Razi Vaccine & Serum Research Institute
Scorpionism is a known significant problem of medical and social importance in many tropical and subtropical regions including the Middle East. In Iran, highest prevalence of scorpion sting about 60% of all the stings has been reported from Khuzestan province. Among the 21,000 cases of reported scorpion stung patients, 12% were caused by H. lepturus, but contributed to 95% of all moralities in scorpion stung patients. The sting of H. lepturus does not produce an immediate pain as does the sting of other scorpions, rather cause delayed swelling that may diffuse and is often accompanied by late necrosis at the sting site suggestive of less significant role of the nervous system stimulation. Since the venom from H. lepturus is cytotoxic in nature and the renal response and blood toxicity are normally simultaneously manifested, it is suggested that the toxin binds to kidney tissue and potentially induce acute renal failure in stung patients. Pharmacokinetic analysis revealed that Intramuscular) i.m) injection of antivenoms is ineffective in neutralizing the action of venoms. Although some reports mention the slow distribution rate of H. lepturus venom following sting, but since the cytotoxic effect of venom from this scorpion is irreversible by antivenom once it occurs, it is recommended to use antivenom through intravascular (i.v) route. Antivenoms of F(ab)2 fraction are the best choice of treatment for their fast extravasation, their ample distribution into the extracellular space, and their prolonged retention time.