Category: Pathophysiology

Multiple mycoplasmal infections detected in blood of patients with chronic fatigue syndrome and/or fibromyalgia syndrome

Abstract:

The aim of this study was to investigate the presence of different mycoplasmal species in blood samples from patients with chronic fatigue syndrome and/or fibromyalgia syndrome. Previously, more than 60% of patients with chronic fatigue syndrome/fibromyalgia syndrome were found to have mycoplasmal blood infections, such as Mycoplasma fermentans infection.

In this study, patients with chronic fatigue syndrome/fibromyalgia syndrome were examined for multiple mycoplasmal infections in their blood. A total of 91 patients diagnosed with chronic fatigue syndrome/fibromyalgia syndrome and with a positive test for any mycoplasmal infection were investigated for the presence of Mycoplasma fermentans, Mycoplasma pneumoniae, Mycoplasma hominis and Mycoplasma penetrans in blood using forensic polymerase chain reaction.

Among these mycoplasma-positive patients, infections were detected with Mycoplasma pneumoniae (54/91), Mycoplasma fermentans (44/91), Mycoplasma hominis (28/91) and Mycoplasma penetrans (18/91). Multiple mycoplasmal infections were found in 48 of 91 patients, with double infections being detected in 30.8% and triple infections in 22%, but only when one of the species was Mycoplasma pneumoniae or Mycoplasma fermentans. Patients infected with more than one mycoplasmal species generally had a longer history of illness, suggesting that they may have contracted additional mycoplasmal infections with time.

 

Source: Nasralla M, Haier J, Nicolson GL. Multiple mycoplasmal infections detected in blood of patients with chronic fatigue syndrome and/or fibromyalgia syndrome. Eur J Clin Microbiol Infect Dis. 1999 Dec;18(12):859-65. http://www.ncbi.nlm.nih.gov/pubmed/10691196

 

Disturbed neuroendocrine-immune interactions in chronic fatigue syndrome

Abstract:

The present study was designed to investigate the interaction between neuroendocrine mediators and the immune system in chronic fatigue syndrome (CFS). We examined the sensitivity of the immune system to the glucocorticoid agonist dexamethasone and the beta2-adrenergic agonist terbutaline in 15 adolescent girls with CFS and 14 age- and sex-matched controls.

Dexamethasone inhibits T-cell proliferation in healthy controls and in CFS patients. However, the maximal effect of dexamethasone on T-cell proliferation is significantly reduced in CFS patients as compared with controls. The beta2-adrenergic receptor agonist terbutaline inhibits tumor necrosis factor-alpha production and enhances interleukin-10 production by monocytes. Our data demonstrate that the capacity of a beta2-adrenergic agonist to regulate the production of these two cytokines is also reduced in CFS patients.

We did not observe differences in baseline or CRH-induced cortisol and ACTH between CFS patients and controls. Baseline noradrenaline was similar in CFS and controls, whereas baseline adrenaline levels were significantly higher in CFS patients. We conclude that CFS is accompanied by a relative resistance of the immune system to regulation by the neuroendocrine system. Based on these data, we suggest CFS should be viewed as a disease of deficient neuroendocrine-immune communication.

 

Source: Kavelaars A, Kuis W, Knook L, Sinnema G, Heijnen CJ. Disturbed neuroendocrine-immune interactions in chronic fatigue syndrome. J Clin Endocrinol Metab. 2000 Feb;85(2):692-6. http://www.ncbi.nlm.nih.gov/pubmed/10690878

 

Competition for glutathione precursors between the immune system and the skeletal muscle: pathogenesis ofchronic fatigue syndrome

Abstract:

The chronic fatigue syndrome (CFS) is typically associated or follows a recognized or presumed infection. Abnormalities of both humoral and cellular immunity have been demonstrated in a substantial proportion of patients with CFS. The most consistent findings are of impaired lymphocyte responses to mitogen.

As an antioxidant, glutathione (GSH) is essential for allowing the lymphocyte to express its full potential without being hampered by oxiradical accumulation. Hence, protracted challenge of the immunocytes may lead to cellular GSH depletion. Because GSH is also essential to aerobic muscular contraction, an undesirable competition for GSH precursors between the immune and muscular systems may develop.

It is conceivable that the priority of the immune system for the survival of the host has drawn to this vital area the ever-diminishing GSH precursors, thus depriving the skeletal muscle of adequate GSH precursors to sustain a normal aerobic metabolism resulting in fatigue and eventually myalgia.

 

Source: Bounous G, Molson J. Competition for glutathione precursors between the immune system and the skeletal muscle: pathogenesis ofchronic fatigue syndrome. Med Hypotheses. 1999 Oct;53(4):347-9. http://www.ncbi.nlm.nih.gov/pubmed/10608272

 

Brain MRI abnormalities exist in a subset of patients with chronic fatigue syndrome

Abstract:

Presence of MRI brain abnormalities in patients with Chronic Fatigue Syndrome (CFS) was determined and the profile of MRI abnormalities was compared between 39 CFS patients, 18 with (CFS-Psych) and 21 without (CFS-No Psych) a DSM-III-R Axis I psychiatric diagnosis since illness onset, and 19 healthy, sedentary controls (HC).

