Risk factors for fatal scorpion envenoming among Brazilian children: a case-control study

Background: Scorpion envenoming is relatively frequent in tropical and subtropical regions and potentially fatal. We aimed to identify risk factors for fatal scorpion envenoming among Brazilian children. Methods: A case-control study investigated all fatal cases of scorpion envenoming among children up to 10 y old, reported to the Brazilian Diseases Surveillance System between 1 January 2007 and 18 July 2016. Controls were randomly sampled from children who survived the envenoming over this period. Data were analysed using logistic regression. Results: Of the 254 cases and 1083 controls investigated, the identified risk factors were age <= 5 y, occurred in a rural area, time-to-treatment >= 3 h, treatment with scorpion antivenom (SAV) but either excessive or insufficient number of vials, treatment with antivenom that was neither SAV nor anti-spider and no antivenom administered compared with the standard recommended treatment. Treatment effectiveness at preventing fatal scorpion envenoming was 77.0% when time-to-treatment was <3 h and 75% in children 9-10 y of age. SAV was 63% effective at preventing death when administered early at the recommended dosage. Conclusions: Fatal scorpion envenoming was associated with younger age, incident occurring in a rural area, late treatment and inadequate antivenom treatment. SAV was effective at preventing death when administered early.