Department of Pediatric Medicine, Institute of Post Graduate Medical Education and Research, Kolkata,
West Bengal, India.
Email: [email protected] 
 

We read the recently published article [1] on the effectiveness of scorpion antivenom in children with interest. The authors of the article state that "there are no exclusive studies on scorpion antivenom in pediatric patients". In this context, we would like to share our experience with the usage of scorpion antivenom and update the readers of Indian Pediatrics. In a recently published randomized controlled trial conducted by us [2], we assessed the efficacy of scorpion antivenom plus prazosin (n=25) versus prazosin alone (n=25) for clinical grade 2 Mesobuthus tamulus scorpion sting enveno-mation [3] in children. The trial demonstrated beneficial effects of scorpion antivenom in the form of significant reduction in the mean time required for complete resolution of autonomic symptoms (sweating, salivation, priapism and cold peripheries), reduction in the proportion of children deteriorating to more severe clinical grades of envenomation [3], lesser doses of prazosin requirement and fewer days of hospital stay. Scorpion antivenom was beneficial even when given upto 8 hours after the sting possibly due to redistribution of venom from the tissues to the plasma. Scorpion antivenom usage also led to decreased incidence of myocardial dysfunction. No serious adverse effects of scorpion antivenom were encountered.

While the case control study by Pandurang, et al. [1] too demonstrated beneficial effects as well as safety of scorpion antivenom, we have some concerns regarding the study. The incidence of various autonomic symptoms and their resolution time is not stated. We also do not find mention of other clinical parameters such as the proportion of children deteriorating to more severe clinical symptoms such as myocarditis or pulmonary edema, and mean doses of prazosin requirement in both the groups. These parameters are important in order to assess the efficacy of scorpion antivenom. Data regarding electrocardiogram and echocardiography, which are essential tools for the optimum management of children with scorpion sting envenomation developing myocardial dysfunction, have not been presented.

A high mortality (11.2%) in the subjects enrolled by Pandurang, et al. [1] is also a concern. Prazosin alone has been known to reduce the mortality to less than 1 % [4]. A lesser dose (only one vial injected over 5-7 minutes) of anti-scorpion venom and high incidence of pulmonary edema could have contributed to the high mortality. We also wish to point out that test doses of scorpion antivenom may not be essential for this condition as anaphylaxis is rare due to the high levels of adrenaline associated with scorpion sting envenomation [2-5].

1. Pandurang KS, Singh J, Bijesh S, Singh HP. Effectiveness of anti scorpion venom for red scorpion envenomation. Indian Pediatr. 2014;51:131-3.

2. Pandi K, Krishnamurthy S, Srinivasaraghavan R, Mahadevan S. Efficacy of scorpion antivenom plus prazosin versus prazosin alone for Mesobuthus tamulus scorpion sting envenomation in children: a randomised controlled trial. Arch Dis Child. 2014;99:575-80.

3. Bawaskar HS, Bawaskar PH. Efficacy and safety of scorpion antivenom plus prazosin compared with prazosin alone for venomous scorpion (Mesobuthus tamulus) sting: randomised open label clinical trial. BMJ. 2011;342:c7136.

4. Bawaskar HS, Bawaskar PH. Envenoming by scorpions and snakes, their neurotoxins and therapeutics. Trop Doct. 2000;30:23-5.