Two neuroradiologists, blind to group membership, separately read the MR films using a detailed protocol for rating and categorizing abnormal signal changes. When findings were incongruent, the two neuroradiologists met to try to reach consensus, otherwise a third neuroradiologist evaluated the MR images and served as a tie-breaker.

The CFS-No Psych group showed a significantly larger number of brain abnormalities on T2 weighted images than the CFS-Psych and HC groups. Cerebral changes in the CFS-No Psych group consisted mostly of small, punctate, subcortical white matter hyperintensities, found predominantly in the frontal lobes. No significant difference was found when both CFS groups were combined and compared to the HC group.

The use of stratification techniques is an important strategy in understanding the pathophysiology of CFS. This frontal lobe pathology could explain the more severe cognitive impairment previously reported in this subset of CFS patients.

Comment in: Brain MRI abnormalities exist in chronic fatigue syndrome. [J Neurol Sci. 1999]

 

Source: Lange G, DeLuca J, Maldjian JA, Lee H, Tiersky LA, Natelson BH. Brain MRI abnormalities exist in a subset of patients with chronic fatigue syndrome. J Neurol Sci. 1999 Dec 1;171(1):3-7. http://www.ncbi.nlm.nih.gov/pubmed/10567042

 

The Chronic Fatigue Twin Registry: method of construction, composition, and zygosity assignment

Abstract:

Chronic fatigue syndrome (CFS) and the symptom of chronic fatigue are conditions of unknown etiology. The Centers for Disease Control and Prevention (CDC) define CFS as an illness characterized by > or = 6 months of disabling fatigue associated with muscle pain, pharyngitis, and alterations in mood, sleep and neurocognition. We constructed a registry of twins with chronic fatigue to facilitate research on the impact of illness, the associated medical and psychosocial factors, and the heterogeneous proposed mechanisms for these conditions.

We have recruited 204 twin pairs in which one or both members reported persistent fatigue through patient support group newsletters (60%), clinicians/researchers familiar with CFS (12%), notices placed on electronic bulletin boards for CFS (11%), twin organizations and researchers (6%), relatives and friends (3%) and other sources (8%). Complete data are available for 177 pairs (87%). Twins completed an extensive questionnaire booklet that included measures of physical and mental health, functional status, and psychosocial factors; a structured psychiatric interview was also conducted by telephone.

Twins were classified using three increasingly more stringent diagnostic criteria for chronic fatigue: 1) > or = 6 months of fatigue (115 discordant and 61 concordant pairs); 2) chronic fatigue with additional symptoms and application of the medial exclusions of the CDC CFS case definition as obtained by self-report (92 discordant and 41 concordant pairs) and; 3) chronic fatigue with additional symptoms unexplained by self-reported medical conditions and psychiatric diagnoses as determined by the structured interview (69 discordant pairs and 25 concordant pairs).

Despite the limitations of a volunteer registry, the Chronic Fatigue Twin Registry promises to be an important resource for research on CFS and chronic fatigue.

 

Source: Buchwald D, Herrell R, Ashton S, Belcourt M, Schmaling K, Goldberg J. The Chronic Fatigue Twin Registry: method of construction, composition, and zygosity assignment. Twin Res. 1999 Sep;2(3):203-11. http://www.ncbi.nlm.nih.gov/pubmed/10555131

 

Small adrenal glands in chronic fatigue syndrome: a preliminary computer tomography study

Abstract:

No inclusive or satisfactory biomedical explanation for chronic fatigue syndrome (CFS) has as yet been forwarded. Recent research suggests that a dysregulated hypothalamic-pituitary-adrenal axis (HPA) may be contributory, and in particular that there may be diminished forward drive and adrenal under-stimulation.

In this preliminary study we wished to examine a cohort of CFS patients in whom evidence for such hypofunctioning was found. Our aim was to establish whether these patients had altered adrenal gland size.

Patients were recruited from a fatigue clinic. Those who fulfilled the Centre for Disease Control and Prevention (CDC) criteria underwent a 1 microgram adrenocorticotropin (ACTH) stimulation test, a test of adrenal gland functioning.

Eight subjects (five females, three males) with a subnormal response to this test underwent a computer tomography (CT) adrenal gland assessment. Measurements were compared with those from a group of 55 healthy subjects.

The right and left adrenal gland bodies were reduced by over 50% in the CFS subjects indicative of significant adrenal atrophy in a group of CFS patients with abnormal endocrine parameters.

This is the first study to use imaging methods to measure adrenal gland size in CFS. It is a limitation of this study that a selected CFS sample was employed. A future larger study would optimally employ an unselected cohort of CFS patients. This study has implications not only for the elucidation of CFS pathophysiology, but also for possible therapeutic strategies.

