[Cardiovascular dysfunction following severe scorpion envenomation. Mechanisms and physiopathology]

Comparison of the Scorpionism Caused by Centruroidesmargaritatus, Tityuspachyurus and Tityus n. sp. aff. metuendus Scorpion Venoms in Colombia

Among other scorpion species, Colombia has two genera of the Buthidae family Centruroides and Tityus, considered to be dangerous to humans. This research shares scientific knowledge aiming to a better understanding about the pathophysiological effects of such venoms. The venom of the three species: Centruroides margaritarus, Tityus pachyurus, and T. n. sp. aff. metuendus with biomedical interest were studied. An initial pre-glycemic sample was taken from ICR mice. They were later intraperitoneally inoculated with doses of 35% and 70% of LD₅₀ of total venom. Poisoning signs were observed during a 6-h period to determine the level of scorpionism. After observation, a second glycemic sample was taken, and a histopathological evaluation of different organs was performed. This work revealed that all three venoms showed considerably notorious histopathological alterations in main organs such as heart and lungs; and inducing multiple organ failure, in relation to the glycemia values, only C. margaritatus and T. n. sp. aff. metuendus showed significant changes through manifestation of hyperglycemia. According to the Colombian scorpionism level; signs were mild to severe affecting the autonomous nervous system.

Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review of the Literature

Scorpion sting is a public health issue in several countries, particularly in America, the Middle East, India and Africa. The estimated annual global incidence of scorpion envenomings is about 1.5 million, resulting in 2600 deaths. Scorpions are Arthropoda characterized by a tail ending in a terminal bulbous (telson) containing paired venom glands and the stinger. There are 19 known families of scorpions and more than 2200 species, of which about 50 from the families of Buthidae, Hemiscorpiidae and Scorpionidae are harmful to humans. Scorpion venom is a complex structure composed of neurotoxic proteins, salts, acidic proteins and organic compounds, thereby having neurologic, cardiovascular, hematologic and renal side effects, in addition to local effects such as redness, pain, burning and swelling. When the sting is fatal, the mechanism of death is often related to cardiotoxicity with terminal pulmonary edema. However, the cholinergic excess or the neuromuscular excitation can provoke respiratory failure. Sometimes, death is due to an anaphylactic reaction to the envenoming. The purpose of this literature review is to evaluate the autopsy findings in scorpion sting-related deaths in order to better understand the pathophysiological mechanisms underlying them, thus helping pathologists in defining the correct diagnosis.

Involvement of the Endothelin Receptor Type A in the Cardiovascular Inflammatory Response Following Scorpion Envenomation

Elevated levels of endothelin-1 (ET-1) were recorded in sera of scorpion sting patients. However, no studies focused on the mechanism of ET-1 involvement in the pathogenesis of scorpion envenomation, particularly in the cardiovascular system which is seriously affected in severe cases of scorpion stings. Inflammation induced by Androctonus australis hector (Aah) scorpion venom in the heart together with the aorta was studied in mice pretreated with a specific endothelin A receptor (ETA-R) inhibitor. ETA-R inhibition resulted in the attenuation of the high amounts of cytokine (tumor necrosis factor alpha (TNF-α) and interleukin-17 (IL-17)) recorded in the sera of envenomed mice. The recovery of the oxidative stress marker balance and matrix metalloproteinase (MMP) expression were also observed, concomitantly with the reduction of tissular neutrophil infiltration. Additionally, the cardiac and the aortic tissue alterations, and the metabolic enzymes (creatine kinase (CK) and muscle–brain isoform creatine kinase (CK-MB)) overspread into sera were significantly attenuated. Obtained results suggest the implication of endothelin throughout its ETA receptors in the inflammatory response observed in the cardiovascular components during scorpion envenomation. Further knowledge is needed to better understand the implication of the endothelin axis and to improve the therapeutic management of severe scorpion sting cases.

Uncommon presentation of scorpion sting at teaching hospital

Scorpion envenomation is a major public health problem in tropical and sub-tropical countries, especially in Africa, Middle East, Latin America, and India. Even though most of the scorpion envenomation are harmless, it is generally seen with a set of clinical features, such as pain, edema, numbness, and tenderness in the area of the sting but rarely have serious clinical sequelae with involvement of vital organ systems like cardiovascular system and respiratory system leading to fatal manifestations like acute pulmonary edema, acute heart failure, and acute respiratory distress syndrome (ARDS). Here we present a case of a 19-year-old village boy who developed myocarditis and cardiogenic shock following scorpion envenomation, which was successfully treated with vasopressors, non invasive ventilation, and other supportive care.

