A clinical score predicting the need for hospitalization in scorpion envenomation

Use of point-of-care ultrasound to assess the severity of scorpion stings in hospitalized patients

INTRODUCTION

Scorpionism is a public health problem, especially in tropical regions. In Brazil, the prevalence of envenomation by scorpions is high, and the average national lethality is around 0.16 percent. The Tityus serrulatus scorpion is the primary species of medical importance. However, objective tools to predict and define the severity of these envenomations are lacking.

MATERIALS AND METHODS

This was an observational study conducted among patients aged 0-19 years with scorpionism. Patients were admitted to a reference hospital between December 2020 and May 2022. Point-of-care ultrasound was performed within 24 hours of the scorpion sting.

RESULTS

Forty-nine patients were included, with a median age of 3.6 (interquartile range 2.3-5.3) years and a predominance of females (51 percent). Fifteen patients (30.6 percent) presented major life-threatening signs, 32 (65.3 percent) minor systemic manifestations, and two (4.1 percent) only local manifestations. Left ventricular dysfunction was identified in 13 patients (26.5 percent). Ten patients (20.4 percent) presented pattern B (visualization of three or more B lines in the evaluated quadrant) in at least one lung window. The sensitivity and specificity of cardiac and pulmonary ultrasound to identify the most severely ill patients were 86 percent and 94 percent, respectively.

DISCUSSION

The changes found on point-of-care ultrasound were associated with life-threatening signs. All patients with class III envenomation were referred to the intensive care unit, showing the importance of early identification of this subgroup. The main limitations were the small sample size and the fact that admission to intensive care was not based on systematic criteria.

CONCLUSIONS

Point-of-care ultrasound is able to identify early signs of pulmonary congestion and heart failure in scorpionism. It can be useful for the objective selection of patients who are at a higher risk of complications and death and who require intensive support; it may also be valuable for periodic reassessments. Point-of-care ultrasound is a valuable tool for identifying and monitoring severe cases of scorpionism.

Echocardiographic Evaluation of the Response to Prazosin Treatment in Scorpion Sting

BACKGROUND

Scorpion envenomation is a major public health problem in children that can induce lethal neurological, respiratory and cardiovascular complications. We aimed to evaluate cardiovascular complications with a follow-up of envenomed children for 1 month for possibility of incomplete recovery.

METHODS

This was a prospective study conducted for children who presented with scorpion sting to Emergency and Intensive Care units. Demographic, clinical and laboratory findings of patients were recorded. Cases with suspected clinical and electrocardiographic manifestations of myocarditis were subjected to bedside echocardiography with follow-up at the end of the first week and the first month.

RESULTS

Scorpion sting cases presented to our hospital were 81 cases during 1-year study; of them, 17 cases were stable without systemic manifestations after 12 h observation and discharged. Sixty-four cases suffered systemic organic complications and needed ICU admission; their mean age was 11.52 ± 3.74 and 64% of them were males. Twenty-eight of admitted cases showed manifestations of myocarditis and by echocardiography, all of them had evidence of left ventricular dysfunction. On follow-up, there was significant improvement at the end of first week and complete improvement at the end of first month except three cases who died due to pulmonary edema and cardiogenic shock.

CONCLUSION

Acute toxic myocarditis is a common and an important cause of morbidity and mortality following scorpion envenomation that necessitates early and aggressive management. High index of suspicion, serial electrocardiogram monitoring and echocardiography are three integrative lines required to recognize this serious complication. Lay summaryAcute toxic myocarditis is a common cause of morbidity and mortality following scorpion envenomation that necessitates rapid medical treatment. We aimed to evaluate cardiovascular complications after scorpion sting with a follow-up of envenomed children for 1 month for possibility of incomplete recovery. Tachycardia was the most frequent observed cardiac sign followed by hypotension, while the least was bradycardia and hypertension. All cases with manifestations suggestive of myocarditis were evaluated by bedside two-dimensional echocardiography and showed evidence of left ventricular dysfunction, that begin to regress within 1 week of treatment unless progressive pulmonary edema and resistant cardiogenic shock occurred. On follow-up for survivors, complete improvement at the end of first month was noticed. Clinical suspicion, serial ECG monitoring and echocardiography are required for rapid and early diagnosis. Early use of prazosin therapy can prevent long-term residual damage as evidenced by echocardiographic evaluation.

