Demystifying airline syncope

Syncope forms a major part of medical in-flight emergencies contributing one-in-four in-flight medical events accounting to 70% of flight diversions. In such patients, it is important to elucidate the pathophysiology of syncope prior to diversion. Postural hypotension is the most common etiology of in-flight syncopal events. However, individuals without any underlying autonomic dysfunction can still experience syncope from hypoxia also known as airline syncope. Initial steps in managing such patients include positioning followed by the airway, breathing and circulation of resuscitation. These interventions need to be in close coordination with ground control to determine decision for flight diversion. Interventions which have been tried for prevention include mental challenge and increased salt and fluid intake. The current paper enhances the understanding of airline syncope by summarizing the associated pathophysiologic mechanisms and the management medical personnel can initiate with limited resources.     

JAK2‐positive cutaneous myelofibrosis presenting as sclerosing extramedullary hematopoietic tumors on the scalp: case presentation and review of the literature

We report the second case of cutaneous myelofibrosis with a documented JAK2 activating mutation involving the scalp of a 67‐year‐old woman with primary myelofibrosis in her marrow. In contrast to the previous case, the biopsy revealed extensive lesional collagen deposition and closely mimicked a fibrohistiocytic proliferation. Similar rare lesions occurring in the setting of myeloproliferative neoplasms have been called sclerosing extramedullary hematopoietic tumors. These entities appear histomorphologically and etiologically distinct from extramedullary hematopoiesis, and their diagnosis should prompt the workup for a myeloproliferative neoplasm in the absence of an antecedent diagnosis. The presence of the JAK2 mutation in our case confirmed that the lesions represented skin involvement by a neoplastic myeloid proliferation and not compensatory extramedullary hematopoiesis. Our patient died of disease several months following the appearance of her lesions, which is in keeping with other reports that suggest that cutaneous myelofibrosis may serve as an independent poor prognostic sign in otherwise advanced primary myelofibrosis. A review of the literature further emphasizes the importance of distinguishing this entity from mesenchymal neoplasms and acute myeloid leukemia involving the skin.     

Are sperm capacitation and apoptosis the opposite ends of a continuum driven by oxidative stress?

This chapter explores the possibility that capacitation and apoptosis are linked processes joined by their common dependence on the continued generation of reactive oxygen species (ROS). According to this model capacitation is initiated in spematozoa following their release into the female reproductive tract as a consequence of intracellular ROS generation, which stimulates intracellular cAMP generation, inhibits tyrosine phosphatase activity and enhances the formation of oxysterols prior to their removal from the sperm surface by albumin. The continued generation of ROS by capacitating populations of spermatozoa eventually overwhelms the limited capacity of these cells to protect themselves from oxidative stress. As a result the over-capacitation of spermatozoa leads to a state of senescence and the activation of a truncated intrinsic apoptotic cascade characterized by enhanced mitochondrial ROS generation, lipid peroxidation, motility loss, caspase activation and phosphatidylserine externalization. The latter may be particularly important in instructing phagocytic leukocytes that the removal of senescent, moribund spermatozoa should be a silent process unaccompanied by the generation of proinflammatory cytokines. These observations reveal the central role played by redox chemistry in defining the life and death of spermatozoa. A knowledge of these mechanisms may help us to engineer novel solutions to both support and preserve the functionality of these highly specialized cells.     

Spontaneous Coronary Artery Dissection with Cardiac Tamponade

Spontaneous coronary artery dissection is a rare cause of acute coronary syndrome. Clinical presentation ranges from chest pain alone to ST-segment-elevation myocardial infarction, ventricular fibrillation, and sudden death. The treatment of patients with spontaneous coronary artery dissection is challenging because the disease pathophysiology is unclear, optimal treatment is unknown, and short- and long-term prognostic data are minimal.We report the case of a 70-year-old woman who presented with an acute ST-segment-elevation myocardial infarction secondary to a spontaneous dissection of the left anterior descending coronary artery. She was treated conservatively. Cardiac tamponade developed 16 hours after presentation. Repeat coronary angiography revealed extension of the dissection. Medical therapy was continued after the hemopericardium was aspirated. The patient remained asymptomatic 3 years after hospital discharge. To our knowledge, this is the first reported case of spontaneous coronary artery dissection in association with cardiac tamponade that was treated conservatively and had a successful outcome.     

Fetal and Neonatal Imaging and Strategy of Primary Neonatal Heart Transplantation in Hypoplastic Left Heart with Ebstein's Anomaly

We present the anatomic constellation of mitral stenosis/aortic atresia variant of hypoplastic left heart syndrome, Ebstein's anomaly, and partial anomalous pulmonary venous return, an exceeding rare congenital heart defect. Prenatal echocardiography led to concern about the capacity of the right ventricle to increase cardiac output with lung expansion and pulmonary arterial runoff at birth, prompting the precaution of extracorporeal membrane oxygenator standby at delivery. Stage I palliation was not attempted, and control of pulmonary arterial blood flow was achieved with pulmonary artery banding, allowing sufficient ongoing hemodynamic stability. Orthotopic cardiac transplantation, repair of hypoplastic aortic arch, and primary sutureless repair of left pulmonary veins was performed, using dual‐site arterial cannulation and continuous mild hypothermic cardiopulmonary bypass. We discuss how this unique echocardiographic anatomy influenced the surgical decision and point out how it guided therapy toward a strategy of primary transplantation rather than standard staged surgical palliation.