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

The diagnosis of adrenal hypofunction is suggested by clinical features and confirmed by biochemical testing. The characteristic features of acute primary adrenal insufficiency include orthostatic hypotension, fever, and hypoglycemia. By contrast, patients with chronic primary adrenal insufficiency have a longer history of malaise, as well as fatigue, anorexia, diarrhea, weight loss, joint and back pain, and darkening of the skin. While the clinical presentation of secondary adrenal insufficiency is similar to that of primary adrenal insufficiency, there is no hyperpigmentation, and hypotension and orthostasis are less pronounced. As a result, patients often present with vague, non-specific symptoms and the diagnosis may not be entertained. There is considerable debate regarding the best dynamic test for the diagnosis of adrenal hypofunction. Optimally, a screening test would be economic, convenient and safe. It would have high sensitivity and specificity based on consensus criteria for interpretation. Unfortunately, to date no test meets all of these criteria. Measurement of basal cortisol is an inexpensive and convenient screening test that can include (< 3 microg/dl; 83 nmol/l) or exclude (> 19 microg/dl; 524 nmol/l) adrenal insufficiency. However, most patients will have intermediate values and will require dynamic testing. This review discusses the use of metyrapone, insulin, CRH and synthetic ACTH 1-24 as provocative agents for cortisol secretion. Although the insulin and metyrapone stimulation tests have the advantage of testing the entire hypothalamic-pituitary-adrenal axis, they are cumbersome and carry more risk than the other tests. The 250 microg ACTH test works well to identify primary adrenal hypofunction, but can only detect secondary adrenal hypofunction when there is sufficient time for the glands to atrophy because of reduced endogenous ACTH stimulation. The 1 microg ACTH test has been advocated in the setting of possible secondary adrenal insufficiency, but its widespread use has been mitigated by the lack of a commercial preparation of this small dose and controversy regarding diagnostic criteria. Ultimately, the choice of test should be individualized for each patient, with knowledge of the available reference assays and the vagaries of each test.
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PMID:Dynamic evaluation of adrenal hypofunction. 1460 69

An end-stage renal disease patient on long-term peritoneal dialysis was admitted with dizziness, fatigue, hypoglycemia, and hypotension. The hypotension resolved with intravenous normal saline, but the hypoglycemia persisted for 3 days despite an intravenous dextrose drip and discontinuation of gabapentin. The patient became normoglycemic on the fourth day of admission. None of the known causes for the hypoglycemia were identified except gabapentin, the dose of which was recently doubled 1 month before admission. Insulin and C-peptide levels were high during the hypoglycemic episode and returned to normal after discontinuation of gabapentin. The patient remains off gabapentin and has had no further episodes of hypoglycemia. To our knowledge, this is the first case of hypoglycemia induced by gabapentin.
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PMID:Gabapentin-induced hypoglycemia in a long-term peritoneal dialysis patient. 1465 24

Despite pituitary hormone replacement, patients with craniopharyngioma often complain of fatigue. They may have deficient control of catecholamine secretion caused by hypothalamic lesion. Another hypothesis is a functional defect in catecholamine production through either glucocorticoid deficiency because high intraadrenal glucocorticoid concentration is necessary for epinephrine synthesis or unrecognized hypoglycemia, which can intrinsically alter epinephrine secretion. We measured catecholamine response to insulin-induced hypoglycemia and orthostasis, and 24-h urinary catecholamine excretion, in 16 children with craniopharyngioma (patients) and 27 sex- and age-matched short children. We also studied the influence of a 4-fold increase in the usual daily dose of hydrocortisone on catecholamine excretion (50 vs. 12 mg/m(2) of body surface area) in the glucocorticoid-deficient patients. Last, we compared 24-h continuous sc glucose in patients and 10 sex- and age-matched healthy children. The results are expressed as medians (25th, 75th). For a similar blood glucose nadir after insulin administration, peak plasma epinephrine in response to hypoglycemia was lower in patients vs. controls [420 (120, 715) vs. 730 (460, 1200) ng/liter, P < 0.01], whereas peak plasma norepinephrine was higher [390 (280, 550) vs. 270 (180, 280) ng/liter, P < 0.05]. Catecholamine response to orthostasis did not differ between groups. Urinary epinephrine was significantly lower in patients (P < 0.001), whereas urinary norepinephrine was similar. The extent of epinephrine deficiency correlated with neither tumor size nor hypothalamic involvement. A 4-fold higher hydrocortisone dose did not correct the defective epinephrine excretion in the glucocorticoid-deficient patients. Last, the 24-h sc glucose values were similar between patients and controls. In conclusion, children with craniopharyngioma have a defect in epinephrine but not norepinephrine production. There is no proof of a univocal origin, either organic or functional. Whether abnormal catecholamine secretion alters glucose level during fasting or acute illness, or hampers adaptation to exercise, requires further studies.
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PMID:Defect in epinephrine production in children with craniopharyngioma: functional or organic origin? 1467 Nov 98

