarditis due to ESKP.
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    A prospective study of long-term use of amikacin in a paediatrics department : indications, administration, side-effects, bacterial isolates and resistance
    (Health & Medical Publishing Group, 1990) Hesseling, P. B.; Mouton, W. L.; Henning, P. A.; Kirsten, G. F.; Spruyt, L. L.; Schraader, E. B.; Wessels, G.; Grassman, R.
    Amikacin (Amikin; B-M) was used as the only aminoglycoside for 18 months in a paediatric department within a general hospital because of high levels of resistance of Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterobacter cloacae isolates to tobramycin, gentamicin and netilmicin. Between 1 February 1987 and 31 July 1988, 816 children were treated with a slow intravenous injection at a standardised dose adjusted for weight and age. Respiratory disease was present in 35,8% of 537 neonates, 56,4% of 190 infants and 70,9% of 89 older children. Escherichia coli (65 isolates), Klebsiella species (59 isolates), Enterobacter species (26 isolates) and P. aeruginosa (22 isolates) constituted the most common Gram-negative pathogens. The positive blood culture yield was 7,8%. Satisfactory median peak and trough serum amikacin levels were achieved. No significant renal side-effects were noted. Severe bilateral hearing loss in 1 low-birthweight infant resulted from inadvertent overdosage. At the end of this 18-month surveillance period 97,7% of E. coli, 98,6% of K. pneumoniae, 96,3% of E. cloacae, and 98,0% of P. aeruginosa isolates remained sensitive to amikacin, while resistance of K. pneumoniae to tobramycin, netilmicin and gentamicin decreased significantly (P < 0,003, P < 0,001 and P < 0,007 respectively; chi-square test).