Low dose subcutaneous adrenaline to prevent acute adverse reactions to antivenom serum in people bitten by snakes: randomised, placebo controlled trial.
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OBJECTIVE: To assess the efficacy and safety of low dose adrenaline injected subcutaneously to prevent acute adverse reactions to polyspecific antivenom serum in patients admitted to hospital after snake bite. DESIGN: Prospective, double blind, randomised, placebo controlled trial. SETTING: District general hospital in Sri Lanka. SUBJECTS: 105 patients with signs of envenomation after snake bite, randomised to receive either adrenaline (cases) or placebo (controls) immediately before infusion of antivenom serum. INTERVENTIONS: Adrenaline 0.25 ml (1:1000). MAIN OUTCOME MEASURES: Development of acute adverse reactions to serum and side effects attributable to adrenaline. RESULTS: 56 patients (cases) received adrenaline and 49 (controls) received placebo as pretreatment. Six (11%) adrenaline patients and 21 (43%) control patients developed acute adverse reactions to antivenom serum (P=0.0002). Significant reductions in acute adverse reactions to serum were also seen in the adrenaline patients for each category of mild, moderate, and severe reactions. There were no significant adverse effects attributable to adrenaline. CONCLUSIONS: Use of 0.25 ml of 1:1000 adrenaline given subcutaneously immediately before administration of antivenom serum to patients with envenomation after snake bite reduces the incidence of acute adverse reactions to serum. (+info)
Myasthenic syndrome of snake envenomation: a clinical and neurophysiological study.
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In this prospective study, 65 consecutive patients with neurological manifestations after snake envenomation, were examined in order to describe the natural history of the reversible nature of muscle weakness. Snake envenoming led to a completely reversible muscle paralysis involving the external ocular muscles with sparing of the pupils, muscles of mastication, facial muscles, palatal muscles, neck and proximal limb muscles. The deep tendon reflexes were preserved with no sensory abnormalities. The muscular weakness usually set in within an hour of envenomation and lasted up to 10 days, with fatigability lasting for 12 days. Respiratory muscle paralysis led to ventilatory failure needing ventilation in severely envenomed patients. Motor and sensory nerve conduction were normal with normal resting compound motor action potentials on electromyography. Repetitive nerve stimulation gave rise to a decremental response during high frequency stimulation. The edrophonium test gave negative results. These manifestations are due to abnormalities of neuromuscular transmission and are not typical of myasthenia gravis. As the exact pathophysiology of venom-related neurotoxicity is not known, it is suggested that the neurological manifestations of snake envenoming be designated a myasthenic syndrome. Further studies to isolate the neurotoxin and its mechanism and exact site of blocking at the neuromuscular junction would pave the way for the development of a novel long-acting neuromuscular blocking agent. (+info)
Sequential randomised and double blind trial of promethazine prophylaxis against early anaphylactic reactions to antivenom for bothrops snake bites.
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OBJECTIVE: To investigate the efficacy of the H1 antihistamine promethazine against early anaphylactic reactions to antivenom. DESIGN: Sequential randomised, double blind, placebo controlled trial. SETTING: Public hospital in a venom research institute, Sao Paulo, Brazil. PARTICIPANTS: 101 patients requiring antivenom treatment after being bitten by bothrops snakes. INTERVENTION: Intramuscular injection of promethazine (25 mg for adults and 0.5/kg for children) or placebo given 15-20 min before starting intravenous infusion of antivenom. MAIN OUTCOME MEASURES: Incidence and severity of anaphylactic reactions occurring within 24 hours after antivenom. RESULTS: Reactions occurred in 12 of 49 patients treated with promethazine (24%) and in 13 of 52 given placebo (25%); most were mild or moderate. Continuous sequential analysis indicated that the study could be interrupted at the 22nd untied pair, without preference for promethazine or placebo. CONCLUSION: Prophylaxis with promethazine does not prevent early reactions. Patients should be observed carefully during antivenom infusion and the subsequent few hours. (+info)
A new monospecific ovine Fab fragment antivenom for treatment of envenoming by the Sri Lankan Russell's viper (Daboia Russelii Russelii): a preliminary dose-finding and pharmacokinetic study.
