High-dose hydrocortisone hemisuccinate in scorpion envenomation

Biochemical and Proteomic Characterization, and Pharmacological Insights of Indian Red Scorpion Venom Toxins

The Indian red scorpion (Mesobuthus tamulus) is one of the world's deadliest scorpions, with stings representing a life-threatening medical emergency. This species is distributed throughout the Indian sub-continent, including eastern Pakistan, eastern Nepal, and Sri Lanka. In India, Indian red scorpions are broadly distributed in western Maharashtra, Saurashtra, Kerala, Andhra Pradesh, Tamil Nadu, and Karnataka; however, fatal envenomations have been recorded primarily in the Konkan region of Maharashtra. The Indian red scorpion venom proteome comprises 110 proteins belonging to 13 venom protein families. The significant pharmacological activity is predominantly caused by the low molecular mass non-enzymatic Na+ and K+ ion channel toxins. Other minor toxins comprise 15.6% of the total venom proteome. Indian red scorpion stings induce the release of catecholamine, which leads to pathophysiological abnormalities in the victim. A strong correlation has been observed between venom proteome composition and local (swelling, redness, heat, and regional lymph node involvement) and systemic (tachycardia, mydriasis, hyperglycemia, hypertension, toxic myocarditis, cardiac failure, and pulmonary edema) manifestations. Immediate administration of antivenom is the preferred treatment for Indian red scorpion stings. However, scorpion-specific antivenoms have exhibited poor immunorecognition and neutralization of the low molecular mass toxins. The proteomic analysis also suggests that Indian red scorpion venom is a rich source of pharmacologically active molecules that may be envisaged as drug prototypes. The following review summarizes the progress made towards understanding the venom proteome of the Indian red scorpion and addresses the current understanding of the pathophysiology associated with its sting.

Scorpions and scorpion sting envenoming (scorpionism) in the Arab Countries of the Middle East

The twelve Arab countries of the Middle East are inhabited by 117 species of scorpions of varying medical importance within six families. Scorpion stings are a very common occurrence throughout the region. Twenty-two scorpion species are considered to be dangerously venomous, causing potentially life threatening stings. Accessible literature in English and Arabic on scorpions, scorpion stings and available antivenoms was reviewed to document the scorpion fauna and scorpion stings in each country. Saudi Arabia, Iraq and Jordan report the highest numbers of stings and envenomings. Clinically, the most important toxins in Old World scorpion venoms are α-toxins that target voltage-gated sodium (Na_v) channels at neurotoxin binding site 3, causing sympathetic excitation and the endogenous release of catecholamines that is responsible for transient, but life-threatening myocardial damage. Most victims of scorpion stings suffer severe local pain, but a few, especially children, develop systemic envenoming which, in the case of most Middle Eastern buthid species, such as Androctonus and Leiurus species, is dominated by the cardiovascular and respiratory consequences of hypercatecholinaemic myocarditis. Other syndromes include paralysis (Parabuthus leiosoma), coagulopathy (Nebo hierichonticus and Hemiscorpius species), and local tissue damage, haemolysis and acute kidney injury (H. lepturus). Early antivenom treatment is recommended but its value remains controversial. However, intensive care, with the ancillary use of vasoactive drugs such as prazosin and dobutamine, has proved effective.

Scorpion Sting Management at Tertiary and Secondary Care Emergency Departments

Objectives

We sought to review the management of scorpion stings in tertiary and secondary care emergency departments in Oman and determine physician’s knowledge of management protocols.

Methods

We conducted a retrospective study of all scorpion stings cases seen in Sultan Qaboos University Hospital (SQUH) emergency department (ED) from March 2016 to July 2017. Additionally, we conducted a survey of ED physicians regarding their management of scorpion stings in three different EDs including SQUH.

Results

The total number of scorpion stings seen at SQUH during the study period was 128. Localized pain was seen in 97.7% (n = 125), swelling in 14.8% (n = 19), and local redness in 7.0% (n = 9) of patients. Around 13.0% (n = 17) of patients were found to have systemic symptoms with tachycardia being the most common. Bedside clotting test was done for 11.7% (n = 15) of patients. The most commonly used treatment was local anesthesia (54.7%, n = 70). No patient received scorpion antivenom. In the 89 surveyed physicians the main management method used was analgesia (88.8%, n = 71) followed by local anesthesia (81.1%, n = 65). Most physicians (80.0%, n = 64) believed that local anesthesia was the most effective management. However, 32.5% (n = 26) ordered a whole blood bedside clotting test, 69.2% (n = 18) of which were junior doctors.

