Ensaio clinico para avaliação da eficacia e segurança de um antiveneno especifico no tratamento da sindrome hemorragica causada por lagartas do genero Lonomia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

A clinical trial to evaluate the efficacy and safety of a specific antivenom against the hemorrhagic syndrome caused by Lonomia caterpillars. Disseminated bleeding after the contact with caterpillars was first described in Brazil in 1912. In Venezuela, a hemorrhagic syndrome caused by larvae ofa moth ofthe Satuniidae family, namely, Lonomia achelous, has been reported since the 1960 s, and similar cases were also reported in Amazon region. At the end of the eighties, a very high incidence of the bleeding syndrome has been described in the rural areas in the south of Brazil and the caterpillars were identified as Lonomia oblíqua. Patients experienced burning pain at the site of contact, followed by general discornfort, headache and nausea, and in some hours afier contact, hemorrhagic manifestations: bleeding from skin and mucous membranes, epistaxis, hematuria, hematemesis, pulmonary bleeding. Acute renal failure and intracerebral bleeding were associated with fatal outcomes. In a short time, due to severity and progression of cases, Lonomia caterpillar envenoming was therefore considered a new public health problem. As antivenoms are effective therapy for treatment of snake bites, a process of manufacturing a specific Lonomia antivenom (SALon) was developed by immunizing horses with Lonomia caterpillar bristle extracts. The safety and efficacy of this new antivenom has been tested in a three phase randomized open c1inicaltrial at the Hospital São Vicente de Paulo, Passo Fundo, RS. In phase I, 15 patients received different amounts of SALon and three presented anaphylactic/anaphylactoid reactions (urticaria in two and brochospasm in one). Frequency and severity of early reactions were not exceptionally different in either ofthe next phases, confirming its safety. Patients in phase II, graded according to severity of envenoming, were allocated in two groups: SALon or epsilon-amino-caproic acid (EACA), an antillbrinolytic drug extensively used in Lonomia cases in Venezuela. The study was interrupted when a patient in group EACA died 64 days afier hospitalization in consequence of acute renal failure and infectious complications. At that time, 9 patients had received SALon and 8 EACA. The comparison showed an evident superiority of SALon in reversing the consumptive coagulopathy, measured by Coagulation Test, Prothrombin Time and dosage of plasma fibrinogen. The decision was not to deprive any patient of antivenom therapy and, in phase III, the efficacy of the association between SALon with EACA was assayed. Patients receiving SALon (n = 58) or SALon + EACA (n = 56) showed to be similar in terms the time needed to normalize coagulation parameters, which occurred within 24 hours afier antivenom therapy in most of patients. The sequential reanalysis of data, applying the triangular test, gave a substantial reduction in the number of patients required, for the same conclusions reached with the completed study. The trial was fmished concluding that antivenom is efficacy in the treatment of Lonomia caterpillar envenoming and there is no advantage to be used in association with EACA

ASSUNTO(S)

doenças hemorragicas antivenenos analise sequencial lagarta

ACESSO AO ARTIGO

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