Value of troponin levels in the diagnosis of cardiac dysfunction in moderate scorpion envenomation

Context:

Cardiac dysfunction is one of the most serious consequences of scorpion envenomation. The best tool to evaluate cardiac function is echocardiography, but it is not available at all emergency departments. Many studies aimed to describe biological predictive factors of cardiac dysfunction in scorpion envenomation. Troponin is one of these biomarkers but its correlation with myocarditis is not well established. The aim of this study was to evaluate correlation between troponin levels and cardiac dysfunction in moderate scorpion envenomation.

Methods:

A retrospective monocentric study including patients admitted in the emergency department for moderate scorpion envenomation with troponin measurement during their early management. On arrival, an electrocardiogram and a chest X-ray were realized for all patients.

Results:

We enrolled 132 patients with a mean age at 31.3 ± 24.4 years and a 1.35 sex-ratio. All patients had moderate systemic manifestations. There were 28 patients with clinical manifestations of cardiac dysfunction without life-threatening troubles (21.2%). Troponin was undetectable in 69 patients (56%). The mean value of troponin level (pg/ml) was higher in patients with clinical manifestations of left ventricular dysfunction (1.80 ± 3.8 vs. 0.11 ± 0.5; p = 0.02). Troponin levels were significantly higher in patients with positive T wave on electrocardiogram.

Conclusion:

In patients with moderate scorpion envenomation with positive T wave, high values of troponin suggest the presence of cardiac dysfunction.

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 bite, a sting to the heart!

Scorpion bites are common in India. Usually, these bites are harmless but sometimes have serious clinical sequelae, including death. We report herein a case of scorpion bite with electrocardiographic abnormalities simulating early myocardial infarction. Pulmonary edema and congestive heart failure accompanied these electrocardiographic changes as well as serum cardiac markers. The etiology of cardiovascular manifestations in severe scorpion sting is related to venom effect on sympathetic nervous system and the adrenal secretion of catecholamines as well as to the toxic effect of the venom on the myocardium itself. It is a rare case of scorpion sting presented as myocardial infarction and heart failure, successfully treated with Intensive Care Unit care, noninvasive ventilation, vasopressors, and antiischemic treatment.

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.

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.

Scorpion toxin of Androctonus australis garzonii induces neuropeptide Y release via bradykinin stimulation in rat atria and kidneys

The ability of scorpion toxins to produce hemodynamic alterations is well documented but all mediators implied in cardiovascular disturbances are not known. In the present investigation we studied the effect of North African Androctonus australis garzonii scorpion toxin on neuropeptide Y (NPY) release from rat atria and kidneys by a perifusion system in vitro. To further understand the mechanisms of the scorpion toxin action on NPY release, the effects of icatibant (HOE 140, a selective bradykinin-B2 receptor antagonist), tetrodotoxin (TTX, a sodium channel antagonist) and diltiazem (a calcium channel antagonist), and the effect of the scorpion toxin on bradykinin (BK, a potent vasorelaxant peptide of the kinin group) release were studied in both tissues. We showed that the scorpion toxin (10(-6)M) increased the NPY release from both atria (35%) and kidneys (40%). This increase was significantly (p<0.001) inhibited by HOE 140 (10(-5)M). The scorpion toxin (10(-6)M) enhanced BK secretion in both atria (52%) and kidneys (55%). Diltiazem (10(-5)M) and TTX (10(-5)M) decreased by 45-75% NPY levels induced by scorpion toxin in both organs. The results show that A. australis garzonii scorpion toxin stimulates NPY release from both rat atria and kidneys, and suggest that the toxin induces NPY release via BK stimulation through B2 receptors. This effect appears to involve calcium and sodium channel activation.

[Peripartum cardiomyopathy: incidence, pathogenesis, diagnosis, treatment and prognosis]

INTRODUCTION

Peripartum cardiomyopathy (PPCM) is a rare and life-threatening disease of unknown aetiology. The primary objective of this review was to analysed aetiopathogeneses, clinical presentation and diagnosis, as well as pharmacological, perioperative and intensive care management and prognosis of this pathology.

