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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective was to determine the nature of autonomic and vasomotor changes in adolescent patients with orthostatic tachycardia associated with the chronic fatigue syndrome (CFS) and the postural orthostatic tachycardia syndrome (POTS). Continuous electrocardiography and arterial tonometry was used to investigate the heart rate and blood pressure responses before and 3-5 min after head-up tilt in 22 adolescents with POTS and 14 adolescents with CFS, compared with control subjects comprising 10 healthy adolescents and 20 patients with simple faint. Heart rate and blood pressure variability, determined baroreceptor function using transfer function analysis, and measured cardiac vagal and adrenergic autonomic responses were calculated using timed breathing and the quantitative Valsalva maneuver. Two of 10 healthy controls and 14 of 20 simple faint patients experienced vasovagal syncope during head-up tilt. By design, all CFS and POTS patients experienced orthostatic tachycardia, often associated with hypotension. R-R interval and heart rate variability were decreased in CFS and POTS patients compared with control subjects and remained decreased with head-up tilt. Low-frequency (0.05-0.15 Hz) blood pressure variability reflecting vasomotion was increased in CFS and POTS patients compared with control subjects and increased further with head-up tilt. This was associated with depressed baroreflex transfer indicating baroreceptor attenuation through defective vagal efferent response. Only the sympathetic response remained. Heart rate variability declined progressively from normal healthy control subjects through syncope to POTS to CFS patients. Timed breathing and Valsalva maneuver were most often normal in CFS and POTS patients, although abnormalities in select individuals were found. Heart rate and blood pressure regulation in POTS and CFS patients are similar and indicate attenuated efferent vagal baroreflex associated with increased vasomotor tone. Loss of beat-to-beat heart rate control may contribute to a destabilized blood pressure resulting in orthostatic intolerance. The dysautonomia of orthostatic intolerance in POTS and in chronic fatigue are similar.
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PMID:Autonomic nervous system dysfunction in adolescents with postural orthostatic tachycardia syndrome and chronic fatigue syndrome is characterized by attenuated vagal baroreflex and potentiated sympathetic vasomotion. 1092 98

Stimulated by the widespread use of head-up tilt testing, transient episodes of neurocardiogenically mediated hypotension and bradycardia have become a well recognized cause of recurrent syncope and near syncope (generally referred to as neurally mediated syncope). On the other hand, a large subgroup of patients was identified, who appeared to have a less severe hypotension and orthostatic intolerance that is characterized by postural tachycardia, exercise intolerance, disabling fatigue, lightheadedness and dizziness. This form of disability has been recognized as postural orthostatic tachycardia syndrome (POTS). While the etiology of POTS is still unclear, a mild form of idiopathic peripheral autonomic neuropathy (partial dysautonomia) or beta-receptor hypersensitivity has been suggested for the pathophysiology of this disorder. A detailed history and physical examination that includes a careful neurologic examination are essential for diagnosis. Head-up tilt testing is often useful as a standardized measure of response to postural change. This review summarizes the history, current knowledge of clinical features, diagnosis and therapeutic strategies.
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PMID:[Idiopathic postural orthostatic tachycardia syndrome] 1101 90

In recent years increased interest has focused on the nature and pathophysiology of orthostatic intolerance and syndromes associated with autonomic disorders. Understanding the pathophysiology underlying these syndromes has led to the recognition of several distinct clinical entities with overlapping features and the associated need to reclassify many of the previously unrecognized syndromes. Among the clinical manifestations, syncope and near syncope are frequently associated with orthostatic intolerance. In addition, however, a wide spectrum of symptoms have been described ranging from chronic fatigue to recurrent neurally mediated vasodepressor reactions. The present review focuses on the pathophysiology and classification of syndromes of autonomic dysfunction associated with orthostatic intolerance. Primary and secondary causes of dysautonomia as well as therapeutic approach to these frequently unrecognized syndromes is presented.
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PMID:[Autonomic dysfunction syndromes associated with orthostatic intolerance]. 1269 3

