Clinical update on scorpion envenoming

Abstract: Scorpion stings are currently the leading cause of venom-related injury to humans in Brazil and are a significant public health problem globally. Only scorpions of the Tityus genus are of medical importance in Brazil, and Tityus serrulatus is responsible for the most serious envenomations and deaths. The toxic effects of scorpion envenomation are due to a massive release of sympathetic and parasympathetic neurotransmitters; the severity is related to cardiac and hemodynamic changes, with cardiogenic shock and pulmonary edema contributing to the main causes of death. The pathophysiology of cardiac involvement has been discussed for decades and has been attributed to adrenergic discharge and a possible toxic effect of venom on the myocardium, while acute pulmonary edema may have a cardiogenic and/or non-cardiogenic origin. Currently, the clinical data point to catecholamine excess as the cause for reversible scorpion cardiomyopathy . These data include electrocardiographic changes, profiling of cardiac enzymes and troponin I, echocardiographic data with global or regional left ventricle dysfunction, and myocardial perfusion alterations compatible with spasm in the coronary microcirculation. Furthermore, recent data on cardiac magnetic resonance imaging findings, which are similar to those observed for stress-induced cardiomyopathy, have also been linked to catecholamine excess. The efficiency of antivenom serum treatment is controversial in the literature. Our experience in Brazil is that the management of patients with systemic manifestations of scorpion stings is based on three approaches, all of which are extremely important. These include symptomatic treatment, antivenom serum, and cardiorespiratory support.

Neuroimagem na dependência de jogos eletrônicos: uma revisão sistemática

Objetivo: Realizar revisão sistemática de manuscritos que utilizaram a neuroimagem no estudo da dependência de jogos eletrônicos, a fim de identificar as principais regiões cerebrais alteradas. Métodos: Foram realizadas buscas nos seguintes bancos de dados: ScieELO, BVS, Lilacs, Science Direct On Line e PubMed. Não houve data mínima para a pesquisa, sendo considerados os artigos encontrados até julho de 2013. Os descritores utilizados para a presente revisão sistemática da literatura foram: “PET”, “SPECT”, “MRI”, “DTI”, “EEG”, “imaging”, “neuroimaging”, “spectroscopy”, “functional magnetic ressonance”, “structural magnetic ressonance”, “tractography”, “voxel” e “brain”, individualmente cruzados com os descritores “gaming” e “video game addiction”. Resultados: Dos 52 artigos encontrados, 16 foram selecionados: nove usaram fMRI, quatro usaram sRMI, um usou PET e dois usaram EEG. Em relação às alterações funcionais e estruturais, elas foram mais observadas no lobo frontal (córtex pré-frontal dorsolateral, córtex orbitofrontal, giro pré-frontal, giro frontal médio), parietal, temporal (giro para-hipocampal), núcleos da base, tálamo, ínsula e cerebelo. Conclusão: A despeito dos métodos utilizados, os estudos apontaram convergências quanto às reciprocidades cerebrais. Essas alterações neurais são semelhantes às observadas em pacientes dependentes de substâncias e de internet, especialmente durante o estado de fissura. Apesar de apenas recentemente pesquisas de neuroimagem em dependentes de jogos eletrônicos terem sido realizadas, contamos no momento com achados significativos alinhados à compreensão dos mecanismos neurais associados à dependência de jogos eletrônicos e respectiva inserção como categoria nosológica no âmbito psiquiátrico.

Cardiopulmonary resuscitation: update, controversies and new advances

Cardiopulmonary arrest is a medical emergency in which the lapse of time between event onset and the initiation of measures of basic and advanced support, as well as the correct care based on specific protocols for each clinical situation, constitute decisive factors for a successful therapy. Cardiopulmonary arrest care cannot be restricted to the hospital setting because of its fulminant nature. This necessitates the creation of new concepts, strategies and structures, such as the concept of life chain, cardio-pulmonary resuscitation courses for professionals who work in emergency medical services, the automated external defibrillator, the implantable cardioverter-defibrillator, and mobile intensive care units, among others. New concepts, strategies and structures motivated by new advances have also modified the treatment and improved the results of cardiopulmonary resuscitation in the hospital setting. Among them, we can cite the concept of cerebral resuscitation, the application of the life chain, the creation of the universal life support algorithm, the adjustment of drug doses, new techniques - measure of the end-tidal carbon dioxide levels and of the coronary perfusion pressure - and new drugs under research.

