Snake bite and antivenom complications in Belo Horizonte, Brazil

Factors associated with clinical complications of snake bite and antivenom therapy were studied in 310 hospital patients admitted with snake bite over 6 years to a tertiary referral hospital in Belo Horizonte, southeast Brazil. Overall, 17.4% had early clinical complications including tissue loss associated with abscess and necrosis, acute renal failure, shock, acute lung oedema and intracranial haemorrhage. 3% had permanent sequelae, caused by muscle contractures and amputations, chronic renal failure, or death. Early complications were associated with the following: age under 9 years (P = 0.04), residence in a rural area (P = 0.04), and a delay of more than 8 h in seeking clinical care (P < 0.01). Antivenom was administered to 98.1% of patients; 13.8% presented with anaphylaxis and 11.8% with pyrexia. Individuals from a rural area had a higher occurrence of anaphylactic reactions (P = 0.03). Neither anaphylaxis nor pyrexia was linked with antivenom type and dosage. This study suggested that antivenom might be associated with a reduced risk of serious injuries related to snake bite, especially when administered within the first 8 h. Complications appeared to be a far greater risk than adverse reactions to the antivenom.