Browsing by Author "Lawrenson, John"

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    Open Access
    Infant and Childhood Infective Endocarditis in the Western Cape, South Africa: A Retrospective Review
    (2020) Willoughby, Mark; Zühlke, Liesl; Comitis, George; Fourie, Barend; Lawrenson, John; Perkins, Susan; Basera, Wisdom
    Introduction Infective endocarditis is a microbial infection of the endothelial surface of the heart, predominantly the heart valves, that is associated with high mortality and morbidity. Few contemporary data exist regarding affected children in our context. Aims and Objectives: We aimed to describe the profile and treatment outcomes of infant and childhood endocarditis at our facilities. Methods: This is a retrospective review of infants and children with endocarditis at two public-sector hospitals in the Western Cape Province of South Africa over a 5-year period. Patients with “definite” and “possible” endocarditis according to Modified Duke Criteria were included in the review. Results: Forty-nine patients were identified for inclusion; 64% of patients met “definite” and 36% “possible” criteria. The in-hospital mortality rate was 20%; 53% of patients underwent surgery with a post-operative mortality rate of 7.7%. The median interval from diagnosis to surgery was 20 days (interquartile range 9-47 days). Valve replacement occurred in 28% and valve repair in 58%. There was a significant reduction in valvular dysfunction in patients undergoing surgery and only a marginal improvement in patients treated medically. Overall, 43% of patients had some degree of residual valvular dysfunction. Conclusion: Endocarditis is a serious disease with a high in-hospital mortality and presents challenges in making an accurate diagnosis. Despite a significant reduction in valvular dysfunction, a portion of patients had residual valvular dysfunction. Early surgery is associated with a lower mortality rate, but a higher rate of valve replacement when compared to delayed surgery.
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    Left ventricular submitral aneurysms
    (2007) Du Toit, Henning; Hewitson, John; Lawrenson, John
    Retrospective institutional review of the pathology, aetiology classification and surgical management of left ventricular submitral aneurysms (LVSMA). These aneurysms are a well recognized but relatively rare disease found commonly in patients from African ancestry. The series comprises 20 consecutive patients treated surgically at three institutions from 1985 to 2002. Natural history, clinical presentation, histo-pathological findings, suspected aetiology, operative techniques, along with a discussion of the condition is presented. There were 10 female and 10 male patients and the mean age was 17+-6 (range 8-34) years. Patients were grouped as to the degree of posterior mitral annulus involvement by the aneurysm. In Group I, (n=12) a single aneurysm neck was found. In Group II, (n=3) multiple necks and in Group III, (n=5) involvement of the entire posterior annulus by teh aneurysm was found. Mean age in Group III (29 +/-5 years) was older than that of Groups I and II (15.5 +/- 4 years) suggesting a progressive nature of these aneurysms to enlarge. Clinically patients were in New YOrk Heart Association (NYHA) class I-IV. An intra-cardiac surgical approach was used in 11, extra-cardiac approach in two and a combined approach in seven patients. Mitral valve repair was attempted in 14 patients, with two intra-operative mitral valve repair failures. Failure to control the aneurysm neck (n=2) and failure of mitral valve repair (n=2) resulted in subsequent re-operation. There was no operative mortality. Histology of the aneurysm tissue suggested co-existing rheumatic heart disease in two, tuberculosis in four and infective endocarditis in two. Unknown or congenital disease was postulated in nine patients. Although LVSMA are thought to be congenital, 8 out of 20 patients (40%) had evidence of co-existent inflammatory pathology. The etiology of LVSMA remains uncertain. Many are thought to be congenital, but the findings in this study strongly support the view that rheumatic disease, chronic infections and malnutrition also play a role. A new classification is proposed based on the pathological findings. Involvement of the entire annulus in the older patients suggests a possible progressive nature of the disease. Surgery should be the difinitive therapy in all patients. Surgical approach must be individualized but the intra cardiac approach is suitable for the surgical repair in most cases. Success in mangement is dependent on the appropriate understanding of the relationship between aneurysm and valve.
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    Sydenham's chorea - clinical and therapeutic update 320 years down the line
    (2006) Walker, Kathleen; Lawrenson, John; Wilmshurst, Jo M
    Post-streptococcal neuropsychiatric movement disorders (PNM) were first described in the Middle Ages, but today more than 300 years later, confusion remains surrounding the terminology, treatment and monitoring of these conditions. Rheumatic fever is currently the major cause of acquired heart disease among children in South Africa.1 The incidence of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) is not declining. Recent figures quote the incidence of rheumatic fever as 0.6 - 0.7/1 000 population in the USA and Japan compared with 15 - 21/1 000 population in Asia and Africa.2 In a study conducted in 1975 in Soweto, South Africa, 12 050 schoolchildren were examined and 19.2/1 000 had rheumatic heart disease.3 A 2002 report from a cardiology workshop highlighted the belief among clinicians that South Africa is currently in the midst of a rheumatic fever epidemic.4,5 Sydenham’s chorea (SC) is a major manifestation of ARF. Accordingly, in the South African context when PNMs are diagnosed, treatment strategies must always include the prevention of RHD.
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    The Drakensberg Declaration on the Control of Rheumatic Fever and Rheumatic Heart Disease in Africa
    (2006) Mayosi, Bongani; Robertson, Kate; Volmink, Jimmy; Adebo, Wole; Akinyore, Kingsley; Amoah, Albert; Bannerman, Charles; Biesman-Simons, Shan; Jonathan, Carapetis; Cilliers, Antoinette; Commerford, Patrick; Croasdale, Anne; Damasceno, Albertino; Dean, Jenny; Dean, Michael; de Souza, Robert; Filipe, Antonio; Hugo-Hamman, Chris; JurgensClur, Sally-Ann; Kombila-Koumba, Pierre; Kotzenberg, Christelle; Lawrenson, John; Manga, Pravin; Matenga, Jonathan; Mathivha, Tshimbi; Mntla, Phindile; Mocumbi, Ana; Mokone, Tiny; Ogola, Elijah; Omokhodion, Samuel; Palweni, Chapman; Pearce, Adrian; Salo, Avril; Thomas, Baby; Walker, Kathie; Wiysonge, Charles; Zaher, Salah
    This paper reviews some research studies on tillage methods influencing soil and moisture conservation in the eastern African countries of Kenya, Tanzania, Malawi and Ethiopia during the past four decades. Most of these studies were conducted in marginal rainfall (semi arid ) areas and on shallow soils of various textures (sandy clay loam, sandy clay, clay and loam). The studies were meant to establish the effects of tillage and residue management practices on physico-chemical soil properties (i.e. structure, bulk density, soil moisture and organic matter contents), runoff and infiltration. This review emphasizes the importance of appropriate tillage and residue management methods (contour bunds and terraces, minimum tillage, tied ridging, mulching and conventional tillage) in providing soil conditions favourable for soil moisture conservation and subsequent crop performance and yield on smallholder farms