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Russell's viper is the most important cause of life-threatening snake bite and acute renal failure in Sri Lanka. Only equine polyspecific antivenoms imported from India are available. They have not proved effective clinically or in clearing venom antigenemia and they frequently cause reactions. In an attempt to reduce mortality and morbidity, a new monospecific ovine Fab fragment antivenom (PolongaTab; Therapeutic Antibodies, Inc., London, United Kingdom) was raised against Sri Lankan Russell's viper venom. In a preliminary dose-finding study in 35 patients, an initial dose of 3-4 g restored blood coagulability permanently and stopped systemic bleeding, even in severely envenomed patients. Venom antigenemia disappeared within 1 hr of antivenom treatment but recurred, probably as a result of continued absorption of venom from the site of the bite, after the rapid clearance of therapeutic antibody. Twelve patients (34%) experienced early reactions that were usually mild and always responded to epinephrine. (+info)
Epidemiological and clinical differences of snake bites among children and adults in south western Saudi Arabia.
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OBJECTIVES: To compare the clinical course and complications of snake bite in children and adults. METHODS: A retrospective review of 66 patients (28 children and 38 adults) admitted after snake bites for management at the Prince Abdullah Hospital in Bisha, in the south western part of Saudi Arabia, during the period May 1992 to May 1995. RESULTS: No significant difference was found in time of bite, site of bite, and sex preference between adults and children. Local complications, such as tissue necrosis, were commoner in children (14%) than in adults (5%). Systemic manifestations were also more commonly seen in children than in adults; this is possibly due to a higher ratio of injected venom to body mass in children. Leukocytosis was seen in 54% of children (adults 13%), a low haemoglobin concentration in 14% of children (adults 11%), prolonged prothrombin and partial thromboplastin times in 41% of children (adults 16%), while a high creatine phosphokinase was seen in 31% of children compared with 17% of adults. CONCLUSIONS: Children seem to have more serious local and systemic complications than adults and this may indicate the need to use a higher dose of antivenom than that being used at present. (+info)
Histologic and functional renal alterations caused by Bothrops moojeni snake venom in rats.
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Acute renal failure (ARF) is the main cause of death following snake bites by Bothrops species. In this study, we investigated the morphologic and functional renal disturbances caused by Bothrops moojeni venom in rats. Renal function was assessed based on creatinine and lithium clearances and on histologic examination of renal tissue 5 hr after the intravenous administration of 0.2 mg of venom/kg and 5 hr, 16 hr, and 48 hr after 0.4 mg of venom/ kg. A venom dose of 0.4 mg/kg produced renal tubule disturbances, including acute impairment of proximal and post-proximal tubule sodium handling associated with acute tubule necrosis. The glomerular filtration rate (GFR) decreased significantly and was accompanied by severe morphologic disturbances in the renal glomeruli. These functional and morphologic findings were observed in the absence of any change in mean arterial blood pressure. The decrease in GFR was not related to the presence of fibrin deposits in the glomerular capillary loops. These results suggest an early nephrotoxic action of B. moojeni venom involving significant morphologic and functional changes similar to those observed in snakebite-induced ARF in humans. (+info)
Short report: treatment of snake envenomations by a new polyvalent antivenom composed of highly purified F(ab)2: results of a clinical trial in northern Cameroon.
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A clinical trial was conducted in 2 health centers in northern Cameroon to assess the safety and efficacy of a new polyvalent antivenom composed of highly purified and pasteurized F(ab')2 (FAV-Africa). Forty-six patients with objective signs of envenomation, including 67% with hemorrhage, were included in the study. Each patient received at least 20 ml of FAV-Africa by direct, slow intravenous injection; 172 10-ml ampules were administered. All patients were clinically cured after treatment. Two patients (4.3%) showed minor immediate adverse events that may have been related to FAV-Africa (induration, light-headedness); no other treatment-related adverse event occurred. No patient had serum sickness. This trial confirms the safety of FAV-Africa administered by intravenous injection and its efficacy in the treatment of snake envenomations in sub-Saharan Africa. (+info)
Cortical blindness: an unusual sequela of snake bite.
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Several ophthalmic effects may follow snake bite; this report describes an instance of cortical blindness that resulted from snake bite. (+info)