Chronic fatigue syndrome (CFS) is characterized by persistent mental and physical fatigue for at least 6 months. Its pathophysiology is unknown and there is no proven effective treatment. We describe three cases who fulfill the criteria of CFS, in whom a defect of neuromuscular transmission and dysautonomia are present and who respond to acetylcholine-esterase inhibition. Case 1: 18-year-old female with a 3-year history of CFS. Response of compound-muscle-action potential, recorded using surface recording electrode, over left abductor pollicis brevis muscle, to repetitive nerve stimulation (RNS) at a rate of 10 Hz showed a 42% incremental response. Composite autonomic scoring system (CASS) showed mild cholinergic impairment (cardiovagal score: 1; sudomotor score: 2). Serological tests for Epstein-Barr virus (EBV) revealed positive antiviral capsid antigens (anti-VCA) immunoglobulins G (IgG). Oral pyridostigmine therapy (30 mg) resulted in marked improvement in symptoms. Case 2: 28-year-old female with 10-year history of CFS. RNS, using identical protocol, showed a 60% incremental response over the same muscle. CASS showed mild cholinergic impairment (cardiovagal score: 1; sudomotor score: 2) and this patient was also positive for EBV. This patient responded dramatically to 10-mg pyridostigmine. Case 3: 29-year-old female with a history of CFS for longer than 15 years. Repetitive stimulation, using identical paradigm to left abductor pollicis brevis muscle, showed a 42% incremental response. CASS showed mildly cholinergic impairment (cardiovagal score: 2; sudomotor score: 1). EBV antibody titers were positive. Patient responded to 30-mg pyridostigmine with an improvement in her fatigue. These three cases generate the hypothesis that the fatigue in some patients with clinical CFS might be due to a combination of mild neuromuscular transmission defect combined with cholinergic dysautonomia. Support for this thesis derives from the improvement with cholinesterase inhibition.
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PMID:Efficacy of a half dose of oral pyridostigmine in the treatment of chronic fatigue syndrome: three case reports. 1456 34

The diagnosis of chronic fatigue syndrome (CFS) is based on patient history and treatment on cognitive behavior therapy and graded exercise. There is increasing evidence that dysautonomia occurs in CFS manifest primarily as disordered regulation of cardiovascular responses to stress. We impart our experience relating to diagnosis, monitoring, and treatment of CFS based on identification and management of dysautonomia. Recently proposed methods for assessment of the cardiovascular reactivity, the 'hemodynamic instability score' (HIS) and the 'Fractal and Recurrence Analysis-based Score' (FRAS), served for this purpose. On HUTT, a particular dysautonomia is revealed in CFS patients that differ from dysautonomia in several other disorders. This distinct abnormality in CFS can be identified by HIS >-0.98 (sensitivity 84.5% and specificity 85.1%) and FRAS > +0.22 (sensitivity 70% and specificity 88%). Therefore, the HIS and FRAS may be used, in the appropriate clinical context, to support the diagnosis of CFS, which until now, could only be subjectively inferred. A pilot study suggested that midodrine treatment, directed at the autonomic nervous system in CFS, results first in correction of dysautonomia followed by improvement of fatigue. This finding implies that dysautonomia is pivotal in the pathophysiology CFS, at least in a large part of the patients, and that manipulating the autonomic nervous system may be effective in the treatment of CFS.
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PMID:Dysautonomia in chronic fatigue syndrome: facts, hypotheses, implications. 1496 27

The long term results of midodrine treatment in a patient having debilitating chronic fatigue syndrome (CFS) are reported. Midodrine treatment, directed at the autonomic nervous system, resulted in correction of the dysautonomia followed by improvement of fatigue. This finding is consistent with the hypothesis that dysautonomia plays a major part in the pathophysiology of CFS and that therapies directed at the autonomic nervous system may be effective in the treatment of CFS.
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PMID:Midodrine treatment for chronic fatigue syndrome. 1508 46

Orthostatic intolerance affects an estimated 1 in 500 persons and causes a wide range of disabilities. After essential hypertension, it is the most frequently encountered dysautonomia, accounting for the majority of patients referred to centers specializing in autonomic disorders. Patients are typically young females with symptoms such as dizziness, visual changes, head and neck discomfort, poor concentration, fatigue, palpitations, tremulousness, anxiety, and, in some cases, syncope. Syncope is the most hazardous symptom of orthostatic intolerance, presumably occurring because of impaired cerebral perfusion and in part to compensatory autonomic mechanisms. The etiology of this syndrome is still unclear but is heterogeneous. Orthostatic intolerance used to be characterized by an overall enhancement of noradrenergic tone at rest in some patients and by a patchy dysautonomia of postganglionic sympathetic fibers with a compensatory cardiac sympathetic activation in others. However, recent advances in molecular genetics are improving our understanding of orthostatic intolerance, such as several genetic diseases (such as Ehler-Danlos syndrome and norepinephrine transporter deficiency) presenting with symptoms typical of orthostatic intolerance. Future work will include investigation of genetic functional mutations underlying interindividual differences in autonomic cardiovascular control, body fluid regulation, and vascular regulation in orthostatic intolerance patients. The goal of this review article is to describe recent advances in understanding the pathophysiological mechanisms of orthostatic intolerance and their clinical significance.
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PMID:Orthostatic intolerance: potential pathophysiology and therapy. 1561 27

