João Luiz Costa Cardoso

A clinical and epidemiological study of Loxosceles spider envenoming in Santa Catarina, Brazil

A clinical and epidemiological study of 267 cases of envenomation by Loxosceles spp. (loxoscelism), notified to Centro de Informações Toxicológicas de Florianópolis (Santa Catarina State, Brazil), was conducted between January 1985 and December 1995. Most of the incidents occurred along the coast of the mid-southern region of the state, during the warmest months. L. laeta and L. intermedia were identified as the causative agents. Cutaneous loxoscelism was clinically diagnosed in 232 (86.9%) patients with local pain (86.5%), oedema (80.5%), hyperaemia (79.8%) and necrosis (56.9%). Cutaneous-visceral loxoscelism was detected in 35 patients (13.1%) with intravascular haemolysis, manifested by jaundice (68.6%), oliguria (45.7%), dark urine (28.6%), haemorrhage (25.7%), anuria (8.6%) and shock (2.9%), besides the cutaneous effects. Specific antivenom was given to 125 patients (46.8%) and only 8 (6.5%) had mild reactions. Acute renal failure was observed in 17 cases (6.4%); 4 patients (1.5%) died, all of whom were children under 14 years old.

Clinical trial of two antivenoms for the treatment of Bothrops and Lachesis bites in the north eastern Amazon region of Brazil

The efficacies of specific Bothrops atrox-Lachesis and standard Bothrops-Lachesis antivenoms were compared in the north eastern Amazon region of Brazil. The main aim was to investigate whether a specific antivenom raised against the venom of B. atrox, the most important Amazon snake species from a medical point of view, was necessary for the treatment of patients in this region. Seventy-four patients with local and systemic effects of envenoming by Bothrops or Lachesis snakes were randomly allocated to receive either specific (n = 38) or standard (n = 36) antivenoms. In 46 cases (24 in the standard antivenom group, 22 in the other) the snake was identified either by enzyme immunoassay or by examination of the dead snake, as B. atrox in 45, L. muta in one. Patients were similar in all clinical and epidemiological respects before treatment. Results indicated that both antivenoms were equally effective in reversing all signs of envenoming detected both clinically and in the laboratory. Venom-induced haemostatic abnormalities were resolved within 24 h after the start of antivenom therapy in most patients. The extent of local complications, such as local skin necrosis and secondary infection, was similar in both groups. There were no deaths. The incidence of early anaphylactic reactions was 18% and 19%, respectively for specific and standard antivenoms; none was life-threatening. Measurement of serum venom concentrations by enzyme immunoassay (EIA) confirmed that both antivenoms cleared venom antigenaemia effectively. EIA also revealed that one patient had been bitten by Lachesis muta, although the clinical features in this case were not distinctive.

Coagulopathy and haemorrhage in human victims of Bothrops jararaca envenoming in Brazil

Thirty-four patients envenomed by Bothrops jararaca in Brazil were studied. Of these, 20 (59%) had incoagulable blood associated with local and/or systemic bleeding and 10 of the 20 were thrombocytopenic. Among 14 patients with coagulable blood, 6 (43%) had bleeding symptoms and 3 (21%) were thrombocytopenic. High levels of von Willebrand factor (vWF), plasminogen activator inhibitor type 1 (PAI-1) and tissue type plasminogen activator (t-PA) antigens were also recorded in some patients with systemic bleeding with or without incoagulable blood. These substances may have been released from endothelial cells. Admission serum venom antigen levels were similar in both groups. The study indicated that systemic haemorrhage may occur in patients with coagulable blood and thrombocytopenia and that coagulopathy is not therefore the primary cause of haemorrhage.

A report of 49 cases of cnidarian envenoming from southeastern Brazilian coastal waters

Forty-nine accidents caused by jellyfish (Cnidaria) were observed during a period of 5 years on the southeastern coast of Brazil. Most of them involved male patients (65.3%), the injured areas being mainly the legs (71.3%) and the trunk (65.3%). Twenty accidents with Chiropsalmus quadrumanus, four with Physalia physalis and 20 with unidentified jellyfish presented intense pain, linear plaques and systemic symptoms. The five cases with Olindias sambaquiensis caused mild pain, round plaques and no systemic symptoms. There are a few reports on accidents caused by jellyfish, in this country, and scarce clinical or epidemiological data are available up to the present moment.