Chronic fatigue syndrome (CFS) is defined as constellation of the prolonged fatigue and several somatic symptoms, in the absence of organic or severe psychiatric disease. However, this is an operational definition and conclusive biomedical explanation remains elusive. Similarities between the signs and symptoms of CFS and adrenal insufficiency prompted the research of the hypothalamo-pituitary-adrenal axis (HPA) derangement in the pathogenesis of the CFS. Early studies showed mild glucocorticoid deficiency, probably of central origin that was compensated by enhanced adrenal sensitivity to ACTH. Further studies showed reduced ACTH response to vasopressin infusion. The response to CRH was either blunted or unchanged. Cortisol response to insulin induced hypoglycaemia was same as in the control subjects while ACTH response was reported to be same or enhanced. However, results of direct stimulation of the adrenal cortex using ACTH were conflicting. Cortisol and DHEA responses were found to be the same or reduced compared to control subjects. Scott et al found that maximal cortisol increment from baseline is significantly lower in CFS subjects. The same group also found small adrenal glands in some CFS subjects. These varied and inconsistent results could be explained by the heterogeneous study population due to multifactorial causes of the disease and by methodological differences. The aim of our study was to assess cortisol response to low dose (1 microgram) ACTH using previously validated methodology. We compared cortisol response in the CFS subjects with the response in control and in subjects with suppressed HPA axis due to prolonged corticosteroid use. Cortisol responses were analysed in three subject groups: control (C), secondary adrenal insufficiency (AI), and in CFS. The C group consisted of 39 subjects, AI group of 22, and CFS group of nine subjects. Subject data are presented in table 1. Low dose ACTH test was started at 0800 h with the i.v. injection of 1 microgram ACTH (Galenika, Belgrade, Serbia). Blood samples for cortisol determination were taken from the i.v. cannula at 0, 15, 30, and 60 min. Data are presented as mean +/- standard error (SE). Statistical analysis was done using ANOVA with the Games-Howell post-hoc test to determine group differences. ACTH dose per kg or per square meter of body surface was not different between the groups. Baseline cortisol was not different between the groups. However, cortisol concentrations after 15 and 30 minutes were significantly higher in the C group than in the AI group. Cortisol concentration in the CFS group was not significantly different from any other group (Graph 1). Cortisol increment at 15 and 30 minutes from basal value was significantly higher in C group than in other two groups. However, there was no significant difference in cortisol increment between the AI and CFS groups at any time of the test. On the contrary, maximal cortisol increment was not different between CFS and other two groups, although it was significantly higher in C group than in the AI group. Maximal cortisol response to the ACTH stimulation and area under the cortisol response curve was significantly larger in C group compared to AI group, but there was no difference between CFS and other two groups. Several previous studies assessed cortisol response to ACTH stimulation. Hudson and Cleare analysed cortisol response to 1 microgram ACTH in CFS and control subjects. They compared maximum cortisol attained during the test, maximum cortisol increment, and area under the cortisol response curve. There was no difference between the groups in any of the analysed parameters. However, authors commented that responses were generally low. On the contrary Scott et al found that cortisol increment at 30 min is significantly lower in the CFS than in the control group. Taking into account our data it seems that the differences found in previous studies papers are caused by the methodological differences. We have shown that cortisol increment at 15 and 30 min is significantly lower in CFS group than in C group. Nevertheless, maximum cortisol attained during the test, maximum cortisol increment, and area under the cortisol response curve were not different between the C and CFS groups. This is in agreement with our previous findings that cortisol increment at 15 minutes has the best diagnostic value of all parameters obtained during of low dose ACTH test. However, there was no difference between CFS and AI group in any of the parameters, although AI group had significantly lower cortisol concentrations at 15 and 30 minutes, maximal cortisol response, area under the cortisol curve, maximal cortisol increment, and maximal cortisol change velocity than C group. Consequently, reduced adrenal responsiveness to ACTH exists in CFS. In conclusion, we find that regarding the adrenal response to ACTH stimulation CFS subjects present heterogeneous group. In some subjects cortisol response is preserved, while in the others it is similar to one found in secondary adrenal insufficiency.
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PMID:[Disorder of adrenal gland function in chronic fatigue syndrome]. 1505 15

