TIME FACTOR IN THE DETECTION OF CIRCULATING WHOLE VENOM AND CROTOXIN AND EFFICACY OF ANTIVENOM THERAPY IN PATIENTS ENVENOMED BY CROTALUS-DURISSUS

Thirty-seven patients envenomed by Crotalus durissus were classified i nto three groups according to the interval between the bite and hospit al admission (Delta T): group I (It = 14, Delta T < 4 hr), group 2 (n = 14, Delta T > 4 hr < 8 hr) and group 3 (n = 9, Delta T > 8 hr). Veno us blood from these patients was sampled for biochemical and hematolog ical analysis and for whole venom, crotoxin and antivenom enzyme-linke d immunosorbent assays before antivenom treatment (TO) and at 1 hr (T1 ), 6 hr (T6), 12 hr (T12) and 24 hr (T24) after the start of antivenom therapy. The patients were treated with 100-200 mi (10-20 ampules) of C. durissus antivenom. Whole venom and crotoxin were detected in 13 ( 92.8%) and 11 (78.6%) of 14 group 1 patients, respectively, in 11 (78. 6%) and six (42.9%) of 14 group 2 patients, respectively, and in two ( 22.2%) and one (11.1%) of nine group 3 patients, respectively, before antivenom treatment. Data from this study show that whole venom and cr otoxin were not detected in most of patients when the time elapsed bet ween the bite and hospital admission was greater than 8 hr, and crotox in was not detected in most of the patients who were admitted to the h ospital at times ranging from 4 to 8 hr after the snakebite. Plasma wh ole venom, crotoxin and antivenom levels measured over time in these p atients show the efficacy of antivenom treatment, since circulating ve nom and crotoxin were no longer detected 1 hr after antivenom therapy and high antivenom titers persisted for at least 24 hr after serothera py. (C) 1997 Elsevier Science Ltd.