Inverted Takotsubo syndrome in Androctonus australis scorpion envenomation.

CONTEXT: The nature of scorpion-related cardiomyopathy is still a matter of debate where specific toxin-induced cardiomyopathy, ischemic, or catecholaminergic cardiomyopathy is advocated as well. We report two cases of Takotsubo syndrome following envenomation by Androctonus australis, bringing new evidence for the fundamental role of catecholamines in the pathogenesis of this cardiomyopathy. Case 1: A woman aged 36 presented with pulmonary edema and shock following scorpion envenomation. Echocardiography-Doppler showed a LVEF at 30%. Cardiac magnetic resonance (CMR) imaging showed a basal ballooning of the left and right ventricles suggestive of an inverted biventricular Takotsubo syndrome. A second CMR performed after recovery was normal. Case 2: A woman aged 45 was admitted for pulmonary edema and shock consecutive to scorpion envenomation. Echocardiography showed a LVEF at 35%. CMR showed a basal ballooning. The patient was discharged four days following admission with a normal LV function on repeat echocardiography examination. CONCLUSIONS: Cardiomyopathy in these cases, following scorpion envenomation by Androctonus australis, fulfills the criteria of Takotsubo syndrome. These observations contribute to our understanding of the mechanism, prognosis, and treatment of scorpion-related cardiomyopathy.

Evaluation of myocardial function using tissue Doppler imaging in children with moderate scorpion envenomation.

CONTEXT: Scorpion envenomation is an important public health problem. It can cause life-threatening complications such as respiratory, neurological and cardiovascular compromise. Systemic envenoming signs and mortality rates are dramatically higher in children. OBJECTIVE: The objective of this study was to evaluate myocardial function using pulsed tissue Doppler imaging in patients with moderate scorpion envenomation. MATERIALS AND METHODS: The study was conducted from July to October 2009 in the South-East Anatolia region of Turkey. The study population consisted of 30 children with moderate scorpion envenomation and 30 age- and sex-matched normal controls. Severe and mild envenomations were excluded. In addition to echocardiographic examination, pulsed tissue Doppler imaging was performed. RESULTS: The average age was 7.6 ± 4.3 years in patients and 7.9 ± 3.2 years in controls (p value, 0.77). The mean heart rate was 114 ± 19 beats/min (range, 72-164) in patients and 95 ± 14 beats/min (range, 72-127) in controls (p < 0.01). Sinus tachycardia (> 120 beats/min in children) was detected in ten (33.3%) patients. Myocardial performance index (MPI) was obtained with tissue Doppler imaging. The ejection fraction, the fractional shortening, the MPI of the left ventricle, the MPI of the right ventricle, the left ventricular isovolumetric contraction time (ICT), the left ventricular isovolumetric relaxation time (IRT), the left ventricular ejection time, the right ventricular ICT, the right ventricular IRT and the right ventricular ejection were not statistically different between the patients and the controls (p > 0.05). DISCUSSION: We did not detect any considerable myocardial involvement in the children presenting with moderate scorpion envenomation except for sinus tachycardia. If the patients are treated with antivenom within 4 h, patients with moderate scorpion envenomation may not develop cardiac dysfunction.

Pre-clinical studies of toxin-specific nanobodies: evidence of in vivo efficacy to prevent fatal disturbances provoked by scorpion envenoming.

Scorpions represent a significant threat to humans and animals in various countries throughout the world. Recently, we introduced Nanobodies (Nbs) to combat more efficiently scorpion envenoming and demonstrated the performance of NbAahIF12 and NbAahII10 to neutralize scorpion toxins of Androctonus australis hector venom. A bispecific Nb construct (NbF12-10) comprising these two Nbs is far more protective than the classic Fab'(2) based therapy and is the most efficient antivenom therapy against scorpion sting in preclinical studies. Now we investigate the biodistribution and pharmacokinetics of (99m)Tc labeled Nbs by in vivo imaging in rodents and compared these data with those of the Fab'(2) product (PAS). The pharmacodynamics of the Nbs was investigated in rats by in vivo echocardiography and it is shown that NbF12-10 prevents effectively the hemodynamic disturbances induced by a lethal dose of venom. Moreover, even a late injection of NbF12-10 restores the heart rate and brings the blood pressure to baseline values. Histology confirms that NbF12-10 prevents lung and heart lesions of treated mice after envenoming. In conjunction, in this preclinical study, we provide proof of concept that NbF12-10 prevents effectively the fatal disturbances induced by Androctonus venom, and that the Nanobody based therapeutic has a potential to substitute the classic Fab'(2) based product as immunotherapeutic in scorpion envenoming. Further clinical study using larger cohorts of animals should be considered to confirm the full protecting potential of our NbF12-10.