METHODS

We undertook a systematic review of the literature using Medline, Google Scholar and PubMed searches.

RESULTS

Unlike other parts of the world in which cardiomyopathy are rare, dilated cardiomyopathy is a major cause of heart failure throughout Africa. Its aetiopathogenesis is still poorly understood, but recent evidence supports inflammation, viral infection and autoimmunity as the leading causative hypotheses. This diagnosis should be limited to previously healthy women who present with congestive heart failure (CHF) and decreased left ventricular systolic function in the last month of pregnancy or within 5 months after delivery. Recently, introduction of echocardiography has made diagnosis of PPCM easier and more accurate. Conventional treatment consists of diuretics, vasodilators, and sometimes digoxin and anticoagulants, usually in combination. Patients who fail to recover may require inotropic therapy. In resistant cases, newer therapeutic modalities such as immunomodulation, immunoglobulin and immunosuppression may be considered. Prognosis is highly related to reversal of ventricular dysfunction. Compared to historically higher mortality rates, recent reports describe better outcome, probably because of advances in medical care. Based on current information, future pregnancy is usually not recommended in patients who fail to recover normal heart function.

CONCLUSION

PPCM is a rare but serious form of cardiac failure affecting women in the last months of pregnancy or early puerperium. Its aetiopathogenesis is still poorly understood. Introduction of echocardiography has made diagnosis of PPCM easier and more accurate. Prognosis is highly related to reversal of ventricular dysfunction.

A new venomous scorpion responsible for severe envenomation in Argentina: Tityus confluens

In Argentina the scorpions of medical importance belong to the genus Tityus (T.), particularly the species T. trivittatus, the only scorpion whose sting is recognized to be associated with severe human envenoming and death. This genus is distributed from the north of the Patagonian region to the center and some provinces in the north of the country. During the period 2003-2006 four children died following scorpion stings, of which one was certainly and three were probably by T. confluens. In 2006, in the province of Tucumán, a girl died by scorpion envenoming and the scorpion responsible for the death, found in her shoe, was T. confluens. We thus studied the toxicity of venom gland homogenates from T. confluens from the provinces of Jujuy and Catamarca, and of crude venom from specimens from Catamarca and the province of La Rioja. The lethal potencies of the telson homogenates were 7.0 and 18.6microg/g for Jujuy and Catamarca, respectively, while the lethal potency of the crude venom was 0.7microg/g. Injected mice showed generalized congestion and hepatic lesions. Pancreatic damage was observed in some animals. Lungs showed congestion and foci of hemorrhage and mild edema. The heart showed injury in the muscular fibers. The venom showed high reactivity against anti-T. trivittatus antivenom and against two anti-T. serrulatus antivenoms. The anti-T. trivittatus antivenom neutralized the lethal activity of T. confluens venom. In addition, the venom reacted very slightly against an anti-Centruroides antivenom. Therefore, the stings of this scorpion must be considered of risk for humans to the same degree as the stings of T. trivittatus.

Epidemiological, clinical characteristics and outcome of severe scorpion envenomation in South Tunisia: multivariate analysis of 951 cases

