Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dyspnea is the medical term for the patient's or subject's complaint of shortness of breath. It encompasses the respiratory discomfort experienced in many different diease states as well as the shortness of breath felt by a normal subject during or after strenuous exercise. Several parameters which have been shown to correlate with the onset or severity of dyspnea are described, including reduced vital capacity, the ratio of minute ventilation to vital capacity, reduced breathing reserve, the work of breathing, and the oxygen cost of breathing. Attempts at quantitation of dyspnea have usually consisted of measuring physiological parameters associated with the sensation, such as the "dyspneic index". The direct measurement of respiratory sensations using modern psycho-physical methods is at an early stage of development. Since the observation that the existence of dyspnea is often unrelated to any disturbance of arterial blood gas composition, it has been generally held that the mechanism of dyspnea is primarily neurophysiological. The neural pathways may conceptually be divided into those which transmit the "dyspnea message" from the respiratory apparatus to integrating centers in the brain, and those concerned with subsequently bringing the sensation to the level of consciousness. It seems likely that there is no single sensing mechanism and neural pathway which will be able to explain dyspnea in the diverse populations of patients and subjects who experience unpleasant respiratory sensations. Three theories concerning mechanisms of dyspnea are briefly described: "length-tension inappropriateness", vagal afferent activity especially from the J-receptors, and the recent concept of diaphragmatic fatigue. Some specific characteristics of the shortness of breath experienced in certain disease states are described, including chronic bronchitis and emphysema, bronchial asthma, pulmonary fibrosis and congestive heart disease.
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PMID:Dyspnea. 50 81

Although balanced positive pressure breathing increases protection by G suits and reduces fatigue during sustained high Gz exposures, it does not prevent dependent pulmonary right-to-left shunts (arterial hypoxemia) and potentially dangerous distention of nondependent alveoli. An incident of acute incapacitating mediastinal emphysema in a healthy young man during a sustained exposure to 5.5 Gx documents this possibility. This, plus neurogenic bradycardia during sustained high Gz exposures without pressure breathing, suggests that testing of full counterpressure to neck level suits at sustained > 9 Gz exposures may be hazardous. Fully instrumented studies of animal surrogates with comparable thoracic dimensions are indicated.
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PMID:Potential hazards of high anti-Gz suit protection. 144 54

This paper reported the methods and results of maximum transdiaphragmatic pressure (Pdi max) and diaphragm electromyography (EMGdi) in 16 patients with obstructive emphysema. A correlation analysis showed that Pdimax is negatively related to PaCO2, FRC%, and positively to VC, IC, FVC and MVV closely. Diaphragmatic fatigue was induced by inspiratory resistive loaded breathing with the parameters of 60% Pdimax and 5 minutes lasting. The influential effects and clinical value of diaphragm examination were discussed.
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PMID:[Examination of maximum transdiaphragmatic pressure, diaphragm electromyography in patients with obstructive emphysema]. 147 88

In adult male hamsters the influence of emphysema (EMP) on the in vitro contractile and fatigue properties and the histochemical, morphometric, and metabolic properties of muscle fibers in the costal diaphragm was determined 6 mo after the administration of either elastase or saline (controls, CTL). Isometric contractile properties were determined in vitro using supramaximal direct muscle stimulation. Optimal fiber length for force generation was significantly shorter in the EMP than in the CTL diaphragm. Maximum specific force (i.e., force per unit area) was 25% lower than CTL. Fatigue resistance was significantly improved in the EMP diaphragm compared with CTL. Diaphragm muscle fibers were classified as type I or II on the basis of histochemical staining for myofibrillar adenosinetriphosphatase after alkaline preincubation. The proportions of type I and II fibers were similar between the two groups. Cross-sectional areas of type II fibers were 30% larger in EMP than in CTL diaphragms. Succinate dehydrogenase activities of both type I and II fibers were higher in EMP than in CTL diaphragms. The number of capillaries surrounding both type I and II fibers increased with EMP, but in proportion to the hypertrophy of these fibers. Thus, capillary density (number of capillaries per fiber cross-sectional area) remained unchanged. We postulate that these contractile, morphometric, and metabolic adaptations reflect an increased activation of the diaphragm in response to the loads imposed by EMP.
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PMID:Adaptations of the diaphragm in emphysema. 156 89

We studied the changes of histochemical properties of diaphragm in guinea pigs with elastase-induced emphysema. Using myofibrillar ATPase staining, three types of diaphragmatic muscle fibers were classified as slow-twitch, oxidative (SO), fast-twitch, oxidative, glycolytic (FOG), and fast-twitch, glycolytic (FG). Capillaries adjacent to individual fibers were also demonstrated by ATPase reaction. After 24 weeks of tracheal instillation of elastase, both the size and number of SO and FOG fibers were increased, thereby indicating the increase in relative areas occupied by these oxidative fibers in the diaphragm (p less than 0.01 in each case). Moreover, these changes were accompanied by the increased capillary density (p less than 0.01). These results suggest that chronic respiratory load with emphysema may establish the diaphragm more resistant to fatigue by increasing oxidative capacity of the diaphragmatic muscle fibers.
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PMID:Effects of elastase-induced emphysema on histochemical properties of guinea pig diaphragm. 246 17

