Neurologic complications of lightning injuries.

Over the past ten years, we have cared for 13 patients who suffered serious neurologic complications after being struck by lightning. The spectrum of neurologic lesions includes the entire neuraxis from the cerebral hemispheres to the peripheral nerves. We describe these various neurologic disorders with regard to the site of the lesion, severity of the deficit, and the outcome. Damage to the nervous system can be a serious problem for patients struck by lightning. Fatalities are associated with hypoxic encephalopathy in patients who suffered cardiac arrests. Patients with spinal cord lesions are likely to have permanent sequelae and paralysis. New technology for detecting lightning with wideband magnetic direction finders is useful in establishing lightning-flash densities in each state. Florida and the Gulf Coast states have the highest densities. Colorado and the Rocky Mountain states have the next highest.     

Exploring the association between extra-cardiac troponin elevations and risk of future mortality

Although the measurement of cardiac troponin I (cTnI) and T (cTnT) has now become the cornerstone for diagnosing cardiac injury, both ischemic and non-ischemic, recent evidence has become available that many patients display extra-cardiac causes of cTn elevations and carry a considerably enhanced risk of future mortality. The current literature data suggests that cTn elevations may be equally common in patients with cardiac and extra-cardiac diseases. Among the latter cohort of patients, the leading extra-cardiac diseases which may be responsible for either cTnI or cTnT elevations include infectious diseases/sepsis, pulmonary disorders, renal failure, malignancy, as well as gastrointestinal, neurological and musculoskeletal diseases. What also emerges rather clearly from the current literature data, is that the risk of dying for extra-cardiac diseases is higher (i.e., between two to three-fold) in patients with extra-cardiac cTn elevations than in those with cardiac pathologies, and that the most frequent cause of death would then be infections/sepsis, followed by malignancy, respiratory disorders, myocardial infarction, gastrointestinal and neurological diseases, heart failure, stroke, cardiac arrhythmias, renal failure, psychiatric, metabolic, urogenital and musculoskeletal disorders. These figures would lead to conclude that there is a considerable risk that the underlying pathology causing cardiac injury and cTn elevation would then become the cause of death in these patients. This important evidence shall lead the way to defining appropriate and effective strategies for managing patients with extra-cardiac cTn elevations, so that their risk of future death could be prevented or limited.     

Dating lightning: Dendrochronological and magnetic analyses of lightning scars

Lightning impacts on forests and trees are still understudied from a tree-ring perspective. Lighting causes direct and indirect damages on forests and trees. Trees struck by lightning can show a growth reduction and lightning storms also trigger wildfires in seasonally dry areas such as Mediterranean mountains. Here we combined dendroecological and magnetic analyses to reconstruct and assess the impact of lightning on radial growth and the magnetic properties of wood in Scots pine (Pinus sylvestris) and Black pine (Pinus nigra) in two sites with a high density of lightning impacts located in eastern Spain. We dated several lightning scars, particularly in Scots pine, formed during 1982, when a wildfire was initiated by lightning during a dry summer storm. Growth was reduced during the year when the scar was formed in both pine species, albeit this effect could be masked or amplified by other disturbances (drought, outbreaks). However, despite that short-term growth reduction scarred trees showed higher growth rates than non-scarred trees in the case of Scots pine. The intensity of magnetization did not significantly differ in wood produced before and after the lightning scar was formed. This could be due to multiple lightning hits in the same or nearby stands affecting the magnetization of wood. Wood magnetic properties should be further explored as proxies of lightning impacts in sites where scars are not formed and tree-ring information is limited such as tropical forests. Further cross-disciplinary research is required to assess the impacts of lightning on tree growth and magnetism.     