The aim of this retrospective descriptive study was to describe both epidemiologically and clinically manifestations following severe scorpion envenomation and to define simple predictive factors which can be used in routine practice in general Intensive Care Units (ICU) as an indicator of poor prognosis. Cases were collected from hospital patients' files during 13-year (1990-2002) period in the medical Intensive Care Unit of a university hospital (Sfax - Tunisia). The diagnosis of scorpion envenomation was based on a history of scorpion sting. Nine hundred fifty-one patients, who were admitted for a scorpion sting, were analyzed. There were 769 patients (80.8%) in the grade III group (with cardiogenic shock and/or pulmonary edema or severe neurological manifestation (coma and/or convulsion)) and 182 patients (19.2%) in the grade II group (with systemic manifestations). Scorpion envenomation is more frequent in summer; indeed 82.3% of our patients were admitted between June and September. The mean age (+/-SD) was 14.7 +/- 17.4 years, ranging from 0.5 to 90 years. In this study 739 patients (77.8%) had neuromuscular signs, 700 patients (73.6%) had gastrointestinal signs and 585 patients (61.5%) had a pulmonary edema, while 195 patients (20.5%) had a cardiogenic shock. The mean blood sugar on admission was at 11.32 +/- 5.66 mmol/l, a high blood sugar level (>11 mmol/l) was observed in 39% of cases. The mean blood urea was at 7.1 +/- 3.2 mmol/l, it was above 10 mmol/l in 10.7% of cases. The mean of leucocytes was at 17 418 +/- 7833 cells/mm(3), it was above 11 000/mm(3) in 80% of cases. In the end of the stay in ICU, evolution was marked by the improvement of 879 patients (92.5%) while 72 patients (7.5%) died. A multivariate analysis found the following factors to be correlated with a poor outcome: age less than 5 years (OR = 2.27), fever >38.5 degrees C (OR = 2.79), coma with Glasgow coma score < or =8/15 (OR = 9.87), pulmonary edema (OR = 8.46), leucocytes >25 000 cells/mm3 (OR = 2.35) and blood urea >8 mmol/l (OR = 4.02). Moreover, in children group, a significant association was found between PRISM score and mortality rate, this model had a high discriminative power with an area under the ROC curve at 0.93. In the adult patients a significant association was found between SAPS II score and mortality rate, this model had a high discriminative power with an area under the ROC curve at 0.82. In summary, in severe scorpion envenomation, age less than 5 years, fever >38.5 degrees C, coma with Glasgow coma score < or =8/15, pulmonary edema, leucocytes >25 000 cells/mm3 and blood urea >8 mmol/l were associated with a poor outcome.

[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.

Unusual presentations of scorpion envenomation

Scorpions are nocturnal arthropods that inject their venom through the victims’ skin by stingers. By the envenomation, clinical manifestations in a wide spectrum may occur, including pain at one side and death because of severe cardiopulmonary or neurological abnormalities. Sometimes the victim cannot describe the insect or does not remember even being stung after the event. We present two cases of scorpion envenomation with different and rare clinical situations with a short review of the literature.

Acute myocardial infarction in a young man caused by centipede sting

It is known that insects can cause various clinical effects such as myocardial ischaemia and hypotension from vasospasm and the myocardial toxic effects of the venom and anaphylaxis. Although myocardial ischaemia resulting from centipede sting has been reported once before, myocardial injury has not. In this report, the authors present the case of a 20 year old male patient bitten by a centipede and admitted to the emergency room with chest pain, abnormal electrocardiographic findings, and increased cardiac enzymes (cardiac troponin T) suggesting acute myocardial infarction.

Serum levels of IL-6 and its soluble receptor, TNF-α and chemokine RANTES in scorpion envenomed children: Their relation to scorpion envenomation outcome

During the present study, 30 children in Upper Egypt (less than 12 years old) were admitted to Pediatric Intensive Care Unit because of scorpion envenomation. They were compared with 20 apparently normal children of matching age and sex as controls. The victims and controls were subjected to complete clinical examination and full blood picture. The serum levels of interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), regulated upon activation normal T cells expressed and secreted (RANTES ) and tumour necrosis factor-alpha (TNF-alpha) were determined once for the controls and twice for the victims, the first sample on admission and the second sample after 24h. All victims showed significantly higher mean values of IL-6, sIL-6R, RANTES, TNF-alpha, and leucocytic count both on admission and on the follow up when compared with controls. According to the clinical manifestations of envenomation, 40% of the victims had a mild envenomation manifestation, while 60% of them had severe manifestations. The severely envenomed children showed significantly higher mean values of IL-6, sIL-6R, TNF-alpha, RANTES and leucocytic count both on admission and on the follow up samples when compared with the mild cases. The non-survival victims (five victims) showed significantly higher mean values of IL-6, sIL-6R, TNF-alpha, RANTES and leucocytic count both on admission and on the follow up samples in comparison to the survivals. Furthermore, those fatal cases showed a non-significant decline in the serum levels of IL-6, sIL-6R, TNF-alpha, RANTES and leucocytic count on the following up samples, while the survivals showed a significant decline in the serum levels of these parameters on the following up samples. In conclusion, these data revealed that IL-6, sIL-6R, TNF-alpha and chemokine, RANTES are involved in the pathogenesis of scorpion envenomation and correlated with its severity.