Conclusions

Most scorpion sting cases managed in SQUH had local symptoms. Tachycardia was the most common systemic manifestation. Bedside clotting test was not commonly ordered and mainly requested by junior doctors. Local anesthesia infiltration is the recommended management for scorpion sting. Analgesia was the main management followed by local anesthesia.

Severe Troponin I Elevation and Myocardial Dysfunction in a Child with Scorpion Sting

Background  Scorpion sting is a common medical problem and major cause of mortality and morbidity in many countries. The symptoms of envenomation are more severe in the pediatric population. The clinical manifestations of scorpion envenomation appear by activation of sympathetic and parasympathetic nervous system. Envenomation can cause multiorgan dysfunction and death. Case Presentation and Findings  In this case report, we present a pediatric patient from Adana, Southeast Anatolia, with severe scorpion envenomation with Leiurus abdullahbayrami which is an especially dangerous species for children. Severe systolic dysfunction was detected by echocardiography. Troponin I levels elevated significantly and rapidly responded to three doses of antivenom therapy. Conclusion  Early echocardiographic examination is an important procedure for patients with scorpion envenomation. Troponin I is a significant parameter to monitor the degree of cardiac injury. Antivenom therapy is the only recommended specific therapy for children with severe scorpion envenomation due to Leiurus abdullahbayrami . Abnormal echocardiography findings may require repeated doses of scorpion antivenom.

Management of scorpion envenoming: a systematic review and meta-analysis of controlled clinical trials

BACKGROUND

Scorpion stings cause an estimated 3000 deaths per annum worldwide. We conducted a systematic review of all controlled clinical trials related to scorpion sting management.

METHODS

We searched PubMed, EMBASE, Scopus, Web of Science and CINAHL and included controlled prospective clinical trials (randomized or non-randomized). The following interventions were assessed: adults and children with scorpion stings treated with (a) steroids vs. placebo, (b) different methods of pain relief, (c) antivenom vs. supportive treatment, (d) prazosin vs. supportive treatment, (e) antivenom vs. prazosin and (f) antivenom plus prazosin vs. prazosin alone. When trials had comparative outcomes, they were combined in a meta-analysis. Data was analysed with Review Manager 5. Dichotomous data were compared with relative risk (RR), and continuous data were compared with mean differences using a fixed effect model. There is no PROSPERO registration number for this study.

RESULTS

Antivenom against Centruroides sp. are effective in reversing the clinical syndrome faster than no antivenom treatment in children (RR, 0.02; 95% CI, 0.01 to 0.06; 322 participants; three trials). Antivenom (against Mesobuthus tamulus) and prazosin combination is better than prazosin alone for faster resolution of symptoms (mean difference, -12.59 h; 95% CI, -14.01 to -11.17; 173 participants; three trials).

CONCLUSIONS

The polyvalent antivenom against Centruroides sp. in USA/Mexico and the monovalent antivenom against M. tamulus in India are effective for rapid resolution of symptoms. Prazosin is useful as an add-on therapy for M. tamulus stings.

Scorpion-related cardiomyopathy: Clinical characteristics, pathophysiology, and treatment

CONTEXT

Scorpion envenomation is a threat to more than 2 billion people worldwide with an annual sting number exceeding one million. Acute heart failure presenting as cardiogenic shock or pulmonary edema, or both is the most severe presentation of scorpion envenomation accounting for 0.27% lethality rate.

OBJECTIVE

The purpose of this review is to characterize the scorpion-related cardiomyopathy, clarify its pathophysiological mechanisms, and describe potentially useful treatments in this particular context.

METHODS

We searched major databases on observational or interventional studies (whether clinical or experimental) on the cardiorespiratory consequences of scorpion envenomation and their treatment. No limit of age or language was imposed. A critical appraisal of the literature was conducted in order to provide a pathophysiological scheme that reconciles reported patterns of cardiovascular toxicity and hypotheses and assumptions made so far.