Cyclic vomiting syndrome, which is characterized by severe discrete episodes of nausea, vomiting, and lethargy, is a fairly common, disabling, predominately childhood condition. Approximately 25% of cases have coexisting neuromuscular disease manifestations (cyclic vomiting syndrome plus). To determine whether patients with cyclic vomiting syndrome and neuromuscular disease represent a distinct subentity within cyclic vomiting syndrome, a clinical interview was conducted regarding 80 randomly ascertained sufferers of cyclic vomiting syndrome from a disease association database. Cyclic vomiting syndrome plus and "cyclic vomiting syndrome minus," herein defined as the presence of at least two and zero neuromuscular disease manifestations, were present in 23 and 44 subjects, respectively. Neuromuscular disease manifestations, including cognitive disorders, skeletal myopathy, cranial nerve dysfunction, and seizure disorders, were found to statistically cluster together among the same subjects. In addition, subjects with cyclic vomiting syndrome with neuromuscular disease had an earlier age at onset for vomiting episodes and a three- to eightfold statistically increased prevalence for certain dysautonomia-related (migraine, chronic fatigue, neurovascular dystrophy) and constitutional (growth retardation and birth defects) disorders. However, subjects with cyclic vomiting syndrome with and without neuromuscular disease were equally likely to have a sibling affected with neuromuscular disease manifestations. We conclude that cyclic vomiting syndrome plus, although likely not genetically distinct from cyclic vomiting syndrome minus, represents a distinct phenotypic entity that predicts an earlier onset of disease and increased comorbidity with a distinct list of medical conditions, possibly owing to a higher degree of mitochondrial dysfunction.
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PMID:Cyclic vomiting syndrome plus. 1690 17

Some overlap between features of fibromyalgia and systemic lupus erythematous (SLE) is well-recognized. Our objective is to describe eight patients with an original diagnosis of SLE, in whom, after re-evaluation, the multi-system symptoms could be explained on the basis of the dysautonomia that occurs in fibromyalgia.Seven of the eight patients were females. Their mean age was 31 years. All of them fulfilled the American College of Rheumatology criteria for fibromyalgia. Their lupus-like features that could later be explained by dysautonomia were the following: diffuse arthralgias with subjective feeling of swelling, malar erythema, syncopal episodes, profound fatigue, and distal vasospastic changes. Six patients had low titer ANA. None of the patients had signs of organic damage. Autonomic dysfunction was demonstrated by means of circadian studies of heart rate variability (6 patients) and/or tilt table testing (3 patients). We conclude that autonomic dysfunction may be an explanation for the lupus-like symptoms present in some patients with FM.
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PMID:The dysautonomia of fibromyalgia may simulate lupus. 1907 25

Fibromyalgia (FM) is a common, complex, and difficult to treat chronic widespread pain disorder, which usually requires a multidisciplinary approach using both pharmacological and non-pharmacological (education and exercise) interventions. It is a condition of heightened generalized sensitization to sensory input presenting as a complex of symptoms including pain, sleep dysfunction, and fatigue, where the pathophysiology could include dysfunction of the central nervous system pain modulatory systems, dysfunction of the neuroendocrine system, and dysautonomia. A cyclic model of the pathophysiological processes is compatible with the interrelationship of primary symptoms and the array of postulated triggers associated with FM. Many of the molecular targets of current and emerging drugs used to treat FM have been focused to the management of discrete symptoms rather than the condition. Recently, drugs (eg, pregabalin, duloxetine, milnacipran, sodium oxybate) have been identified that demonstrate a multidimensional efficacy in this condition. Although the complexity of FM suggests that monotherapy, non-pharmacological or pharmacological, will not adequately address the condition, the outcomes from recent clinical trials are providing important clues for treatment guidelines, improved diagnosis, and condition-focused therapies.
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PMID:Treatment options and patient perspectives in the management of fibromyalgia: future trends. 1933 51


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