Utility of scorpion antivenin vs prazosin in the management of severe Mesobuthus tamulus (Indian red scorpion) envenoming at rural setting.

BACKGROUND Scorpion antivenom (SAV) is specific antidote to scorpion venom..SAV did not prevent the cardiovascular morbidity and mortality (autonomic storm), hence its utility in the management for severe scorpion envenomingmay be limited. Since 1983 the advent of prazosin revolutionized the management of severe scorpion sting. Since 2002 SAV against Indian red scorpion (IRS) for the treatment of scorpion sting cases is available at primary health centers. We compared the effects of SAV Vs Prazosin (PRA) in the management of severe scorpion stung cases at rural setting in a non-randomised open label manner. METHODS From January 2002 to December 2004, 53 patients accidentally stung by scorpion were admitted in hospital at Mahad. Of these 25 patients received intravenous SAV at primary health centers and were referred to Mahad for further management. 28 patients directly reported to Mahad were treated with oral prazosin (PRA). Time interval between sting and hospitalization, the total dose of SAV and PRA administered was noted. Clinical manifestations were noted in a standard protocol. Details of SAV patients were noted from referred letters or in case of a doubt, details were obtained by direct communication with the medical officer who first saw and examined the case. All 53 cases were evaluated clinically for improvement, deterioration or fatal outcome. RESULTS SAV Vs PRA ( 25 Vs 28) cases reported to hospital within 11/2 -3 (1.4) Vs 1/2-4 (1.3) hours after stung. On arrival 21 (84%) Vs 26 (92%) had hypertension, 2 (8%) Vs 1 (3.5%) had hypotension, 2 (8%)Vs 1 (3.5%) had normal blood pressure. Heart rate 58-102 (82) Vs 48-120 (80.2) respectively. 9 cases received 20 ml, 1 case 30 ml and remaining 15 cases were given 10 ML of SAV on arrival to PHC, while 28 cases received oral prazosin. 20 (80%) Vs 2 (7.5%) had acute pulmonary edema, 5 (20%) Vs 8 (30%) had persistent raised blood pressure. 4 (16%) Vs 0% died. Recovery time was 11-4 (2.26) Vs 1-2 (1.25) days respectively. CONCLUSION We found that SAV is no more effective to alleviate or reverse the cardiovascular effects of scorpion venom actions in severe case as against prazosin prevents and cures the cardiovascular manifestations in a severe scorpion envenomation. Therefore role of SAV in severe scorpoin venomation needs to be relooked and prazosin needs to be a standard of care in such cases to overcome the autonomic storm.