Chronic renal failure (CRF) is associated with oxidative stress that promotes production of reactive oxygen species. L-Carnitine is a cofactor required for transport of long-chain fatty acids into the mitochondrial matrix. Recent research has shown that some clinical conditions (i.e., anorexia, chronic fatigue, coronary heart disease, diphtheria, hypoglycemia, and male infertility) benefit from exogenous supplementation of L-carnitine. The aim of this study was to examine the role of L-carnitine in protecting the aorta, heart, corpus cavernosum, and kidney tissues against oxidative damage in a rat model of CRF. Male Wistar albino rats were randomly assigned to either the CRF group or the sham-operated control group, which had received saline or L-carnitine (500 mg/kg, i.p.) for 4 weeks. CRF was evaluated by BUN and serum creatinine measurements. Aorta and corporeal tissues were used for contractility studies or stored along with heart and kidney tissues for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels. Plasma MDA, GSH levels and erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were also studied. In the CRF group, the contraction and the relaxation of aorta and corpus cavernosum samples decreased significantly compared with controls and were partially reversed by L-carnitine treatment. In the CRF group, there were significant increases in tissue MDA with marked reductions in GSH levels in all tissues and plasma compared with controls. In the plasma SOD, CAT and GSH-Px activities were also reduced. All these effects were reversed by L-carnitine as well. The increase in MDA level and the concomitant decrease in GSH level of tissues and plasma and also suppression of the antioxidant enzyme activities in plasma demonstrate that oxidative mechanisms are involved in CRF-induced tissue damage. L-carnitine, possibly via its free radical scavenging and antioxidant properties, ameliorates oxidative organ injury and CRF-induced dysfunction of the aorta and corpus cavernosum. These results suggest that L-carnitine supplementation may have some benefit in CRF patients.
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PMID:L-carnitine ameliorates oxidative damage due to chronic renal failure in rats. 1507 58

The exacerbation of symptoms after exercise differentiates Chronic fatigue syndrome (CFS) from several other fatigue-associated disorders. Research data point to an abnormal response to exercise in patients with CFS compared to healthy sedentary controls, and to an increasing amount of evidence pointing to severe intracellular immune deregulations in CFS patients. This manuscript explores the hypothetical interactions between these two separately reported observations. First, it is explained that the deregulation of the 2-5A synthetase/RNase L pathway may be related to a channelopathy, capable of initiating both intracellular hypomagnesaemia in skeletal muscles and transient hypoglycemia. This might explain muscle weakness and the reduction of maximal oxygen uptake, as typically seen in CFS patients. Second, the activation of the protein kinase R enzyme, a characteristic feature in atleast subsets of CFS patients, might account for the observed excessive nitric oxide (NO) production in patients with CFS. Elevated NO is known to induce vasidilation, which may limit CFS patients to increase blood flow during exercise, and may even cause and enhanced postexercise hypotension. Finally, it is explored how several types of infections, frequently identified in CFS patients, fit into these hypothetical pathophysiological interactions.
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PMID:Chronic fatigue syndrome: intracellular immune deregulations as a possible etiology for abnormal exercise response. 1508 2

