[Clinical evolution and circulating venom levels in scorpion envenomations in Morocco]

We conducted a clinical and biological study in Morocco in order to assess the efficacy of antivenom therapy against scorpion stings. Epidemiological and clinical data were collected in 275 patients envenomed by Androctonus mauretanicus mauretanicus and Buthus occitanus scorpions. Patients received antivenom or symptomatic drugs. Blood samples were collected upon hospital admission, at 1 hr and 3 hrs after the treatment. An enzyme linked immunosorbent assay (ELISA) was set up to quantify the venom levels in serum of envenomed patients. Mean serum venom concentrations showed an association between clinical signs and the venom level. The venom concentration at admission, in patients who received 10 ml of antivenom, was significantly reduced after antivenom therapy. The decrease was less important in patients who received only 2 to 5 ml of antivenom. No difference was shown in the venom concentration of patients not treated with antivenom. The clinical signs decreased significantly after antivenom treatment. The absence of antivenom administration increased the risk to develop clinical signs at the end of hospitalisation. This risk was much higher when the delay between scorpion sting and hospital admission increased. The results of our study have demonstrated the efficacy of antivenom in reducing circulating venom and symptoms. Antivenom therapy is more efficient when administered as soon as possible after envenomation and with appropriate quantities of antivenom. This study is favourable to the use of SAS but a prospective study would be useful to confirm these data.