Browsing by Author "Rensburg, Megan A."

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    Bolus administration of intravenous glucose in the treatment of hyperkalemia : a randomized controlled trial
    (Karger, 2014-02) Chothia, Mogamat-Yazied; Halperin, Mitchell L.; Rensburg, Megan A.; Hassan, Mogamat Shafick; Davids, Mogamat Razeen
    Background: Hyperkalemia is a common medical emergency that may result in serious cardiac arrhythmias. Standard therapy with insulin plus glucose reliably lowers the serum potassium concentration ([K + ]) but carries the risk of hypoglycemia. This study examined whether an intravenous glucose- only bolus lowers serum [K + ] in stable, nondiabetic, hyperkalemic patients and compared this intervention with insulin-plus-glucose therapy. Methods: A randomized, crossover study was conducted in 10 chronic hemodialysis patients who were prone to hyperkalemia. Administration of 10 units of insulin with 100 ml of 50% glucose (50 g) was compared with the administration of 100 ml of 50% glucose only. Serum [K + ] was measured up to 60 min. Patients were monitored for hypoglycemia and EKG changes. Results: Baseline serum [K + ] was 6.01 ± 0.87 and 6.23 ± 1.20 mmol/l in the insulin and glucose-only groups, respectively (p = 0.45). At 60 min, the glucose-only group had a fall in [K + ] of 0.50 ± 0.31 mmol/l (p < 0.001). In the insulin group, there was a fall of 0.83 ± 0.53 mmol/l at 60 min (p < 0.001) and a lower serum [K + ] at that time compared to the glucose-only group (5.18 ± 0.76 vs. 5.73 ± 1.12 mmol/l, respectively; p = 0.01). In the glucose-only group, the glucose area under the curve (AUC) was greater and the insulin AUC was smaller. Two patients in the insulin group developed hypoglycemia. Conclusion: Infusion of a glucose-only bolus caused a clinically significant decrease in serum [K + ] without any episodes of hypoglycemia.
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    Chronic kidney diseases in mixed ancestry South African populations : prevalence, determinants and concordance between kidney function estimators
    (BioMed Central, 2013-04) Matsha, Tandi E.; Yako, Yandiswa Y.; Rensburg, Megan A.; Hassan, Mogamat S.; Kengne, Andre P.; Erasmus, Rajiv T.
    ABSTRACT: Population-based data on the burden of chronic kidney disease (CKD) in sub-Saharan Africa is still very limited. We assessed the prevalence and determinants of CKD, and evaluated the concordance of commonly advocated estimators of glomerular filtration rate (eGFR) in a mixed ancestry population from South Africa. Methods Participants were a population-based sample of adults selected from the Bellville-South community in the metropolitan city of Cape Town. eGFR was based on the Cockroft-Gault (CG), Modification of Diet in Kidney Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) equations (with and without adjustment for ethnicity). Kidney function staging used the Kidney Disease Outcome Quality Initiative (KDOQI) classification. Logistic regressions and kappa statistic were used to investigate determinants of CKD and assess the agreement between different estimators. Results The crude prevalence of CKD stage 3–5 was 14.8% for Cockcroft-Gault, 7.6% and 23.9% respectively for the MDRD with and without ethnicity correction, and 7.4% and 17.3% for the CKD-EPI equations with and without ethnicity correction. The highest agreement between GFR estimators was between MDRD and CKD-EPI equations, both with ethnicity correction, Kappa 0.91 (95% CI: 0.86-0.95), correlation coefficient 0.95 (95% CI: 0.94-0.96). In multivariable logistic regression models, sex, age and known hypertension were consistently associated with CKD stage 3–5 across the 5 estimators. Conclusions The prevalence of CKD stages greater than 3 is the highest reported in Africa. This study provides evidence for support of the CKD-EPI equation for eGFR reporting and CKD classification.
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    Distribution and association of hs-CRP with cardiovascular risk variables of metabolic syndrome in adolescent learners
    (AOSIS Publishing, 2012-06) Rensburg, Megan A.; Matsha, Tandi; Hoffman, Mariza; Hassan, Mogamat S.; Erasmus, Rajiv T.