Why and how to support screening strategies to prevent sudden death in athletes

Sudden death in athletes occurs because of the existence of hidden cardiovascular disorders which, during effort, may jeopardize the electrical stability of the heart, triggering ventricular tachycardia and/or fibrillation. Apart from rare conditions of ion channel diseases in the setting of a structurally normal heart, in which the disorder may be easily diagnosed on basal or stress test ECG, cardiac abnormalities at risk of causing sudden death may affect the aorta (Marfan syndrome), the coronary arteries (congenital coronary artery anomalies, premature coronary atherosclerosis), the myocardium (hypertrophic and arrhythmogenic cardiomyopathy), the valves (bicuspid aortic valve, mitral valve prolapse) and the conduction system (pre-excitation syndromes). These structural heart disorders may be detected by ECG and/or echo. The employment of these tools at pre-participation screening can help to identify concealed anomalies, which may play a major role in early diagnosis, risk stratification, and prevention of sudden death.     

Effects of lightning on trees: A predictive model based on in situ electrical resistivity

The effects of lightning on trees range from catastrophic death to the absence of observable damage. Such differences may be predictable among tree species, and more generally among plant life history strategies and growth forms. We used field‐collected electrical resistivity data in temperate and tropical forests to model how the distribution of power from a lightning discharge varies with tree size and identity, and with the presence of lianas. Estimated heating density (heat generated per volume of tree tissue) and maximum power (maximum rate of heating) from a standardized lightning discharge differed 300% among tree species. Tree size and morphology also were important; the heating density of a hypothetical 10 m tall Alseis blackiana was 49 times greater than for a 30 m tall conspecific, and 127 times greater than for a 30 m tall Dipteryx panamensis. Lianas may protect trees from lightning by conducting electric current; estimated heating and maximum power were reduced by 60% (±7.1%) for trees with one liana and by 87% (±4.0%) for trees with three lianas. This study provides the first quantitative mechanism describing how differences among trees can influence lightning–tree interactions, and how lianas can serve as natural lightning rods for trees.     

Quantification and identification of lightning damage in tropical forests

Accurate estimates of tree mortality are essential for the development of mechanistic forest dynamics models, and for estimating carbon storage and cycling. However, identifying agents of tree mortality is difficult and imprecise. Although lightning kills thousands of trees each year and is an important agent of mortality in some forests, the frequency and distribution of lightning‐caused tree death remain unknown for most forests. Moreover, because all evidence regarding the effects of lightning on trees is necessarily anecdotal and post hoc, rigorous tests of hypotheses regarding the ecological effects of lightning are impossible. We developed a combined electronic sensor/camera‐based system for the location and characterization of lightning strikes to the forest canopy in near real time and tested the system in the forest of Barro Colorado Island, Panama. Cameras mounted on towers provided continuous video recordings of the forest canopy that were analyzed to determine the locations of lightning strikes. We used a preliminary version of this system to record and locate 18 lightning strikes to the forest over a 3‐year period. Data from field surveys of known lightning strike locations (obtained from the camera system) enabled us to develop a protocol for reliable, ground‐based identification of suspected lightning damage to tropical trees. In all cases, lightning damage was relatively inconspicuous; it would have been overlooked by ground‐based observers having no knowledge of the event. We identified three types of evidence that can be used to consistently identify lightning strike damage in tropical forests: (1) localized and directionally biased branch mortality associated with flashover among tree and sapling crowns, (2) mortality of lianas or saplings near lianas, and (3) scorched or wilting epiphytic and hemiepiphytic plants. The longitudinal trunk scars that are typical of lightning‐damaged temperate trees were never observed in this study. Given the prevalence of communications towers worldwide, the lightning detection system described here could be implemented in diverse forest types. Data from multiple systems would provide an outstanding opportunity for comparative research on the ecological effects of lightning. Such comparative data are increasingly important given expected increases in lightning frequency with climatic change.     

Manipulating the QT interval of the ECG by cognitive effort

Abnormal prolongation of the QT interval of the ECG has been reported to indicate a hazard of sudden arrhythmic death. Therefore, with the aid of biofeedback from a newly devised instrument capable of measuring and recording the QT interval of the ECG in real time, ten healthy subjects, aided by biofeedback, attempted to shorten and also to lengthen QT. Although the changes achieved were relatively small, the ten subjects as a group were successful in both shortening and lengthening QT at the 0.01 level of significance. The degree of success varied, however, from person to person and from time to time in the same individual. If the findings reported here can be applied more generally to patients at risk for sudden death, and if biofeedback effects can be made to persist without reinforcement, it or other cognitive techniques may prove clinically useful for shortening QT.     