RESULTS

Early cardiovascular dysfunction is related to the so-called "vascular phase" of scorpion envenomation, which is related to a profound catecholamine-related vasoconstriction leading to a sharp increase in left ventricular (LV) afterload, thereby impeding LV emptying, and increasing LV filling pressure. Following this vascular phase, a myocardial phase occurs, characterized by a striking alteration in LV contractility (myocardial stunning), low cardiac output, and hypotensive state. The right ventricle involvement is symmetric to that of LV with a profound and reversible alteration in right ventricular performance. This phase is unique in that it is reversible spontaneously or under inotropic treatment. Scorpion myocardiopathy combines the features of takotsubo myocardiopathy (or stress myocardiopathy) which is linked to a massive release in catecholamines leading to myocardial ischemia through coronary vasomotor abnormalities (epicardial coronary spasm and/or increase in coronary microvascular resistance). Treatment of pulmonary edema due to scorpion envenomation follows the same principles as those applied for the treatment of cardiogenic pulmonary edema in general: this begins with oxygen supplementation targeting an oxygen saturation of 92% or more, by oxygen mask, continuous positive airway pressure, noninvasive ventilation, or conventional mechanical ventilation. Dobutamine effectively improves hemodynamic parameters and may reduce mortality in severe scorpion envenomation.

CONCLUSION

Scorpion cardiomyopathy is characterized by a marked and reversible alteration in biventricular performance. Supportive treatment relying on ventilatory support and dobutamine infusion is a bridge toward recovery in the majority of patients.

Toxic exotics

The purpose of this article is to familiarize the reader with the basic venom components, the pathophysiologic responses of envenomated dogs and cats, and some brief treatment guidelines for envenomations by various exotic "pets." Representative toxic species of reptiles, amphibians, and arthropods are included. The growing trend toward the collection of exotic animals by private owners increases the likelihood that veterinarians will face the challenge of treating an exotic envenomation.

A clinical score predicting the need for hospitalization in scorpion envenomation

OBJECTIVE

Predicting complications is a clinical challenge in the assessment of victims of scorpion envenomation (SE). We sought to develop a clinical score to predict need for hospitalization after scorpion sting.

METHODS

We prospectively collected data in patients attending the emergency department after SE in derivation (n = 868) and validation groups (n = 435). A score was derived from a multiple regression analyses using clinical variables as dependent variables and hospitalization as independent variable.

RESULTS

Discrimination power of the constructed score was good (area under the receiver operating characteristic curve, 0.85 and 0.83 in derivation and validation group, respectively). Goodness-of-fit tests indicated that the score performed well in the derivation and the validation groups (P = .88 and P = .67 respectively). The score has a good sensitivity and negative predictive value at cutoff value of 2.

CONCLUSION

Our clinical score could be used for efficient hospital admission decision in patient's victims of SE.

Life-threatening stings, bites, infestations, and parasitic diseases

Bites, stings and infestations can be fatal. Anaphylaxis to vespids and bees can be prevented with immunotherapy. Patients should be referred to an allergist. The acute care and prevention of arthropod injury is discussed below.

A canine study of immunotherapy in scorpion envenomation

OBJECTIVE

To evaluate the effects of scorpion venom and antivenom in experimental envenomation.

DESIGN

Prospective, controlled animal study.

SETTING

University research laboratory

SUBJECTS

Twenty-nine anesthetized and ventilated dogs.

INTERVENTIONS

The first group of animals had venom alone (0.05 mg/kg). Animals from the second group had simultaneous administration of 10 ml of scorpion antivenom (SAV). In the third and fourth groups, 10 ml and 40 ml SAV, respectively, were injected 10 min following venom.

MEASUREMENTS AND RESULTS

Hemodynamic parameters using right heart catheter were recorded and dosage of catecholamines, neuropeptide Y (NPY), endothelin-1, and atrial natriuretic peptide (ANP) were performed at baseline and during 60 min following envenomation. In the control group, at 5 min, there was a sharp increase in pulmonary artery occluded pressure (PAOP, from 2 mmHg to 23 mmHg), mean arterial pressure (MAP, from 125 mmHg to 212 mmHg) and systemic vascular resistance (SVR, from 2450 dyn sec(-1 )m(5) to 5775 dyn sec(-1 )m(5), P<0.05 for all). Heart rate, cardiac output, and stroke volume decreased. There was a 40-fold increase in epinephrine and norepinephrine plasma concentrations. Circulating NPY and ANP dosages increased too. PAOP and MAP decreased thereafter to reach baseline levels. Simultaneous administration of SAV with venom totally offset the hallmarks of scorpion envenomation. Delayed administration of SAV at any dosage failed to alter the features of scorpion envenomation.

CONCLUSION

While simultaneous administration of SAV and scorpion venom is effective in preventing scorpion envenomation-related manifestations, delayed administration of SAV, either at standard or elevated dosages, failed to alter any of the scorpion envenomation features.