Chest negative pressure ventilation (CNPV) and intermittent positive pressure ventilation (IPPV) through a nose mask were used for ventilatory support of 4 patients with chronic respiratory failure due to old tuberculosis (2 patients), chronic pulmonary emphysema, and kyphoscoliosis (VC, 0.91 +/- 0.16 L; %VC 31.2 +/- 3.2; FEV1.0, 0.62 +/- 0.19 L). These ventilatory supports were used for relief of chronic arterial CO2 retention, weaning from the mechanical ventilation, therapy for the acute exacerbation on the chronic respiratory failure, and the relief of the respiratory muscle fatigue. After CNPV and IPPV through a nose mask, PaCO2 showed a significant fall from 75.7 +/- 14.8 Torr to 60.2 +/- 12.3 Torr (p less than 0.01). All patients showed improvement of clinical symptoms. Two patients have continued CNPV at home on a regular basis. We conclude that CNPV and IPPV through a nose mask significantly improve hypoventilation and quality of life in some patients with chronic respiratory failure.
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PMID:[Noninvasive ventilatory support on chronic respiratory failure with hypoventilation]. 262 Jan 35

This study compared recalled physical and emotional sensations during episodes of acute dyspnea across pulmonary disease groups. The convenience sample consisted of 68 subjects with emphysema-bronchitis, asthma, vascular, and restrictive disease. Temporal patterns of physical and emotional sensations before and during episodes of dyspnea were identified. The frequency of sensations was remarkably similar across disease categories with few significant differences identified. Rather than the disease category, the frequency, intensity, and periodicity of the symptom of dyspnea had the greatest effect on the quality and frequency of sensations reported. The intensity of usual dyspnea reported on a visual analog scale varied significantly among groups, p = .026, with asthmatics having the lowest mean score and vascular subjects the highest. Females reported significantly greater usual dyspnea than males, p = .005. The variables of pulmonary disease group, gender, fatigue, and total network of social support were significantly related to usual dyspnea, and pulmonary group, gender, and attendance at Better Breathers classes were significantly related to worst dyspnea.
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PMID:The sensations of pulmonary dyspnea. 363 51

Cefotaxime (CTX) was used for 129 cases in respiratory tract and other infections; 57 cases of pneumonia, 20 cases of bronchopneumonia, 20 cases of acute bronchitis, 14 cases of chronic bronchitis, 7 cases of acute exacerbation of bronchiectasia or pulmonary emphysema, 4 cases of suppurative diseases of the lung, 1 case of pyothorax, 1 case of retropharyngeal abscess, 3 cases of pleurisy and 1 case of urinary tract infection. (A case was excepted on clinical evaluation.) CTX was administered by intravenous injection or drip infusion at a daily dose ranging from 0.5 to 8 g, for a term of 2 to 61 days. The total dose patients received ranged from 3 to 226 g. The results obtained were as follows. Clinical effects; excellent in 45 cases, good in 63 cases, fair in 9 cases, poor in 7 cases and unevaluable in 4 cases. The efficacy rate was 87.1% (108/124). Bacteriological effects; eliminated in 30 cases, decreased in 8 cases, unchanged in 2 cases and replaced in 1 case. The elimination rate was 75.6% (31/41). Side effects and abnormal laboratory findings; general itching, fatigue in lower extremities and albuminuria in 1 case each, and anemia in 2 cases. Increased number of eosinophiles and elevated GOT in 1 case each, elevated GOT and GPT in 3 cases and elevated GOT, GPT and A1-P in 2 cases. These symptoms or abnormal laboratory findings disappeared after the discontinuation or termination of CTX therapy. In view of the above, CTX may be considered to be a clinically useful antibiotic against respiratory tract infections.
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PMID:[Clinical evaluation of cefotaxime in internal medicine]. 631 10

Subjective symptoms and experiences were explored within a group of 146 severe, chronic bronchitis and emphysema patients. Eighty-nine symptoms and experiences, derived from initial interviews with 29 patients, were rated according to the frequency of occurrence during breathing difficulties. Key cluster analyses were used to derive a Bronchitis-Emphysema Symptom Checklist (BESC) measuring 11 symptom categories: Helplessness-Hopelessness, Decathexis, Fatigue, Poor Memory, Peripheral-Sensory Complaints, Dyspnea, Congestion, Sleep Difficulties, Irritability, Anxiety, and Alienation. The BESC symptom categories are highly reliable and the relationships among categories are stable across two subgroups of patients. The BESC provides one way to describe how patients cope with and experience chronic bronchitis and emphysema.
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PMID:Multidimensional analysis of the symptoms of chronic bronchitis and emphysema. 666 2

A heterogeneous group of 146 patients with chronic bronchitis and emphysema were asked to rate the frequency with which 89 symptoms and experiences occurred during their breathing difficulties. Normative values and the reported frequency of occurrence for the 11 symptom categories are presented. As expected, symptoms of dyspnea were the most frequently reported during breathing difficulties. In decreasing order, symptoms of dyspnea were followed by symptoms of fatigue, sleep disturbance, congestion, irritability, anxiety, decathexis, helplessness-hopelessness, poor memory, alienation. Separation of the patients into subgroups revealed that women reported more anxiety and helplessness-hopelessness than men. Younger patients reported more irritability and anxiety than older patients. Patients with mixed disease reported more dyspnea than those with chronic bronchitis or emphysema, although patients with emphysema reported more loss of interest in life than patients with chronic bronchitis. Self-ratings of functional incapacitation were clearly related to the symptom reports. Relationships among the symptom categories were discussed, as was the potential usefulness of symptom patterns in exploring coping styles in respiratory disease.
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PMID:Symptoms and experiences in chronic bronchitis and emphysema. 683 16


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