Evaluation of B-type Natriuretic Peptide for validation of a heart failure register in primary care

Background

Studies suggest that Goal Directed Therapy (GDT) results in improved outcome following major surgery. However, there is concern that pre-emptive use of inotropic therapy may lead to an increased incidence of myocardial ischaemia and infarction.

Methods

Post hoc analysis of data collected prospectively during a randomised controlled trial of the effects of post-operative GDT in high-risk general surgical patients. Serum troponin T concentrations were measured at baseline and on day 1 and day 2 following surgery. Continuous ECG monitoring was performed during the eight hour intervention period. Patients were followed up for predefined cardiac complications. A univariate analysis was performed to identify any associations between potential risk factors for myocardial injury and elevated troponin T concentrations.

Results

GDT was associated with fewer complications, and a reduced duration of hospital stay. Troponin T concentrations above 0.01 μg l^-1 were identified in eight patients in the GDT group and six in the control group. Values increased above 0.05 μg l^-1 in four patients in the GDT group and two patients in the control group. There were no overall differences in the incidence of elevated troponin T concentrations. The incidence of cardiovascular complications was also similar. None of the patients, in whom troponin T concentrations were elevated, developed ECG changes indicating myocardial ischaemia during the intervention period. The only factor to be associated with elevated troponin T concentrations following surgery was end-stage renal failure.

Conclusion

The use of post-operative GDT does not result in an increased incidence of myocardial injury.     

Lightning Injury: Two Case Histories and a Review of Management

Two cases of fatal lightning injury are described. Fixed dilated pupils should not be taken as an indicator of death after a lightning strike. Persons who fail to breath spontaneously within one minute of lightning shock should receive external cardiac massage and mouth-to-mouth resuscitation. Paralysis may persist as result of cerebral oedema or prolonged hypoxia—it is therefore suggested that adequate ventilation and metabolic balance should be maintained until recovery or death.     

Cerebral venous sinus thrombosis after gender reassignment surgery

Background: Many factors have been implicated in the etiology of cerebral venous sinus thrombosis (CVT). These include head injury, cancer, infections (sepsis, sinusitis, and mastoiditis), coagulopathies, pregnancy, systemic lupus erythematosus, and dehydration.Case summary: We present the case of a patient who received long-term estrogen therapy for ~15 years after feminizing genitoplasty. The patient experienced a CVT with an excellent clinical outcome. A similar case has not been reported in the literature.Conclusion: Because CVT may be associated with morbidity, mortality, and risks from the complications and treatments of the condition, further research is needed to clarify the factors that may contribute to the long-term risk of CVT in patients receiving long-term estrogen therapy after feminizing genitoplasty.     

Malassezia Species: A Rare Cause of Invasive Fungal Infections in Immunocompromised Patients

The members of Malassezia species, which may cause skin disorders in healthy individuals, are associated with both cutaneous and systemic disorders in immunocompromised patients. These disorders include folliculitis, seborrheic dermatitis, catheter-related fungemia, and deeply invasive infections. This review examines not only the risk factors and pathogenesis of this rare fungal infection but also the clinical manifestations, diagnosis, and treatment of Malassezia infections in immunocompromised patients. Reports from several series of immunocompromised patients have shown low mortality rates with appropriate treatment.     