Electrocardiologic and echocardiographic features of patients exposed to scorpion bite.

The purpose of this study is to examine clinical progress and hemodynamic and electrocardiologic features (QT depression and heart rate variability [HRV]) of patients exposed to a scorpion bite. Seventeen patients bitten by scorpions, and, as a control group, 15 healthy subjects were included in the study. Standard electrocardiograph (ECG) records, 24-hour Holter-ECG, and Doppler echocardiographic examinations were performed. Holter ECG indicated sinus tachycardia, sinus bradycardia, paroxysmal supraventricular tachycardia, atrial fibrillation, first-degree and second-degree atrioventricular block not requiring treatment, early atrial beats, and early ventricular beats in the patients at frequencies of 82%, 12%, 35%, 12%, 8%, 70%, and 47%, respectively. HRV parameters that reflected parasympathetic activity (SD 35+/-13-43+/-16, RMS-SD: 20+/-9-30+/-12, high frequency: 7.8+/-2-4.3+/-3, p<0.05) were significantly lower (p<0.05). Low frequency, which especially showed sympathetic activity (LF: 11+/-13-11+/-23, p>0.05), was similar in both groups. In addition, the LF/HF ratio, which reflected sympathovagal balance, was significantly increased in the patient group (1.5+/-1-3.0+/-2, p=0.005). Corrected QT and QT dispersion values were not significantly different with respect to the control (p>0.05). In the patient group compared to the control, a significant decrease was determined in the proportion of mitral E velocity to mitral A velocity (mEv/mAv), diastolic filling period (DFP), and left ventricular ejection fraction (LVEF), while a significant increase was noticed in pulmonary artery pressure (PAP) (mEv/mAv: 0.9+/-0.4-1.7+/-0.6, DFP: 362+/-8.5-425+/-89, LVEF: 53.1+/-6.7-68.6+/-5.8, PAP: 38.1+/-13-27.2+/-6, p<0.05). Scorpion bite leads to serious cardiovascular disorders, associated with decreased HRV, decreased systolic and diastolic functions, increased arrhythmic events, and hemodynamic disturbance with sympathetic and parasympathetic balance disturbance.

Assessment of left ventricular function in severe scorpion envenomation: combined hemodynamic and echo-Doppler study.

OBJECTIVE: To assess left ventricular function in patients presenting with pulmonary edema following scorpion envenomation. DESIGN: Cohort study. SETTING: Medical intensive care unit of a teaching hospital. PATIENTS: Nine consecutive adult patients stung by Androctonus australis and presenting with pulmonary edema entered the study. Fourteen normal volunteers comprised the control group. INTERVENTIONS: Upon admission, all patients had right heart catheterization and, within the first 8 h, a Doppler echocardiographic study. Results of Doppler echocardiographic studies were compared to those of controls. MEASUREMENTS AND RESULTS: Usual hemodynamic information (heart and vascular pressures, derived data and tissue oxygenation parameters), left ventricular dimensions and indicators of systolic function, and Doppler-derived parameters of left ventricular filling and diastolic function were obtained upon admission. Serial echocardiographic measurements were repeated daily until full clinical recovery (eight patients) or death (one patient). All patients had a hemodynamic profile of acute congestive heart failure (mean PAOP = 24 +/- 2 mmHg; mean SVI = 22 +/- 7 ml/m2; mean CI = 2.5 +/- 0.5 l/min/m2). However, SVR were not increased (mean = 22 +/- 3 U/m2). Left ventricle was hypokinetic in all patients with transient mitral regurgitation present in five patients. Left ventricular systolic function was markedly depressed (FS = 12 +/- 6%; EF = 26 +/- 12%). An associated diastolic dysfunction is suggested by Doppler records of mitral inflow. Left ventricular systolic function evolved toward normalization within 6 +/- 2 days preceded by full clinical recovery. CONCLUSIONS: These data suggest that pulmonary edema in scorpion envenomation is of hemodynamic origin and is related to a severe and prominent impairment of left ventricular systolic function.

Abnormal coronary perfusion in experimental scorpion envenomation.

Perfusion defects and left ventricular dilation after experimental scorpion envenomation were evaluated in five dogs. Left Left ventricular dilation was observed in three dogs and right ventricular dilation in one other, in scans immediately after envenomation. Perfusion defects were inferred from scans in four dogs. The data are strongly suggestive of coronary hypoperfusion, and the mechanics of abnormal coronary flow after scorpion envenomation are discussed.