Sequential randomised and double blind trial of promethazine prophylaxis against early anaphylactic reactions to antivenom for bothrops snake bites

Abstract 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, São 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. Key messages Antivenom therapy may cause early anaphylactic reactions Various drugs are used to prevent reactions, but none have been tested in randomised controlled studies This study showed that promethazine is not better than placebo at preventing early reactions Although most reactions are mild or moderate, trials of other drugs should be done to reduce frequency of anaphylaxis

Clinical and epidemiological features of definitive and presumed loxoscelism in São Paulo, Brazil

A retrospective study analysed 359 proven or presume cases of loxoscelism seen at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, between 1985 and 1996. The spider was identified in 14%. The bites occurred predominantly in the urban areas (73%) between September and February. Patients > 14 years were commonest inflicted (92%) and 41% were bitten while getting dressed. Only 11% sought medical care within the first 12 hours post bite. Cutaneous loxoscelism was the commonest form presenting (96%); commonest manifestations were: pain (76%), erythema (72%), edema with enduration (66%), ecchymosis (39%). Skin necrosis occurred in 53% of patients, most frequently seen on trunk, thigh and upper arm, and when patients seek medical care more than 72 hours after bite. Local infection was detected in 12 patients (3%). Hemolysis was confirmed in 4 cases (1.1%). Generalised cutaneous rash, fever and headache were also observed in 48% of the total of patients. None of them had acute renal failure or died. Treatment usually involved antivenom administration (66%), being associated with corticosteroids (47%) or dapsone (30%). Presumptive diagnosis of loxoscelism may be established based on clinical and epidemiological findings. Further investigations are required to prove the value of antivenom and other treatment schedules.

Toxic activities of venoms from nine Bothrops species and their correlation with lethality and necrosis.

The comparison of seven toxic activities contained in venoms from nine different species of Bothrops and the correlation of each activity with lethality and necrosis was the subject of this study. The haemorrhagic, coagulant, necrotizing, myotoxic, proteolytic and phospholipase activities were not equally distributed among the venoms studied except for the oedema-inducing activity which was almost equally distributed among them. The correlation coefficient was estimated for each activity in relation to lethality and necrosis induced by the venom. Lethality was significantly related to haemorrhagic and oedema-inducing activities, whereas the necrotizing activity showed significant correlation with phospholipase and coagulant activities. Proteolytic activity presented a significant inverse correlation with lethality.

Haemostatic changes caused by the venoms of south american snakes

Changes in the haemostatic mechanism caused by venoms of Bothrops, Crotalus and Lachesis snakes from Central and South America in human accidents are reviewed. Changes in the blood coagulation mechanism could be found depending on the action of the venom on clotting factors.

Dermonecrotic and lethal components of Loxosceles gaucho spider venom

Loxosceles gaucho spider venom causes a typical dermonecrotic lesion in bitten patients and rarely causes lethal systemic effects. Gel filtration on Sephadex G 100 of L. gaucho spider venom resulted in three fractions: fraction A, containing the higher mol. wt components (approximately 35,000); fraction B, containing lower mol. wt components (approximately 15,000); and fraction C, containing very low mol. wt components (probably small peptides). The dermonecrotic and lethal activities were detected exclusively in fraction A. The venom and fraction A produced large dermonecrotic lesions in rabbits with necrosis spreading by gravity to the skin of the lateral body wall. Analysis by SDS-PAGE showed that the proteins contained in fraction A are approximately 35,000 and 33,000 mol. wt. Immunoblotting analysis showed that the proteins responsible for the dermonecrotic and lethal activity are very immunogenic and the first to be detected by antibodies during the course of immunization.

Platelet aggregation in patients bitten by the Brazilian snake Bothrops jararaca.

Patients bitten by the lancehead snake Bothrops jararaca usually develop systemic bleeding. Our aim was to evaluate platelet function in whole blood of 17 human patients bitten by this snake in São Paulo State, Brazil. Bleeding occurred in 71% of these patients, and thrombocytopenia in 53% of them. On admission, most of the patients presented with hypoaggregation to 50 microM ADP and 1.2 mg/ml ristocetin, and only 35% of them to 5 micrograms/ml collagen. Abnormal plasma levels of fibrinogen and fibrin(ogen) degradation products (FDP/fdp) were also observed. Twenty-four hours of finishing serumtherapy, bleeding had already ceased, fibrinogen and FDP/fdp levels returned to hemostatic levels, and values for platelet aggregation returned to the reference range of controls, except for ADP that still remained decreased. These findings evidence that disturbances of platelet function are also an important factor for the development of bleeding in Bothrops envenomation, as well as other known hemostatic disturbances that occur concomitantly.