Scorpion envenomation: state of the art

Scorpion envenomation is common in the tropical and subtropical regions. It poses a major public health problem with some patients having serious clinical manifestations and severe complications including death. Old World and New World scorpions are usually contrasted because of differences in venom composition, clinical presentation and severity, and, accordingly, different therapeutic approaches. The majority of scorpion stings are either dry or result in low amounts of injected venom, thus explaining why up to 95% of scorpion stings ensue only in local signs. For a clinical envenomation to occur, it has been suggested that the interaction between the quantity of venom introduced in the body of the prey and the distribution volume should ensue in a critical threshold of scorpion toxin plasma concentration. In this case, there is a massive release of neurohormonal mediators (mainly catecholamine), with systemic vasoconstrictor effects eliciting a sharp increase in systemic arterial pressure and LV-filling pressure and decreased cardiac output. This early phase of cardiac dysfunction, also called "vascular phase", is followed by a severe cardiomyopathy, a form of Takotsubo cardiomyopathy, involving both ventricles and reversible in days to weeks. The more comprehensive understanding of the disease pathophysiology has allowed for a well-codified symptomatic treatment, thus contributing to a substantial reduction in the death toll of scorpion envenomation over the past few decades. The standard intensive-care treatment (when available) overcomes envenomation's consequences such as acute pulmonary edema and cardiogenic shock. Even though it continues to inspire many evaluative studies, immunotherapy seems less attractive because of the major role held by mediators in the pathogenesis of envenomation, and unfavorable pharmacokinetic properties to existing sera compared to venom. Meta-analyses of controlled trials of immunotherapy in severe scorpion envenomation reached similar conclusions: there is an acceptable level of evidence in favor of the use of scorpion antivenom (Fab'₂) against Centruroides sp. in USA/Mexico, while there is still a need for a higher level of evidence for immunotherapy in the Old World envenomation.

Evaluation of Scorpion Envenomation by Tityus trivittatus in Adults: An Analysis of Variables Related to Severity of Clinical Presentation

INTRODUCTION

In Argentina, the scorpion species Tityus trivittatus has been the species most commonly associated with serious injury and death.

METHODS

We performed a retrospective study of cases of T trivittatus envenomation that presented to the emergency department at an infectious disease hospital in Cordoba, Argentina, between December 2014 and February 2015. All cases were taxonomically confirmed using criteria established in the Argentine Ministry of Health national guidelines. The primary outcome was classification of clinical presentation (mild/moderate/severe). Classification of clinical presentation was performed in a post hoc fashion using the national guidelines and compared to the classification of clinical presentation given to patients at the time of diagnosis in the emergency department.

RESULTS

We included 450 individuals with T trivittatus envenomation. The median age of was 36 y (interquartile range 25-52), and 57% were female. In the emergency department, only 5 patients (<1%) were diagnosed as moderate cases and received antivenom; all other cases were diagnosed as mild. Conversely, in our post hoc classification of clinical presentations, 280 patients had mild presentations, 170 had moderate presentations, and no patients had severe presentations. In our cohort, there were no deaths, no inpatient hospital admissions, and no requirements for continuous cardiac monitoring. We found that age >50 y, (odds ratio [OR] 2.5, P<0.001), time from sting to presentation >120 min (OR 2.6, P=0.02), and pre-existing hypertension (OR=3.9, P<0.001) were all independently associated with worse post hoc classification severity.

CONCLUSIONS

Our study exposed factors associated with moderate presentations of scorpion envenomation and proposes the option of conservative treatment for affected adults.

Endocrinological and biochemical changes of scorpionism in children in Upper Egypt

AIM

The aim of this study was to determine some endocrinological and biochemical changes of scorpionism in children in Upper Egypt. In addition, it aimed to find any possible relationship between these changes and the severity of scorpionism.

