neurally mediated hypotension

BACKGROUND: Swallow or deglutition syncope is an unusual type of neurally-mediated syncope associated with life-threatening bradyarrhythmia and hypotension. It is a difficult condition to diagnose with commonly delayed diagnosis and management. There is lack of review articles that elucidate the basic demographics, clinical characteristics and management of this rare condition. This publication systematically reviews the 101 case reports published since 1793 on swallow syncope. CASE PRESENTATION: A 59-year-old man presented with the complaint of recurrent dizziness associated with meals...

Patients with severe myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS) experience debilitating physical and cognitive symptoms, which often result in the need to file disability claims. A significant number of ME/CFS patients are children or adolescents. ME/CFS patients often turn to physicians who are not trained to recognize and diagnose ME/CFS, and who might or might not understand that ME/CFS is a multi-system primarily physical illness. Such misperceptions can adversely affect the doctor-patient relationship, the clinical outcomes, as well as the results of disability claims...

This perspective piece on head-up tilt table testing is part of a series on autonomic function testing. The tilt table can be a useful diagnostic test, but methodologies vary, and the results are sometimes misinterpreted. The intent here is not to review comprehensively the utility of various tilt table testing protocols but to convey a number of general points that may give perspective and have practical clinical value, based on an understanding of autonomic physiology and our long clinical and research experience in the evaluation of autonomic disorders...

Introduction: Cardiovascular complications in patients with subarachnoid hemorrhage are considered to be a neurally mediated process rather than a manifestation of coronary artery disease. Aim: The aim of study is to show the incidence and type cardiac complications after traumatic and spontaneous SAH. Patients and methods: The study had prospective character in which included 104 patients, with diagnosed subarachnoid hemorrhage (SAH), in the period from 2014 to 2017...

Autonomic complaints are frequently encountered in clinical practice. They can be due to primary autonomic disorders or secondary to other medical conditions. Primary autonomic disorders can be categorized as orthostatic intolerance syndromes and small fiber neuropathies; the latter are associated with autonomic failure, pain, or their combinations. The review outlines orthostatic intolerance syndromes (neurally mediated syncope, orthostatic hypotension, postural tachycardia syndrome, inappropriate sinus tachycardia, orthostatic cerebral hypoperfusion syndrome, and hypocapnic cerebral hypoperfusion) and small fiber neuropathies (sensory/autonomic/mixed, acute/subacute/chronic, idiopathic/secondary, inflammatory and noninflammatory)...

Severe hemorrhagic shock induces cognitive dysfunction by promoting cell death mediated by activating endoplasmic reticulum (ER) stress. Sevoflurane postconditioning prevents neuronal apoptosis against cerebral ischemia/reperfusion injury. It is unknown if this protective effect on hemorrhagic shock and resuscitation rats (HSR) is associated with ER stress attenuation. Male adult Sprague-Dawley rats were subjected HSR by removing 40% blood volume within 30 min, and 60 min later the animals were resuscitated with infusion of the removing blood in 30 min...

PURPOSE OF REVIEW: We review the literature on co-occurrence of syncope and headache and share clinical experience. RECENT FINDINGS: Headache in relation to syncope has been the subject of recent interest. Orthostatic intolerance has an expanding spectrum with three well-defined entities: orthostatic hypotension (OH), neurally mediated hypotension (NMH), and postural tachycardia syndrome (PoTS). Syncope occurs in patients with OH as well as in patients with episodically occurring NMH...

Neuroimmune communication, the connection between the autonomic regulatory pathway and immune cells, has been implicated in the regulation of immune function and inflammation. The role of afferents (vagal afferent and somatic sensory nerves) and efferents (autonomic nervous and hypothalamic-pituitary-adrenal systems) in the inflammatory reflex has been well studied; however, the central pathway remains unknown. C1 neurons include both catecholaminergic and glutamatergic neurons, which are located in the rostral ventrolateral medulla...

Syncope is a prevalent health problem among elderly people. It may be neurally mediated or caused by conditions such as orthostatic hypotension, postprandial hypotension, and cardiac disorders. A combination of different aetiologies is not uncommon in the elderly people. Many pathophysiological processes, including age-related physiological changes, co-morbidities, concomitant medication use, and prolonged bedrest, coexist and predispose elderly people to syncope; advanced age and cardiac syncope are associated with increased mortality...

The most frequent cause of syncope in young athletes is noncardiac etiology. The mechanism of noncardiac syncope (NCS) in young athletes is neurally-mediated (reflex). NCS in athletes usually occurs either as orthostasis-induced, due to a gravity-mediated reduced venous return to the heart, or in the context of exercise. Exercise-related NCS typically occurs after the cessation of an exercise bout, while syncope occurring during exercise is highly indicative of the existence of a cardiac disorder. Postexercise NCS appears to result from hypotension due to impaired postexercise vasoconstriction, as well as from hypocapnia...

Oxycodone is a semi-synthetic opioid drug that is used to alleviate acute and chronic pain. However, oxycodone is often abused and, when taken at high doses, can induce powerful CNS depression that manifests in respiratory abnormalities, hypotension, coma, and death. Here, we employed several techniques to examine the effects of intravenous oxycodone at a wide range of doses on various metabolism-related parameters in awake, freely-moving rats. High-speed amperometry was used to assess how oxycodone affects oxygen and glucose levels in the nucleus accumbens (NAc)...