Influence of the elevation of the left ventricular diastolic pressure on the values of the first temporal derivative of the ventricular pressure (dP/dt)

PURPOSE: To assess the effects of the elevation of the left ventricular end-diastolic pressure (LVEDP) on the value of the 1st temporal derivative of the ventricular pressure (dP/dt). METHODS: Nineteen anesthetized dogs were studied. The dogs were mechanically ventilated and underwent thoracotomy with parasympathetic nervous system block. The LVEDP was controlled with the use of a perfusion circuit connected to the left atrium and adjusted to the height of a reservoir. The elevation of the LVEDP was achieved by a sudden increase in the height of a reservoir filled with blood. Continuous recordings of the electrocardiogram, the aortic and ventricular pressures and the dP/dt were performed. RESULTS: Elevation of the LVEDP did not result in any variation of the heart rate (167±16.0bpm, before the procedure; 167±15.5bpm, after the procedure). All the other variables assessed, including systolic blood pressure (128±18.3mmHg and 150±21.5mmHg), diastolic blood pressure (98±16.9mmHg and 115±19.8mmHg), LVEDP (5.5±2.49 and 9.3±3.60mmHg), and dP/dt (4,855 ± 1,082 mmHg/s and 5,149±1,242mmHg/s) showed significant increases following the expansion of the ventricular cavity. Although the elevation of the dP/dt was statistically significant, 6 dogs curiously showed a decrease in the values of dP/dt. CONCLUSION: Sudden elevation of the LVEDP resulted in increased values of dP/dt; however, in some dogs, this response was not uniform.

Unsupported valvuloplasty in children with congenital mitral valve anomalies. Late clinical results

OBJECTIVE: To analyze late clinical evolution after surgical treatment of children, with reparative and reconstructive techniques without annular support. METHODS: We evaluated 21 patients operated upon between 1975 and 1998. Age 4.67±3.44 years; 47.6% girls; mitral insufficiency 57.1% (12 cases), stenosis 28.6% (6 cases), and double lesion 14.3% (3 cases). The perfusion 43.10±9.50min, and ischemia time were 29.40±10.50min. The average clinical follow-up in mitral insufficiency was 41.52±53.61 months. In the stenosis group (4 patients) was 46.39±32.02 months, and in the double lesion group (3 patients), 39.41±37.5 months. The echocardiographic follow-up was in mitral insufficiency 37.17±39.51 months, stenosis 42.61±30.59 months, and in the double lesion 39.41±37.51 months. RESULTS: Operative mortality was 9.5% (2 cases). No late deaths occurred. In the group with mitral insufficiency, 10 (83.3%) patients were asymptomatic (p=0.04). The majorit y with mild reflux (p=0.002). In the follow-up of the stenosis group, all were in functional class I (NYHA); and the mean transvalve gradient varied between 8 and 12mmHg, average of 10.7mmHg. In the double lesion group, 1 patient was reoperated at 43 months. No endocarditis or thromboembolism were reported. CONCLUSION: Mitral stenosis repair has worse late results, related to the valve abnormalities and associated lesions. The correction of mitral insufficiency without annular support showed good long-term results.

Fontan Operation and the Cavopulmonary Technique: Immediate and Late Results According to the Presence of Atrial Fenestration

OBJECTIVE: To compare immediate and late results in patients with or without fenestration who underwent cavopulmonary anastomosis so that we could assess the efficiency of the technique. METHODS: Sixty-two patients underwent surgery between 1988 and 1999, 41 with fenestration (group I -G I) and 21 without fenestration (group II -G II). Tricuspid atresia was prevalent in group I (23-56%) and single ventricle was prevalent in group II (14-66%). Mean ages at the time of operation were 7.3 years in group I and 7.6 in group II. At late follow-up, mean ages were 10.6 years in group I and 12.8 years in group II. RESULTS: Immediate and late mortality were 7.3% in G-I and 4.7% in G-II. Significant pleural effusion occurred in 41.4% of G-I patients and in 23.8% of G-II patients. Significant pericardial effusion occurred in 29.2% and 14.2%, respectively, in groups I and II. Central venous pressure was greater in G-II, 17.7 cm in H2O, as opposed to 15 cm in G-I. Hospital stay was similar between the groups, 26.3 and 21.8 days, respectively. Cyanosis and arterial insaturation occurred in 5 patients, and 4 patients were in functional class II, all from G-I. At late follow-up, 58 (93.5%) were in functional class I. Sinus rhythm was present in 94%, and pulmonary perfusion was similar in both groups. Eleven patients who underwent spirometry had good tolerance to physical effort. CONCLUSION: Atrial fenestration did not improve the immediate or late follow-up of patients who underwent cavopulmonary anastomosis, and is, therefore, dispensable.