Human and animal bites and venomous stings

Human and animal bites and venomous stings demand careful handling. Immediate resuscitation may be necessary. Severe tissue damage from larger animals frequently requires urgent haemorrhage control, followed by debridement. Subsequent reconstruction is commonly necessary. Smaller bites, and particularly human bites, may easily be underestimated, and can have significant infective sequellae, with particular attention being paid to the potential finger joint injury. Surgical exploration is frequently indicated, debridement, irrigation and antimicrobial therapy being required. Viral transmission, as well as bacterial infection, can result from bites.

With regard to envenomation, often a great deal of time and effort is directed at identifying the offending animal and focusing on a specific toxin. It is important to ensure effective general resuscitation first. Thereafter, specific antivenom and antianaphylaxis measures may be taken.

A description of the three common envenomation symptom complexes -cyto-complex, neuro-complex and haemo-complex - is presented, along with some causative sources. Principles of resuscitation, wound care and general treatment measures are indicated, and then appropriate specific treatments are recommended.

Bites and envenomations vary in different parts of the world and it is important that emergency departments develop appropriate protocols relevant to their locations. Common poisonous animal sources should be identified and symptom complexes anticipated. Specific antivenom therapy, appropriate to the area, should be available. However, the general principles of resuscitation and wound care have pride of place.

Triage for Leiurus quinquestriatus scorpion envenomation in children--is routine ICU hospitalization necessary?

(1) Leiurus quinquestriatus scorpion (LQS) envenomation is a common public health problem with a similar clinical presentation in the Middle East and worldwide: localized reactions occur in up to 97% of the victims. (2) LQS envenomation in children is potentially fatal since the severity of symptoms is weight-dependent. (3) A common policy is to hospitalize all children stung by the LQS-regardless of clinical severity-in the pediatric intensive care unit (PICU). (4) Seventeen of 18 children treated at two Israeli medical centers during an 8-year period developed mild to moderate clinical manifestations (antivenin was given in the one severe case; all children survived): all 18 had been transferred to an ICU for surveillance. Since patient care in PICUs is far more costly and manpower-intense than in general emergency rooms, we propose that a protocol of 6 h of surveillance in the emergency department is adequate and safe for most children who had been stung by LQS. Only children who develop systemic manifestations should be hospitalized and transferred to the intensive care unit. (5) Further prospective studies should be conducted to define specific subgroups that may benefit from these recommendations.

Continuous intravenous midazolam infusion for Centruroides exilicauda scorpion envenomation

STUDY OBJECTIVE

We sought to describe the effects of continuous intravenous midazolam infusion as therapy for severe bark scorpion (Centruroides exilicauda) envenomation.

METHODS

A retrospective chart review from July 1, 1993, through January 1, 1998, identified all patients treated at a university hospital with International Classification of Diseases, Ninth Revision, codes 989.5 (toxic effect of venom) or E905.2 (scorpion sting causing poisoning). By using standardized collection forms, data were extracted from the medical record of every patient who had a grade III or IV envenomation and was treated with a continuous intravenous midazolam infusion.

RESULTS

Our search identified 104 patients; 34 had grade III or IV envenomation. Of these, 33 were treated in the ICU with continuous intravenous midazolam infusion. Median patient age was 4 years (range, 1 to 68 years). Midazolam dosage was adjusted to induce a light sleep state to control agitation and involuntary motor activity. The median amount of midazolam resulting in the first recorded decrease in agitation and involuntary motor activity was 0.30 mg/kg (range, 0.03 to 1.76 mg/kg). This first evidence of clinical improvement was recorded as 1.00 hour (median), with a range of 0.00 to 3.75 hours. The initial midazolam infusion rate was 0.10 mg x kg(-1) x h(-1) (median), with a range of 0.01 to 0.31 mg x kg(-1) x h(-1). The maximal midazolam infusion rate was 0.30 mg x kg(-1) x h(-1) (median), with a range of 0.06 to 1.29 mg x kg(-1) x h(-1). The median time until the maximal midazolam infusion rate was 2.5 hours (range, 0.00 to 8.50 hours). The median duration of infusion was 9. 50 hours (range, 4.25 to 20.50 hours). The median length of stay in the ICU was 15.17 hours (range, 6.0 to 28.0 hours), and 85% of patients were discharged directly home. All patients had resolution of abnormal motor activity and agitation during their midazolam infusion. Transient hypoxemia without evidence of end-organ dysfunction was documented in 4 patients during midazolam therapy.

CONCLUSION

A continuous intravenous midazolam infusion can be a safe, effective, and readily available treatment option for patients with grade III or IV C exilicauda envenomation.

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.