New aspects of ICD therapy: from rhythm therapy to complex cardiac monitoring. Development of an implantable, ICD-assisted, intrathoracic 6-channel ECG for continuous monitoring of high infarct risk patients]

Implantable defibrillator systems (ICD) are therapy of choice for the treatment of life-threatening ventricular arrhythmias and in prevention of sudden cardiac death. In more than 80% of patients who receive an ICD, the underlying cardiac disease is a coronary heart disease. Since arrhythmogenic sudden cardiac death can be reliably prevented in these patients by the use of ICD technology, the cardiac prognosis for these patients is determined by the occurrence of myocardial ischemia and myocardial infarction, as well as from the heart failure which develops in consequence. An intrathoracic 6-channel ECG comparable to the standard surface ECG can be reconstructed by further technical development of the electrode configurations currently present in ICD systems. The importance of this development in early diagnosis of myocardial ischemias and myocardial infarction can hardly be adequately estimated at the moment. The chronic consequences of myocardial infarction can be completely prevented or at least greatly reduced by means of such diagnostics and inclusion of immediate initiation of effective, appropriate early therapeutic measures before more serious symptoms even occur. In the development and pilot studies thus far, it has been found that the intrathoracic 6-channel ECG which can be generated in the ICD is capable of reliably recognizing acute myocardial ischemia, irrespective of localization or extent earlier and better than the standard surface ECG. Continuous preventive ischemia monitoring using the implanted ICD thus appears possible in patients at risk of infarction.     

The effect of a corona discharge on a lightning attachment

The interaction between the lightning leader and the space charge accumulated near the top of a ground object in the atmospheric electric field is considered using analytical and numerical models developed earlier to describe spark discharges in long laboratory gaps. The specific features of a nonstationary corona discharge that develops in the electric field of a thundercloud and a downward lightning leader are analyzed. Conditions for the development of an upward lightning discharge from a ground object and for the propagation of an upward-connecting leader from the object toward a downward lightning leader (the process determining the point of strike to the ground) are investigated. Possible mechanisms for the interaction of the corona space charge with an upward leader and prospects of using it to control downward lightning discharges are analyzed.     

Cardiac Arrhythmias In Congenital Heart Diseases

Arrhythmias figure prominently among the complications encountered in the varied and diverse population of patients with congenital heart disease, and are the leading cause of morbidity and mortality. The incidence generally increases as the patient ages, with multifactorial predisposing features that may include congenitally malformed or displaced conduction systems, altered hemodynamics, mechanical or hypoxic stress, and residual or postoperative sequelae. The safe and effective management of arrhythmias in congenital heart disease requires a thorough appreciation for conduction system variants, arrhythmia mechanisms, underlying anatomy, and associated physiology. We, therefore, begin this review by presenting the scope of the problem, outlining therapeutic options, and summarizing congenital heart disease-related conduction system anomalies associated with disorders of the sinus node and AV conduction system. Arrhythmias encountered in common forms of congenital heart disease are subsequently discussed. In so doing, we touch upon issues related to risk stratification for sudden death, implantable cardiac devices, catheter ablation, and adjuvant surgical therapy.     

Spatial and temporal variation in lightning ignitions in Sweden

Abstract. Analysis of fire statistics revealed that there are steep gradients in the distribution of lightning-caused fire ignitions in Sweden. The highest ignition density was found in the southeastern provinces of Kalmar and Östergötland, ca. 0.23/10 000 ha/yr. From there, densities generally declined both to the north and to the west, with a density averaging ca. 0.05 in the six northernmost provinces, and an equally low density in the southwestern province of Halland. For both northern and southern Sweden, lightning ignitions peaked in early July, but in the south the season for ignitions started 2–3 weeks earlier and ended 2–3 weeks later. The geographical gradients in lightning ignition density correspond to the average precipitation during summer. The patterns of lightning ignition densities may also indicate gradients in natural fire frequencies. This hypothesis is supported by the distribution of certain fire-adapted plant species.     

Recovery of the parameters of a lightning current pulse from measurements of the electromagnetic field in the far wave zone

A numerical model of the return stroke of a downward lightning is used to quantitatively analyze the error in recovering the parameters of a lightning current pulse from the electromagnetic field recorded in the far wave zone. It is shown that the error is mainly caused by the deformation of the current wave propagating along the plasma channel from the ground to the cloud and the dependence of the wave phase velocity on the current, rather than by the deviation of lighting from the vertical. The recovery error caused by the nonlinear dependence of the recorded magnetic field on the excitation current can reach a few hundred percent. Results of direct measurements of the lightning current at high-rise buildings and during trigger lightnings cannot be used to calibrate systems for remote monitoring of thunderstorm activity, because radiation from current-carrying metal structures substantially reduces the error caused by the damping of the return stroke wave in the plasma channel.     

