Table 2 Characteristics of included studies for meta-analyses
Studies and parameters | Comments |
|---|---|
Comparison | Antivenom vs. standard therapy (new world scorpions) |
Boyer et al. 2009 [20] | |
Methods | Randomized double blind study |
Participants | Children and adults aged between 6 months and 18 years admitted to a paediatric intensive care unit within 5 h since a scorpion sting |
Interventions | The test group (n = 8) received scorpion antivenom against Centruroides sp. while the control group (n = 7) received a placebo. Dose: three vials diluted in 50 ml of saline. Both groups received similar supportive care. |
Outcomes | Resolution of clinical syndrome within 4 h of antivenom administration, cumulative midazolam dose required for sedation and serum venom levels up to 4 h post admission, adverse events |
Study location | Arizona, USA |
Boyer et al. 2013 [19] | |
Methods | Controlled study with trial arm recruited prospectively and compared with a retrospective control group |
Participants | Children and adults aged between 6 months and 18 years admitted to a paediatric intensive care unit within 5 h since a scorpion sting |
Interventions | The prospectively recruited subjects (n = 78) received scorpion antivenom against Centruroides sp. while the control group (n = 97) had been managed without antivenom. Three vials of antivenom were administered within 10 min diluted in 50 ml of saline. Two additional vials were administered at the discretion of the physician if symptoms had not resolved at 1 or 2 h since the initial dose. |
Outcomes | Resolution of clinical syndrome within 4 h of antivenom administration, serum venom levels up to 4 h post admission (in prospective group only), adverse events |
Study location | Arizona, USA and Morelos, Mexico |
LoVecchio et al. 2003 [18] | |
Methods | Observational study without randomization |
Participants | Children aged less than 2 years with either a witnessed scorpion sting or signs and symptoms consistent with scorpion envenoming |
Interventions | Severity was graded on a scale of I–IV with grades III and IV having systemic envenoming. A subset of patients with grade III and IV envenoming had received anti-Centruroides antivenom (1 vial diluted in 50 ml of saline, n = 86). Another 46 children did not receive antivenom despite having grade III and IV envenoming. Criteria for administration of antivenom are not clear. |
Outcomes | Meantime for resolution/improvement of systemic envenoming, adverse events, deaths |
Study location | Arizona, USA |
Comparison | Antivenom vs. standard therapy (old world scorpions) |
Abroug et al. 1999 [15] | |
Methods | Prospective randomized controlled trial |
Participants | Patients with scorpion stings older than 10 years. A total of 825 patients were randomly allocated to test (n = 412) and control arms (n = 413) |
Interventions | The test group received 20 ml of bivalent (A. australis and B. occitanus) scorpion antivenom. Both groups received supportive care with steroids, fluid replacement, antihistamines and life-supporting measures for systemic envenoming as required. |
Outcomes | Severity was graded as I (no systemic envenoming) and II (systemic envenoming). Prevention was defined as non-progression from grade I to II, and cure was defined as reversal of symptoms from grade II. Outcomes were defined after 4 h since administration of antivenom or admission. Other monitored outcomes were death, complications of envenoming and adverse effects attributable to antivenom. |
Study location | Tunisia |
Belghith et al. 1999 [16] | |
Methods | Retrospective analysis of a sub-population of patients enrolled for a clinical trial. Control group selected prospectively |
Participants | Patients with scorpion stings older than 10 years. One hundred and thirty five patients who were administered bivalent antivenom for scorpion during a previous trial had their records re-examined and matched with controls on a pair-match basis. |
Interventions | No prospective intervention. Controls did not receive antivenom. |
Outcomes | Severity was graded as I (no systemic envenoming) and II (systemic envenoming). Prevention was defined as non-progression from grade I to II, and cure was defined as reversal of symptoms from grade II. Outcomes were defined after 4 h since administration of antivenom or admission. Other monitored outcomes were death, complications of envenoming and adverse effects attributable to antivenom. |
Study location | Tunisia |
Comparison | Antivenom plus prazosin vs. prazosin |
Bawaskar et al. 2011 [23] | |
Methods | Randomised open label clinical trial |
Participants | Patients older than 6 months, reporting to hospital within 6 h of the sting and of grade II clinical severity (systemic autonomic symptoms without shock). A total of 70 patients were randomized, 35 each to test and control groups. |
Interventions | The test group received Haffkine Biopharma monovalent scorpion antivenom (against M. tamulus) 30 ml dissolved in 100 ml of normal saline and infused over 30 min. Both groups received either 250 μg (under 18 years of age) or 500 μg of oral prazosin at 3 hourly intervals until the extremities were cold (resolution of peripheral vasodilatation). |
Outcomes | Primary endpoint: resolution of grade II clinical syndrome at 10 h and prevention of progression to a higher grade (III, IV characterized by autonomic symptoms plus shock, pulmonary oedema) Secondary endpoints: time to total resolution of clinical syndrome, total dose of prazosin required within 10 h and adverse events |
Study location | Maharashtra, India |
Natu et al. 2010 [22] | |
Methods | Prospective open label clinical trial |
Participants | Patients aged 12–70 with a confirmed scorpion sting. The authors developed a composite clinical score based (minimum and maximum scores were 0 and 25, respectively) on pulse rate, blood pressure, presence of priapism, sweating, pain and neurological symptoms. Scores between 5 and 21 were included in the study. The enrolled were randomized into three trial arms: prazosin alone (n = 25), prazosin and antivenom (n = 28) and antivenom alone (n = 28). |
Interventions | Haffkine monovalent antivenom was administered dissolved in distilled water (1:1) over 5–7 min intravenously. The total dose of antivenom was decided based on composite clinical score and patient’s age. The doses varied between 20 and 80 ml. Prazosin was administered orally at 3 hourly intervals at a dose of 500 μg (<20 kg body wt) or 1 mg (>20 kg body wt). |
Outcomes | Primary endpoint: time to resolution of clinical symptoms |
Study location | Maharashtra, India |
Pandi et al. 2014 [24] | |
Methods | Randomized controlled trial |
Participants | Children aged less than 13 years were randomized into test (n = 25) and control (n = 25) groups. Grading of severity of sting was as according to Bawaskar et al. |
Interventions | The test group received monovalent Haffkine antivenom according to protocol described by Bawaskar et al. Both groups received prazosin at a dose of 30 μg/kg/dose at 3 hourly intervals until resolution of the clinical syndrome. |
Outcomes | Primary endpoint: time to resolution of clinical syndrome Secondary endpoints: total dose of prazosin required, adverse events, prevention of worsening of clinical syndrome and duration of hospital stay |
Study location | Pondicherry, India |