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Masters Degrees (Medicine)

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Browsing Masters Degrees (Medicine) by Author "Blaylock, Roger."

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    The clinical natural history of snakebite victims in Southern Africa.
    (2000) Blaylock, Roger.; Robbs, John Vivian.
    The author wrote a dissertation for the Mmed Sc degree entitled The Clinical Natural History of Snakebite in Southern Africa, which dealt with the epidemiology of snakebite and the clinico-pathological events in snakebite victims. This thesis is a sequel on the management of snakebite victims. Publications on the overall management of snakebite in the Southern African region that include original scientific research are those of F.W. Fitzsimons (1912), F.W. Fitzsimons (1929) (assisted by V.F.M. Fitzsimons), P.A. Christensen (1955, 1966, 1969) and Christensen & Anderson (1967). Subsequent books, pamphlets and journal articles have rehashed this knowledge or advocated methods of treatment developed in other countries. An example of the latter is the pressure immobilisation prehospital measure advocated for snakebites in Australia (Sutherland et aL, 1979, 1981, 1995), which I regard as benefiting less than 1% of snakebite victims here and being deleterious in most cases. In view of the paucity of research done in Southern African in recent years, many questions remain unanswered, and some strongly held views are without logical or scientific foundation. Most of these questions arose prior to the writing of this thesis, and others arose when the data were analysed. The following are some questions on the management of snakebite that have still have to be addressed. Is vaccination against snakebite possible and practical? Are folk and traditional remedies advantageous or deleterious? How commonly are they used? Immobilisation of the bitten part and the patient is an internationally recognised aid measure, but is this relevant to the Southern African situation? Tourniquet use in the case of necrotising venoms is considered to aggravate or precipitate necrosis. Does immediate active movement following a bite ameliorate or prevent necrosis without increasing mortality? The majority of clinicians recommend antibiotic prophylaxis, but is this necessary for all snakebites, against which bacteria should antibiotics be administered, and what is the source of these bacteria? Should antivenom be administered to all snakebite victims: for species-specific bites, only if envenomation is present, for severe envenomation, or not at all? Acute adverse reactions to South African manufactured snakebite antivenom has been variously recorded as less than 1% (Visser & Chapman 1978) up to 76% (Moran et al., 1998). What is the truth? Is syndromic management of snakebite efficacious or is it essential to identify the particular snake species? Is the present liberal use of fasciotomy necessary? Is there an optimum time to debride necrotic areas and is surgery necessary at all? Is paresis or paralysis due to neurotoxic envenomation always the result of a post-synaptic block? Would such a block respond to neostigmine or prostigmine in a similar way to post-synaptic anaesthetic muscle relaxants? Is heparin of value when procoagulant toxins induce a consumption coagulopathy? Do fibrinstabilising agents or fibrinolytics have a role? Does the management of pregnant snakebite patients differ from that of non-pregnant patients? Is snake venom teratogenic? Does snake venom ophthalmia frequently lead to blindness? Are steroids, NSAIDs and antihistaminics, which are commonly used in the management of snakebite, of proven value? This thesis attempts to answer these questions and more, and comprises six sections. The first section deals with pre-hospital management, the second with infection which may occur at the bite site wound, the third with SAIMR snakebite antivenom, the fourth with the three envenomation syndromes, the fifth with snakebite in pregnancy, venom ophthalmia and other treatment modalities, and the sixth section includes a summary, appendix and references. Unless otherwise stated, the materials and methods of each chapter are based on 336 snakebite victims admitted to Eshowe Hospital, KwaZulu-Natal, from January 1990 - July 1993 and other victims treated by the author, the data of which have been prospectively maintained. This has been an ongoing process up to the present time.