Implantation of a completely right sided subcutaneous cardioverter-defibrillator in a patient with situs inversus dextrocardia

Dextrocardia is a congenital anomaly where the heart is abnormally located in the right hemithorax. In these patients, the implementation of transvenous implantable cardioverter-defibrillator (TV-ICD) can be technically challenging and pose a higher risk of complications than the general population. We present the case of a male patient that was successfully submitted to right-sided implantation of subcutaneous ICD (S-ICD) as an alternative to transvenous ICD (TV-ICD) for primary prevention of sudden cardiac death. This option is not only feasible but may potentially be ideal for these patients, as it circumvents challenges and potential complications of TV-ICD insertion.     

微血管减压术治疗面肌痉挛术后相关并发症的临床分析

目的:总结面肌痉挛患者的术后并发症的发生情况并分析其原因。方法:回顾性分析了1548名在我院行微血管减压术治疗面肌痉挛的患者的临床资料,所有患者接受电话随访或者门诊随访,随访时间均超过2年,总结其临床疗效及术后并发症的发生情况。结果:微血管减压术后痊愈率及明显缓解率分别为92.5%及4.2%。249名(16.09%)患者出现不同的并发症,其中最常见的并发症为面瘫及术后手术区域皮肤感觉障碍,无死亡及重大并发症患者。听力损害发生率为3.5%。其他并发症包括脑脊液漏、后组颅神经损伤、外展神经损伤、颅内出血等。结论:微血管减压术是治疗面肌痉挛的安全有效操作,以手术区域感觉障碍及迟发性面瘫是主要的并发症,持久性的或者严重的并发症比较少见。     

Arrhythmias after tetralogy of fallot repair

Tetralogy of Fallot is the most common cyanotic congenital heart disease, with a good outcome after total surgical correction. In spite of a low perioperative mortality and a good quality of life, late sudden death remains a significant clinical problem, mainly related to episodes of sustained ventricular tachycardia and ventricular fibrillation. Fibro-fatty substitution around infundibular resection, intraventricular septal scar, and patchy myocardial fibrosis, may provide anatomical substrates of abnormal depolarization and repolarization causing reentrant ventricular arrhythmias. Several non-invasive indices based on classical examination such as ECG, signal-averaging ECG, and echocardiography have been proposed to identify patients at high risk of sudden death, with hopeful results. In the last years other more sophisticated invasive and non-invasive tools, such as heart rate variability, electroanatomic mapping and cardiac magnetic resonance added a relevant contribution to risk stratification. Even if each method per se is affected by some limitations, a comprehensive multifactorial clinical and investigative examination can provide an accurate risk evaluation for every patient.     

Approach to the asymptomatic patients with Brugada syndrome

Brugada syndrome is an arrhythmogenic disease characterized by an ECG pattern of coved-type ST segment elevation in the right precordial leads and an increased risk of sudden cardiac death (SCD) as a result of polymorphic ventricular tachyarrhythmia or ventricular fibrillation (VF). Data from large patient studies and a meta-analysis of previous reports have shown that patients with a history of syncope or SCD and a spontaneous type 1 Brugada type ECG are at high risk for SCD. However, risk stratification of asymptomatic patients with Brugada type ECG is still a challenge. In particular, the use of electrophysiological study (EPS) for risk stratification remains controversial. Although some investigators have reported the possibility of use of EPS for distinguishing between high- and low-risk patients with Brugada type ECG, no precise predictor of risk for SCD in asymptomatic patients has yet been determined. The approach to treatment of these patients is thus still unclear. Large clinical prospective studies with uniform diagnostic criteria and protocols for EPS as well as extended follow-up periods of over ten years are required for prediction of SCD.