PATIENTS AND METHODS

The present study was carried out at two university hospitals in Upper Egypt and included 42 children with envenomation and 20 apparently healthy children as controls. In all subjects, levels were measured of noradrenaline, aldosterone, insulin and cortisol, and some biochemical parameters and electrolytes including nitric oxide (NO), creatine phosphokinase (CPK), Na+ and K+.

RESULTS

Na+, NO and CPK levels were significantly higher in children with envenomation compared with the controls. Also, there was a significant reduction in K+ in patients compared with controls. Children with severe envenomation had significantly higher levels of noradrenaline, cortisol and aldosterone compared with the controls and mild cases. However, insulin levels were significantly decreased in severe cases of scorpionism compared with mild ones. Moreover, hyperglycemia was detected in all patients with envenomation compared with controls, with significantly higher blood glucose levels among children with severe envenomation compared with mild cases.

CONCLUSION

Endocrinological changes were common in all children with scorpion envenomation and more obvious in cases of severe envenomation. The released mediators may account for several inflammatory manifestations such as pulmonary edema, myocardial failure, systemic inflammatory response syndrome and multiple organ failure. The use of insulin is recommended in cases of severe envenomation to improve the outcome.

Study of severe scorpion envenoming following subcutaneous venom injection into dogs: Hemodynamic and concentration/effect analysis

To evaluate the dose-effects of Androctonus australis hector (Aah) venom injected subcutaneously on hemodynamics and neurohormonal secretions, 10 anesthetized and ventilated mongrel dogs, were split in two groups (n = 5/group). Subcutaneous injection was done with either 0.2 mg/kg or 0.125 mg/kg of the purified G50 scorpion toxic fraction. Hemodynamic parameters using right heart catheter were recorded and plasma concentrations of catecholamine, troponin, and serum toxic fraction were measured sequentially from baseline to 120 min. We identified the dose of toxic fraction evoking characteristic hemodynamic perturbation of severe envenomation, the time-lapse to envenomation, and the associated plasma level. The injection of 0.125 mg/kg toxic fraction was not associated with significant variations in hemodynamic parameters, whereas the 0.2 mg/kg dose caused envenomation characterized by significant increase in plasma catecholamines, increased pulmonary artery occluded pressure, mean arterial pressure, and systemic vascular resistance (p < 0.05), in association with sustained decline in cardiac output (p < 0.001). Envenomation occurred by the 30th minute, and the corresponding concentration of toxic fraction was 1.14 ng/ml. The current experiment allowed the identification of the sub-lethal dose (0.2 mg/kg) of the toxic fraction of Aah administered by the subcutaneous route. Two parameters with potential clinical relevance were also uncovered: the time-lapse to envenomation and the corresponding concentration of toxic fraction.

Scorpion sting nephropathy

Scorpion envenomations are ubiquitous, but nephropathy is a rare manifestation, reported mainly from the Middle East and North Africa. Rapid venom redistribution from blood, delayed excretion from the kidneys, direct toxicity of venom enzymes, cytokine release and afferent arteriolar constriction have been seen in experimental animals. Haemoglobinuria, acute tubular necrosis, interstitial nephritis and haemolytic–uraemic syndrome have been documented in human victims of scorpion envenomation. Epidemiology, venom components and toxins, effects on the laboratory mammals especially the kidneys and reports of renal failure in humans are reviewed in this article.

Scorpion envenomation among children: clinical manifestations and outcome (analysis of 685 cases)