Study of Coronary Flow Reserve with Intravenous Use of Microbubbles (Contrast Echocardiography) and Adenosine: Protocol for Clinical Application in Patients Suspected of Having Coronary Heart Disease

OBJECTIVE: To test the feasibility, safety and accuracy of the adenosine protocol in the study of myocardial perfusion with microbubbles contrast echocardiography. METHODS: 81 pts (64 male, 60+11 years) were submitted to contrast echocardiography with PESDA (sonicated solution of albumin 20%-1ml, dextrose 5%-12ml and deca-fluorobutane gas-8ml) to study the myocardial perfusion at rest and after bolus injection of adenosine (6 to 18mg) and to coronary angiography within 1 month each other. For each patient 3 left ventricle perfusion beds were considered (total of 243 territories). 208 territories were analyzed and 35 territories were excluded. PESDA was continuously infused (1-2ml/min), titrated for best myocardial contrast. Triggered (1:1) second harmonic imaging was used. RESULTS: Coronary angiography showed 70 flow limiting (> 75%) lesions and 138 no flow limiting lesions. At rest an obvious myocardium contrast enhancement was seen in at least 1 segment of a territory in all patients. After adenosine injection an unquestionable further increase in myocardial contrast was observed in 136 territories (99%) related to no flow limiting lesions, lasting < 10 s, and a myocardial perfusion defect was detected in 68 territories (97%) related to flow limiting lesions. It was observed only 4 false results. There were no serious complications. CONCLUSION: Myocardial perfusion study with PESDA and adenosine protocol is a practical, safe and accurate method to analyze the coronary flow reserve.

Subendocardial fibrosis in remote myocardium results from reduction of coronary driving pressure during acute infarction in rats

OBJECTIVE: To investigate the role of hemodynamic changes occurring during acute MI in subsequent fibrosis deposition within non-MI. METHODS: By using the rat model of MI, 3 groups of 7 rats each [sham, SMI (MI <30%), and LMI (MI >30%)] were compared. Systemic and left ventricular (LV) hemodynamics were recorded 10 minutes before and after coronary artery ligature. Collagen volume fraction (CVF) was calculated in picrosirius red-stained heart tissue sections 4 weeks later. RESULTS: Before surgery, all hemodynamic variables were comparable among groups. After surgery, LV end-diastolic pressure increased and coronary driving pressure decreased significantly in the LMI compared with the sham group. LV dP/dt max and dP/dt min of both the SMI and LMI groups were statistically different from those of the sham group. CVF within non-MI interventricular septum and right ventricle did not differ between each MI group and the sham group. Otherwise, subendocardial (SE) CVF was statistically greater in the LMI group. SE CVF correlated negatively with post-MI systemic blood pressure and coronary driving pressure, and positively with post-MI LV dP/dt min. Stepwise regression analysis identified post-MI coronary driving pressure as an independent predictor of SE CVF. CONCLUSION: LV remodeling in rats with MI is characterized by predominant SE collagen deposition in non-MI and results from a reduction in myocardial perfusion pressure occurring early on in the setting of MI.

Effects of high glucose concentrations on the endothelial function of the renal microcirculation of rabbits

OBJECTIVE: To assess the acute effects of high glucose concentrations on vascular reactivity in the isolated non diabetic rabbit kidney. METHODS: Rabbits were anaesthetized for isolation of the kidneys. Renal arteries and veins were cannulated for perfusion with Krebs-Henselleit solution and measurement of perfusion pressure. After 3 hours of perfusion with glucose 5,5 mM (control ) and 15 mM, the circulation was submitted to sub maximal precontraction (80% of maximal response) trough continuous infusion of noradrenaline 10 mM. Vascular reactivity was then assessed trough dose-responses curves with endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) vasodilators. The influence of hyperosmolarity was analyzed with perfusion with mannitol 15mM. RESULTS: A significant reduction in the endothelium-dependent vasodilation in glucose 15mM group was observed compared to that in control, but there was no difference in endothelium-independent vasodilation. After perfusion with mannitol 15 mM, a less expressive reduction in endothelium-dependent vasodilation was observed, only reaching significance in regard to the greatest dose of acetylcholine. CONCLUSION: High levels of glucose similar to those found in diabetic patients in the postprandial period can cause significant acute changes in renal vascular reactivity rabbits. In diabetic patients these effects may also occur and contribute to diabetes vascular disease.