PURPOSE: Individuals predisposed to vasovagal syncope may have different autonomic nervous system control mechanisms from those without predisposition to vasovagal events. To test this hypothesis, we investigated different sympathetic responses in a canine model of vasovagal syncope. METHODS: Left thoracotomy was performed on 20 mongrel dogs. The heart was exposed and a bolus of veratridine (15 μg/kg), a neurotoxin which prevents the inactivation of sodium ion channels, was injected into the left atrium to induce a Bezold-Jarisch reflex-mediated vasovagal event, characterized by bradycardia, decreased inotropism, and hypotension...

Syncope is defined as a sudden transient loss of consciousness (TLOC) with concomitant loss of postural tone followed by spontaneous recovery. It is a subset of a broader class of medical conditions, including postural orthostatic tachycardia syndrome (POTS), orthostatic hypotension, and neurally mediated syncope (NMS), that may result in TLOC. The overlap of these clinical conditions leads to confusion regarding syncope classification that can hinder evaluation strategies, and pose challenges for diagnosis and treatment, particularly in young women...

Syncope is a common emergency of children and adolescents, which has serious influence on the quality of life. Neurally-mediated syncope, including postural tachycardia syndrome, vasovagal syncope, orthostatic hypotension and orthostatic hypertension, is the main cause of syncope in children and adolescents. The main manifestations of neurally-mediated syncope are diverse, such as dizziness, headache, chest tightness, chest pain, pale complexion, fatigue, pre-syncope and syncope. Although the clinical manifestations are similar, each subtype of syncope has its hemodynamic feature and optimal treatment option...

INTRODUCTION: Orthostatic hypotension is defined as a sustained decrease in systolic blood pressure of 20 mm Hg or a decrease in diastolic blood pressure of 10 mm Hg within three minutes of standing compared with blood pressure from the sitting or supine position or by head-up tilt-table testing (1). When sustained blood pressure (BP) drop is after three minutes of upright posture it is called delayed orthostatic hypotension (delayed OH) (2). AIM OF THE STUDY: To detect the incidence of delayed orthostatic hypotension in patients referred to our autonomic lab...

Syncope is an abrupt and transient loss of consciousness caused by cerebral hypoperfusion. It accounts for 1% to 1.5% of emergency department visits, resulting in high hospital admission rates and significant medical costs. Syncope is classified as neurally mediated, cardiac, and orthostatic hypotension. Neurally mediated syncope is the most common type and has a benign course, whereas cardiac syncope is associated with increased morbidity and mortality. Patients with presyncope have similar prognoses to those with syncope and should undergo a similar evaluation...

Autonomic dysfunction contributes to health-related impairment of quality of life in the hypermobile type of Ehlers-Danlos syndrome (hEDS). Typical signs and symptoms include tachycardia, hypotension, gastrointestinal dysmotility, and disturbed bladder function and sweating regulation. Cardiovascular autonomic dysfunction may present as Orthostatic Intolerance, Orthostatic Hypotension, Postural Orthostatic Tachycardia Syndrome, or Neurally Mediated Hypotension. The incidence, prevalence, and natural history of these conditions remain unquantified, but observations from specialist clinics suggest they are frequently seen in hEDS...

I report a case of hypotension and bradycardia before spinal anesthesia in a pregnant woman with mild to moderate hypertension treated with nifedipine and methyldopa, scheduled for an elective cesarean delivery. She had the history of neurally-mediated syncopes. Two main factors (increased vagal tone and adverse effects of antihypertensive drugs) could explain the hypotension and bradycardia before spinal anesthesia. Monitoring allowed recognizing the problem and corrected it. Thus, it was avoided a disaster in anesthesia, as hemodynamic changes after spinal anesthesia, they would have joined to previous hypotension and bradycardia, which would have caused even a cardiac arrest...

Blood pressure regulation is known to be maintained by a neuro-endocrine circuit, but whether immune cells contribute to blood pressure homeostasis has not been determined. We previously showed that CD4(+) T lymphocytes that express choline acetyltransferase (ChAT), which catalyzes the synthesis of the vasorelaxant acetylcholine, relay neural signals. Here we show that these CD4(+)CD44(hi)CD62L(lo) T helper cells by gene expression are a distinct T-cell population defined by ChAT (CD4 TChAT). Mice lacking ChAT expression in CD4(+) cells have elevated arterial blood pressure, compared to littermate controls...

BACKGROUND: Alcohol is a known triggering factor for orthostatic dysfunction, increasing the risk of neurally-mediated syncope. Since orthostatic tolerance may be affected by both systemic and cerebral hemodynamic changes, our aim was to investigate the acute effects of alcohol on cerebral vasoreactivity measured during the head-up tilt (HUT) test in 20 healthy subjects. METHODS: Mean arterial blood pressure (mBP), heart rate, and flow parameters in both middle cerebral arteries (MCAs) were continuously recorded in the supine and during a 10-minute HUT positions before and after alcohol intake...