    Objective: Metabolic syndrome (MetS) and its associated cardiovascular risk are on the increase in children. High-sensitivity C-reactive protein (hs-CRP) has emerged as a useful marker for inflammation associated with atherosclerosis and cardiovascular disease. Our aim was to determine the distribution of hs-CRP in an effort to identify the MetS variable that is critical in modulating plasma CRP levels in a population of South African adolescents. Design: A cross-sectional analytical study design was used for this investigation, where the dependent and independent variables were measured simultaneously. Methods: Anthropometric variables, blood pressure, fasting blood glucose and lipids were performed on 324 consenting learners aged 15–18 years from three different ethnic groups (Black, White and Coloured). The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) for ages 15–18 year olds was used to define MetS. Results: The prevalence of MetS and obesity was 3.7% and 7.1%, respectively. The hs-CRP levels were significantly higher in subjects with a waist-circumference greater than the 90th percentile (p < 0.01) and in obese learners with MetS, but was lower in adolescents with normal weight and MetS. Median hs-CRP levels increased with an increasing number of metabolic abnormalities and exceeded 3 mg/L in 19% of adolescents. Gender and ethnic differences were observed. Conclusion: Our findings suggest that obesity and waist circumference appear to be major mediators of hs-CRP levels in South African adolescents.
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    Gitelman syndrome in a South African family presenting with hypokalaemia and unusual food cravings
    (BioMed Central, 2017-01-26) Van der Merwe, Pieter Du Toit; Rensburg, Megan A.; Haylett, William L.; Bardien, Soraya; Davids, M. Razeen
    Background Gitelman syndrome (GS) is an autosomal recessive renal tubular disorder characterised by renal salt wasting with hypokalaemia, metabolic alkalosis, hypomagnesaemia and hypocalciuria. It is caused by mutations in SLC12A3 encoding the sodium-chloride cotransporter on the apical membrane of the distal convoluted tubule. We report a South African family with five affected individuals presenting with hypokalaemia and unusual food cravings. Methods The affected individuals and two unaffected first degree relatives were enrolled into the study. Phenotypes were evaluated through history, physical examination and biochemical analysis of blood and urine. Mutation screening was performed by sequencing of SLC12A3, and determining the allele frequencies of the sequence variants found in this family in 117 ethnically matched controls. Results The index patient, her sister, father and two aunts had a history of severe salt cravings, fatigue and tetanic episodes, leading to consumption of large quantities of salt and vinegar. All affected individuals demonstrated hypokalaemia with renal potassium wasting. Genetic analysis revealed that the pseudo-dominant pattern of inheritance was due to compound heterozygosity with two novel mutations: a S546G substitution in exon 13, and insertion of AGCCCC at c.1930 in exon 16. These variants were present in the five affected individuals, but only one variant each in the unaffected family members. Neither variant was found in any of the controls. Conclusions The diagnosis of GS was established in five members of a South African family through clinical assessment, biochemical analysis and mutation screening of the SLC12A3 gene, which identified two novel putative pathogenic mutations.
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    Hypernatraemia in South African hospitalized patients
    (African Association of Nephrology, 2019) Abohajir, Ali; Rensburg, Megan A.; Davids, M. Razeen
    Background: Hypernatraemia is a common electrolyte problem in hospitalized patients and is associated with a high mortality rate. We determined the incidence, causes, management, and outcomes of hypernatraemia in adult hospitalized patients at a large South African tertiary hospital. Methods: A retrospective study was conducted at Tygerberg Hospital in Cape Town, South Africa. Adult patients with hypernatraemia (at least one serum sodium concentration ≥150 mmol/L) during a 3-month period in 2014 were identified from our laboratory database for inclusion. Results: There were 204 patients with hypernatraemia, a prevalence of 1.5%. Of these patients, 101 (49.5%) were male, and the mean age was 53 years. There were 66 patients (32.4%) who had hypernatraemia on admission, and 138 who developed it during the course of their stay in hospital. The overall in-hospital mortality was 38.7%, with higher rates for older patients and those with more severe degrees of hypernatraemia. Contributory causes which were most commonly present included dehydration/hypovolaemia (45%), followed by sepsis (39%). Net sodium gain, rather than water deficit, was identified as the main mechanism in most of the patients who developed hypernatraemia in the intensive care units. We found little evidence of any diagnostic work-up and also found that the details of fluid therapy and intake–output charting were poorly documented. Conclusions: There is a very high mortality rate in our hospitalized patients with hypernatraemia. The diagnostic work-up and therapy were often inadequate or poorly documented. The management of this important condition needs to be improved with the aid of standardized protocols.