Anomalous origin of the left coronary artery from the pulmonary trunk in a 45-year-old woman

We report a rare case of anomalous origin of the left coronary artery from the pulmonary trunk in a 45-year-old woman. The approach and technique used for selective catheterization of an anomalous left coronary artery arising from the pulmonary trunk are described. Six years after diagnosis, echocardiography showed left ventricular disfunction, and surgical treatment was indicated again. The origin of the left coronary artery from the pulmonary trunk was closed, and the postoperative period was uneventful, with recovery of left ventricular function and disappearance of ischemic features on stress myocardial perfusion imaging with 99m Tc-sestamibi, performed 4 weeks after surgery.

Clinical significance of transient left ventricular dilation assessed during myocardial Tc-99m sestamibi scintigraphy

OBJECTIVE: To assess the clinical significance of transient ischemic dilation of the left ventricle during myocardial perfusion scintigraphy with stress/rest sestamibi. METHODS: The study retrospectively analyzed 378 patients who underwent myocardial perfusion scintigraphy with stress/rest sestamibi, 340 of whom had a low probability of having ischemia and 38 had significant transient defects. Transient ischemic dilation was automatically calculated using Autoquant software. Sensitivity, specificity, and the positive and negative predictive values were established for each value of transient ischemic dilation. RESULTS: The values of transient ischemic dilation for the groups of low probability and significant transient defects were, respectively, 1.01 ± 0.13 and 1.18 ± 0.17. The values of transient ischemic dilation for the group with significant transient defects were significantly greater than those obtained for the group with a low probability (P<0.001). The greatest positive predictive values, around 50%, were obtained for the values of transient ischemic dilation above 1.25. CONCLUSION: The results suggest that transient ischemic dilation assessed using the stress/rest sestamibi protocol may be useful to separate patients with extensive myocardial ischemia from those without ischemia.

Disfunção erétil: um marcador para alterações da perfusão miocárdica?

OBJETIVO: Investigar a correlação entre alterações da perfusão miocárdica e a presença de disfunção erétil (DE) em homens com suspeita clínica ou diagnóstico já estabelecido de insuficiência coronariana crônica. MÉTODOS: Estudo prospectivo com 287 pacientes que, após responderem o questionário IIEF-5 para diagnóstico e avaliação do grau de DE, foram submetidos a avaliação clínico-cardiológica e a estudo cintilográfico da perfusão miocárdica (tecnécio - 99m sestamibi - gated SPECT), antes e após estresse físico ou farmacológico. RESULTADOS: Em 137 pacientes (47,8%) foi detectado algum grau de disfunção erétil (grupo DE+) e nestes, a idade (60,60±9,84 vs 50,67±9,94 - p<0,001)) foi significativamente maior do que naqueles sem disfunção (grupo DE-). No grupo DE+ houve maior prevalência de hipertensão arterial, diabetes, infarto do miocárdio e coronarioplastia prévios. Independentemente do fator idade, o grupo DE+ teve maior prevalência de alterações da perfusão miocárdica (necrose e/ou isquemia) e de diminuição da mobilidade e do grau de espessamento sistólico do miocárdio ventricular. CONCLUSÃO: Pacientes com DE tem maior probabilidade de apresentar alterações da perfusão e do desempenho miocárdico segmentar, independentemente do fator idade. Na presente amostra, a DE foi considerada não só como um marcador da doença isquêmica do coração, mas também fortemente relacionada à ocorrência de eventos coronarianos maiores como infarto do miocárdio e necessidade de coronarioplastia.

Doença arterial coronariana em diabéticas do tipo 2 assintomáticas: estudo comparativo entre o teste ergométrico, o teste cardiopulmonar e a cintilografia de perfusão miocárdica com dipiridamol na identificação de isquemia