Our objective was to characterize both epidemiologically and clinically manifestations after severe scorpion envenomation and to define simple factors indicative of poor prognosis in children. We performed a retrospective study over 13 years (1990-2002) in the medical intensive care unit (ICU) of a university hospital (Sfax-Tunisia). The diagnosis of scorpion envenomation was based on a history of scorpion sting. The medical records of 685 children aged less than 16 years who were admitted for a scorpion sting were analyzed. There were 558 patients (81.5%) in the grade III group (with cardiogenic shock and/or pulmonary edema or severe neurological manifestation [coma and/or convulsion]) and 127 patients (18.5%) in the grade II group (with systemic manifestations). In this study, 434 patients (63.4%) had a pulmonary edema, and 80 patients had a cardiogenic shock; neurological manifestations were observed in 580 patients (84.7%), 555 patients (81%) developed systemic inflammatory response syndrome (SIRS), and 552 patients (80.6%) developed multi-organ failure. By the end of the stay in the ICU, evolution was marked by the death in 61 patients (8.9%). A multivariate analysis found the following factors to be correlated with a poor outcome: coma with Glasgow coma score ≤ 8/15 (odds ratio [OR] = 1.3), pulmonary edema (OR = 2.3), and cardiogenic shock (OR = 1.7). In addition, a significant association was found between the development of SIRS and heart failure. Moreover, a temperature > 39°C was associated with the presence of pulmonary edema, with a sensitivity at 20.6%, a specificity at 94.4%, and a positive predictive value at 91.7%. Finally, blood sugar levels above 15 mmol/L were significantly associated with a heart failure. In children admitted for severe scorpion envenomation, coma with Glasgow coma score ≤ 8/15, pulmonary edema, and cardiogenic shock were associated with a poor outcome. The presence of SIRS, a temperature > 39°C, and blood sugar levels above 15 mmol/L were associated with heart failure.

Clinical pathology alterations in pregnant and non-pregnant rats following scorpion envenomation

Scorpion envenomation is a growing problem in many countries, especially among women and children. Existing diagnostic criteria are not sufficiently specific to allow antivenin administration in the absence of a confirmed scorpion sting. This study was performed to evaluate conventional haematological and serum chemical measurements as potential indices of scorpion envenomation. Adult, cycling nulliparous and near-term primiparous, white Wistar rats received a single subcutaneous injection of crude venom (600 µg/kg) from the Buthidae scorpion (Buthus occitanus tunetanus). All envenomed rats were observed for external signs and symptoms of toxicity until necropsy, which entailed terminal blood collection at either 0.5, 1, 2, or 4 hr after venom administration (n = 6 per reproductive state per time-point) for evaluation of selected clinical chemistry and haematological analytes. Control cohorts (matched for age and reproductive state) received saline injections subcutaneously and were necropsied at 0.5 hr. Almost all envenomed rats but no control animals displayed physical symptoms of intoxication, including agitation, mastication with hypersalivation, and/or vocalizing. Reproducible alterations in clinical pathology parameters were lacking in venom-treated rats regardless of reproductive status, although modest but significant Rho correlations suggested that mild haemoconcentration, haemolysis, renal function deficits and possibly coagulation difficulties developed over time.

Epidemiology of scorpionism: a global appraisal

The scorpionism is an actual public health problem in several parts of the world because, either incidence, or severity of envenomations is high and managed with difficulty by health services, or for these two reasons at the same time. The treatment of scorpion envenomation is complex and controversial, in particular regarding the utility of the antivenoms and symptomatic treatments that must be associated. The authors reviewed the literature of last 30 years to discuss the epidemiologic importance of scorpionism and to point out the principal therapeutic or preventive measures. According to the most recent studies, seven areas were identified as at risk: north-Saharan Africa, Sahelian Africa, South Africa, Near and Middle-East, South India, Mexico and South Latin America, east of the Andes. These involve 2.3 billion at risk population. The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%). Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher. Improvement of therapeutic management would reduce the lethality very significantly.

[Management of scorpion sting in Morocco]

Scorpion stings are the first cause of poisoning, and represent between 30 and 50% of all cases reported to the Moroccan Poison Control Centre. Concerned by the size of the problem, we have paid special attention to this pathology. Through retrospective and prospective studies, it has been possible to determine the nature and the chronology of clinical stages, as well as the epidemiological, clinical and therapeutic factors of gravity. On this basis, we worked out a new management to provide support for patients. This management will standardize support provided at the national level, and will reduce the number of lethal case and rationalize spending by reviewing medication, transfer of patients and hospital care. This standardization is an essential component of the national strategy against scorpion poisoning. Other components include training of medical staff, awareness campaigns, and information systems to monitor lethal cases. A survey over five years shows a reduction in the number of lethal cases and rationalization of costs. Medical care provided rests upon the distinction between patients stung by scorpions and patients actually poisoned. The first category of patients will be monitored up to four hours after the scorpion sting, while poisoned patients will be transferred to an intensive care unit.