This review addresses cerebral metabolic and neurohumoral alterations during prolonged exercise in humans with special focus on associations with fatigue. Global energy turnover in the brain is unaltered by the transition from rest to moderately intense exercise, apparently because exercise-induced activation of some brain regions including cortical motor areas is compensated for by reduced activity in other regions of the brain. However, strenuous exercise is associated with cerebral metabolic and neurohumoral alterations that may relate to central fatigue. Fatigue should be acknowledged as a complex phenomenon influenced by both peripheral and central factors. However, failure to drive the motorneurons adequately as a consequence of neurophysiological alterations seems to play a dominant role under some circumstances. During exercise with hyperthermia excessive accumulation of heat in the brain due to impeded heat removal by the cerebral circulation may elevate the brain temperature to >40 degrees C and impair the ability to sustain maximal motor activation. Also, when prolonged exercise results in hypoglycaemia, perceived exertion increases at the same time as the cerebral glucose uptake becomes low, and centrally mediated fatigue appears to arise as the cerebral energy turnover becomes restricted by the availability of substrates for the brain. Changes in serotonergic activity, inhibitory feed-back from the exercising muscles, elevated ammonia levels, and alterations in regional dopaminergic activity may also contribute to the impaired voluntary activation of the motorneurons after prolonged and strenuous exercise. Furthermore, central fatigue may involve depletion of cerebral glycogen stores, as signified by the observation that following exhaustive exercise the cerebral glucose uptake increases out of proportion to that of oxygen. In summary, prolonged exercise may induce homeostatic disturbances within the central nervous system (CNS) that subsequently attenuates motor activation. Therefore, strenuous exercise is a challenge not only to the cardiorespiratory and locomotive systems but also to the brain.
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PMID:Cerebral perturbations provoked by prolonged exercise. 1514 84

Mitochondrial fatty acid beta-oxidation is an important energy resource for many mammal tissues. Acyl-CoA dehydrogenases (ACADs) are a family of flavoproteins that are involved in the beta-oxidation of the fatty acyl-CoA derivatives. Deficiency of these ACADs can cause metabolic disorders including muscle fatigue, hypoglycaemia, hepatic lipidosis and so on. By large scale sequencing, we identified a cDNA sequence of 3960 base pairs with a typical acyl-CoA dehydrogenase function domain. RT-PCR result shows that it is widely expressed in human tissues, especially high in liver, kidney, pancreas and spleen. It is hypothesized that this is a novel member of ACADs family.
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PMID:Cloning and characterization of a human cDNA ACAD10 mapped to chromosome 12q24.1. 1556 Mar 74

Beta-blockers utilized in the Type 2 diabetic patient result in an even greater decrease in cardiac events than in the nondiabetic patient. Unfortunately, first-and second-generation beta-blockers are associated with the worsening of insulin resistance, deterioration of glycemic control, peripheral vasoconstriction, potentially worsening peripheral vascular disease, and more frequent and severe hypoglycemia. The third-generation beta-blockers have unique properties, including alpha1-blockade, and have been shown to lower insulin resistance, improve glycemic control, and vasodilate resistance arterioles. The Glycemic Effects in Diabetes Mellitus: Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial has been designed to compare a third-generation (carvedilol) with a second-generation beta-blocker (metoprolol) in a cohort of participants with hypertension and Type 2 diabetes. The primary outcome measure of the study is change in the HbA1c. The study is powered to detect a difference in HbA1c of 0.3 units (%) between the groups. Secondary endpoints include changes in insulin resistance, fasting glucose, and the lipid profile. Differences in the side-effect profile (cold extremities, fatigue, impotence, and hypoglycemia) will also be assessed. The GEMINI trial, therefore, is the first large randomized trial to assess whether utilizing a third-generation beta-blocker yields a favorable metabolic profile in the patient with Type 2 diabetes and hypertension.
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PMID:The rationale and design of the Glycemic Effects in Diabetes Mellitus Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial. 1574 36

We report a case of a 37-yr-old man with a 11-yr history of Crohn's disease (CD), who presented with mucous diarrheas of 1-week duration and a 3-month history of anorexia, increasing fatigue and weight loss of 7 kg. The patient was treated with sulfasalazine 3 g/day until 2 weeks prior to the present admission, when he reduced the dose to half as he considered the drug responsible for his symptoms. Despite aggressive iv rehydration and resolution of diarrheas with an increase in sulfasalazine dose, the patient remained hemodynamically unstable, while laboratory results showed anemia, hypoglycemia, hypertransaminasemia and hyponatremia with marked natriuresis. Thyroid function tests were consistent with primary hypothyroidism, without evidence of autoimmunity. Further laboratory investigation revealed a low basal cortisol and undetectable ACTH with preserved secretory responses of the other trophic pituitary hormones, establishing the diagnosis of isolated ACTH deficiency. Hydrocortisone replacement treatment induced a clinical and laboratory improvement. The autoimmune basis of isolated ACTH deficiency is discussed in association with the presumed contribution of immunologic reactions in the pathogenesis of CD. However more evidence is needed before isolated ACTH deficiency is added to the list of extraintestinal manifestations of CD.
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PMID:Isolated ACTH deficiency associated with Crohn's disease. 1576 46


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