FUNDAMENTO: A doença cardiovascular é a principal causa de morbi-mortalidade nos diabéticos. A isquemia do miocárdio é freqüentemente assintomática levando ao diagnóstico tardio e pior prognóstico. Sabe-se que a mulher diabética tem risco de morte cardiovascular maior em relação ao sexo masculino. OBJETIVO: Avaliar a prevalência de doença arterial coronariana (DAC) em diabéticas assintomáticas. Comparar os resultados do teste ergométrico (TE), do teste cardiopulmonar (TCP) e da cintilografia do miocárdio sob estímulo farmacológico com dipiridamol (CM) com os achados da cinecoronariografia (CINE) verificando o método de maior acurácia na identificação de DAC significativa. MÉTODOS: Foram avaliadas 104 diabéticas que realizaram TE, TCP e CM no período de dois meses da CINE. As cintilografias com MIBI-99mTc foram realizadas pela técnica de gated-SPECT. A análise estatística foi realizada pelos testes x² de Pearson e t de Student, sendo realizada, ainda, análise de regressão logística. RESULTADOS: A prevalência de DAC no grupo estudado foi de 32,7%. No TE, o teste eficaz (p=0,045), a incompetência cronotrópica (p=0,031) e o tempo de esforço realizado (p=0,022) apresentaram associação significativa com DAC. No TCP, o VO2pico e a FC atingida apresentaram associação com DAC (p=0,004 e p=0,025). A maioria das variáveis da CM mostrou importante associação com DAC (todas com p=0,001). CONCLUSÃO: Os resultados obtidos sugerem elevada prevalência de DAC em pacientes diabéticas assintomáticas, devendo ser essa uma população investigada do ponto de vista cardiovascular. Dos métodos diagnósticos não-invasivos que foram empregados, o que mostrou ter maior poder de discriminação em relação às portadoras de DAC foi a CM com dipiridamol.

Miocárdio viável pela tomografia computadorizada com Tc-99m (MIBI) sensibilizada por nitroglicerina endovenosa

FUNDAMENTO: A seleção de pacientes com doença coronariana crônica para recanalização baseia-se na detecção do miocárdio comprometido, potencialmente viável. OBJETIVO: Avaliar o miocárdio isquêmico, potencialmente viável pelo SPECT com MIBI sensibilizado por nitroglicerina em dose máxima tolerada. MÉTODOS: Investigamos de forma prospectiva, de abril de 2004 a novembro de 2005, pela tomografia computadorizada por emissão de fóton único SPECT com Tc-99m (MIBI), 40 pacientes (média etária 62 ± 8,9 anos, 30 homens) com obstrtução coronariana demonstrada angiograficamente, e a cintilografia miocárdica foi realizada em repouso e com nitroglicerina endovenosa (EV), iniciando com a dose (1 µg/kg/min) e incremento a cada minuto, até a queda da pressão arterial sistólica em 20 mmHg. A redução da perfusão dos segmentos foi classificada em moderada e severa, e comparada depois da nitroglicerina. Analisamos as variáveis angiográficas, hemodinâmicas e de perfusão miocárdica. RESULTADOS: Analisamos 680 segmentos miocárdicos em repouso: 538 com distribuição homogênea e 142 com hipoperfusão (54 com redução moderada e 88 severa). Depois da nitroglicerina, ocorreu aumento da perfusão em 19 (47,5%) de 40 pacientes. Tornaram-se viáveis 55 de 142 segmentos: 33 (61,1%) com redução moderada e 22 (25%) com redução severa, ambos apresentaram aumento significativo da distribuição do radiofármaco (p < 0,001, qui-quadrado). CONCULSÃO: Dos componentes com Tc-99m, está incluído o Tc-99m-2-methoxy-isobutil-isonitrila (MIBI) que, utilizado com dose otimizada de nitroglicerina EV, pode aumentar a captação do radiofármaco em áreas com hipoperfusão moderada e severa. Os resultados deste estudo sugerem aumento da sensibilidade do Tc-99m (MIBI) pela nitroglicerina para detecção de miocárdio viável.

Infarto do miocárdio causado por lesão arterial coronariana após trauma torácico fechado

Relatamos o caso de um indivíduo do sexo masculino de 29 anos de idade, vítima de um acidente de carro no qual sofreu trauma torácico fechado, evoluindo com insuficiência cardíaca congestiva. O paciente apresentava boa saúde previamente, sem sintomas de doença cardiovascular. Na avaliação inicial, o eletrocardiograma mostrou ondas Q nas derivações precordiais e o ecocardiograma mostrou disfunção ventricular esquerda importante. A angiografia coronária mostrou uma lesão na artéria coronária descendente anterior esquerda (ADE), com acinesia da parede anterior na ventriculografia com contraste. A tomografia computadorizada por emissão de fóton único (SPECT) com Tálio-201 não mostrou viabilidade. O paciente foi mantido em tratamento clínico com boa evolução.