Serotherapy in scorpion envenomation: a randomised controlled trial.

BACKGROUND: Evidence for the benefit of scorpion antivenom, the only specific treatment for scorpion envenomation, is scarce, despite its common use. We did a prospective, randomised, controlled trial to assess the efficacy of routine administration of scorpion antivenom to scorpion-stung patients, irrespective of clinical severity. METHODS: We included 825 consecutive patients older than 10 years, who presented to the accident and emergency department of the hospital in Tozeur, Tunisia. We graded severity by absence (grade I) or presence (grade II) of systemic manifestations of scorpion envenomation. Patients were randomly assigned placebo (n=413) or 20 mL bivalent intraveneous scorpion antivenom (n=412). All patients were observed for 4 h. Patients who developed life-threatening symptoms were admitted to the intensive-care unit. At the end of 4 h observation we reassessed grade and discharged grade II patients and admitted grade II patients. We assessed the preventive and curative effects of scorpion antivenom by prevention of worsening grade or by improvement from grade II to grade I. FINDINGS: Distribution of severity grades was similar in the two groups at baseline, as were the cure rates (55% scorpion antivenom, 66% placebo, absolute difference, 11% [95% CI -4.8 to 26.8]; p=0.234). Preventive effects were seen in 94% and 96% of patients in the scorpion antivenom and placebo groups, respectively, who were initially grade I and who remained symptom-free (absolute difference, 2% [-1.27 to 5.27]; p=0.377). Time from scorpion sting to administration of scorpion antivenom did not affect curative and preventive effects. INTERPRETATION: We found no benefit in routine administration of scorpion antivenom after scorpion sting, irrespective of clinical severity. Future studies should focus on patients with the most severe symptoms and signs.

Efficacy of serotherapy in scorpion sting: a matched-pair study.

BACKGROUND/OBJECTIVE: Although evidence of scorpion antivenin effectiveness in the clinical setting is lacking, scorpion antivenin is generally considered the only specific treatment for scorpion sting irrespective of its clinical severity. We conducted a matched-pair study to assess the efficacy of systematic administration of scorpion antivenin. METHODS: Among 600 stung patients who participated in a study on the efficacy of high-dose hydrocortisone after scorpion sting, 135 (cases) had been treated with 10 to 20 mL intravenous scorpion antivenin (neutralizing 10 LD50 venom/mL). Controls were matched on disease severity on arrival to the emergency department. The severity of envenomation was graded I or II according to the absence (grade I) or the presence (grade II) of systemic manifestations of scorpion envenomation. Assessment of scorpion antivenin efficacy was based on the rate of changing severity grade in both groups (clinical improvement or worsening during an observation period of at least 4 hours). RESULTS: Both groups were similar with respect to clinical severity (36 patients were graded II in each group), age, sex, time-lapse between scorpion sting and ED arrival, and the administration of adjunctive therapy such as hydrocortisone. By the 4-hour evaluation, 50% and 64% of patients initially graded II exhibited a substantial clinical improvement in cases and controls, respectively, suggesting similar effects in cases and controls. There was no difference in preventive effects: 13% and 10% of cases and controls developed systemic manifestations of scorpion envenomation during the 4-hour observation period; 23% of cases and 17% controls were hospitalized by this time. There was no difference in the duration of hospitalization. Three cases developed anaphylactic shock as a consequence of scorpion antivenin administration, while 1 scorpion antivenin-untreated patient died from refractory shock. CONCLUSION: Systematic administration of scorpion antivenin irrespective of clinical severity did not alter the clinical course of scorpion sting. A prospective study is needed concerning the response of the more severe scorpion envenomations.

High-dose hydrocortisone hemisuccinate in scorpion envenomation.

STUDY OBJECTIVE: Scorpion envenomation is a common life-threatening hazard in tropical and subtropical countries. Standard treatment is not clearly defined. Many therapies, such as steroids, are prescribed without experimental justification. We sought to assess the efficacy of systematic administration of intravenous hydrocortisone hemisuccinate (50 mg/kg) in scorpion envenomation. METHODS: Six hundred consecutive envenomated patients older than 10 years who presented to the ED of a nonteaching secondary hospital in an area of Tunisia endemic for scorpion envenomation were randomly assigned to receive hydrocortisone hemisuccinate 50 mg/kg (n = 305) or placebo (n = 295) in addition to standard medical care. Patients in the two groups had similar clinical characteristics on initial clinical evaluation. Each was categorized as grade 1 (absence of systemic symptoms) or grade 2 (systemic symptoms of scorpion envenomation). Patients were treated in the ED for up to 4 hours or in the ICU, depending on clinical severity. Steroid and placebo groups were compared according to mortality rate, change of severity grade 4 hours after presentation and treatment, and duration of hospital stay. RESULTS: Distribution of patients with respect to severity grade was similar in the two groups at the 4-hour clinical evaluation. We detected no significant difference at the time of discharge between steroid-and placebo-treated patients with respect to mortality (one patient in each group) or duration of hospital stay. Extra costs incurred through steroid administration totaled US $989,000. CONCLUSION: Our findings do not support the use of intravenous high-dose steroids in scorpion-envenomated patients. The discontinuation of this practice would reduce costs substantially.

Right ventricular dysfunction following severe scorpion envenomation.

OBJECTIVE: Evaluation of right ventricular (RV) performance in patients presenting with pulmonary edema following scorpion envenomation. DESIGN: Cohort study. SETTING: Medical intensive care unit of a teaching hospital. PATIENTS: Eight consecutive adult patients stung by yellow scorpion Androctonus australis and presenting with pulmonary edema at hospital admission. INTERVENTIONS: In all patients, standard hemodynamic parameters and RV volumes were measured using a pulmonary artery catheter equipped with a rapid responding thermistor enabling measurement of RV ejection fraction (RVEF). MEASUREMENTS: Hemodynamic evaluation was performed at the time of hospital admission prior to any therapeutic intervention and just before the removal of the pulmonary catheter (2.3 +/- 0.5 days after admission) in the surviving patients (n = 7). RESULTS: All patients had a decreased RVEF (24 +/- 7%) and cardiac index (2.44 +/- 0.5 L/min/m2) and increased pulmonary artery occlusion pressure (23 +/- 6 mm Hg). Right ventricular end-systolic pressure/volume ratio was decreased (.56 +/- .19 mm Hg/mL/m2), suggesting an altered RV contractility. Follow-up evaluation performed in survivors, without any inotropic support, showed hemodynamic changes reflecting a trend toward full recovery. Right ventricular ejection fraction and cardiac index improved markedly (from 24 +/- 7% to 39 +/- 10% and from 2.44 +/- 0.5 to 4 +/- .3 L/min/m2, respectively). Pulmonary artery occlusion pressure, peak systolic pulmonary artery pressure, and mean pulmonary artery pressure decreased significantly from baseline values (12 +/- 3 mm Hg, 29 +/- 5 mm Hg, and 20 +/- 4 mm Hg, respectively). Right ventricular end systolic pressure/volume ratio remained almost constant, suggesting that afterload enhancement accounted predominantly for RVEF improvement. CONCLUSION: These data show that RV function impairment is associated with left ventricular dysfunction, suggesting similarities between left ventricular and RV alterations following severe scorpion envenomation providing further arguments to the hypothesis of scorpionic myocarditis.