 

Source: Scott LV, Teh J, Reznek R, Martin A, Sohaib A, Dinan TG. Small adrenal glands in chronic fatigue syndrome: a preliminary computer tomography study. Psychoneuroendocrinology. 1999 Oct;24(7):759-68. http://www.ncbi.nlm.nih.gov/pubmed/10451910

 

Patterns of orthostatic intolerance: the orthostatic tachycardia syndrome and adolescent chronic fatigue

Abstract:

OBJECTIVES: To describe the orthostatic tachycardia syndrome (OTS) in adolescents, similarities to and differences from chronic fatigue syndrome (CFS), and patterns of orthostatic intolerance during head-up tilt (HUT).

STUDY DESIGN: Using electrocardiography and arterial tonometry, we investigated the heart rate and blood pressure responses during HUT in 20 adolescents with OTS compared with 25 adolescents with CFS, 13 healthy control subjects, and 20 patients with simple faint.

RESULTS: Of the control subjects, 4 of 13 experienced typical vasovagal faints with an abrupt fall in blood pressure and heart rate, and 14 of 20 patients with simple faint experienced similar HUT responses. All patients with CFS (25/25) experienced severe orthostatic symptoms with syncope in 2 of 25, early orthostatic tachycardia during HUT in 16 of 23 (13/16 hypotensive), and delayed orthostatic tachycardia in 7 of 23 (6/7 hypotensive). Acrocyanosis and edema occurred in 18 of 25. Early orthostatic tachycardia occurred in 10 of 20 patients with OTS. Of these, 9 of 10 were hypotensive, but hypotension was delayed in 4 of 9. Delayed tachycardia occurred in 10 of 20 (all hypotensive). Acrocyanosis and edema occurred in most patients with CFS, fewer patients with OTS, and in one patient with simple faint. Orthostatic symptoms were similar but more severe in patients with CFS compared with patients with OTS.

CONCLUSIONS: Symptoms and patterns of orthostatic heart rate and blood pressure change in OTS overlap strongly with those of CFS. Orthostatic intolerance in OTS may represent an attenuated form of chronic fatigue pathophysiology.

 

Source: Stewart JM, Gewitz MH, Weldon A, Munoz J. Patterns of orthostatic intolerance: the orthostatic tachycardia syndrome and adolescent chronic fatigue. J Pediatr. 1999 Aug;135(2 Pt 1):218-25. http://www.ncbi.nlm.nih.gov/pubmed/10431117

 

Hypotension: a forgotten illness?

Abstract:

Low blood pressure is a frequently encountered phenomenon in clinical practice. Few practitioners in the Western world however regard chronic low blood pressure as a genuinely pathological disease state. Evidence is emerging that chronic hypotension is associated with considerable morbidity in the community. It has recently been implicated as the causative mechanism in patients with the chronic fatigue syndrome.

Identification of low blood pressure can prove problematic, so ambulatory blood pressure monitoring may prove a more reliable method both for determining mean blood pressure levels and for identifying episodes of marked hypotension. Low blood pressure is broadly divided into two categories, chronic constitutional hypotension and hypotension associated with abnormal postural control. The causes are examined and the clinical presentations are discussed. An approach to investigation and diagnosis is outlined, and current options regarding treatment and management are described. The clinical spectrum of low blood pressure is wide. From young patients with vagally mediated syncope or patients with iatrogenic hypotension to elderly patients with autonomic degenerative conditions, there exists a substantial body of patients with potentially avoidable or treatable morbidity. Such a group requires more rigorous scientific investigation and a more sympathetic clinical approach.

 

Source: Owens PE, O’Brien ET. Hypotension: a forgotten illness? Blood Press Monit. 1997 Dec;2(1):3-14. http://www.ncbi.nlm.nih.gov/pubmed/10234084

 

Downregulation of RNase L inhibitor correlates with upregulation of interferon-induced proteins (2-5A synthetase and RNase L) in patients with chronic fatigue immune dysfunction syndrome

Abstract:

Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) is a disorder characterized by debilitating fatigue associated with immunological abnormalities and cognitive impairments. The recently cloned RNase L Inhibitor (RLI) gene encodes a specific protein which is believed to regulate 2-5A synthetase and RNase L activity via the formation of a latent heterodimeric protein complex.

In the present study, we investigated the levels of 2-5A synthetase, RNase L and RLI in patients with CFIDS as compared to healthy controls. Quantitative Competitive PCR (Q/C PCR) analysis showed a statistically significant decrease in RLI mRNA present in the peripheral blood lymphocytes (PBL) of patients with CFIDS (n = 25, mean = 569, S.E = 154) as compared to RLI mRNA level present in peripheral blood lymphocytes (PBL) of healthy controls (n = 15, mean = 2296, S.E = 506; p < 0.0001).

The decrease in RLI mRNA in CFIDS individuals correlated directly with RLI and RLI: RNase L protein ratio while showing an inverse relationship to the 2-5A synthetase and RNase L activity. This RLI mRNA and protein deficiency in CFIDS patients may explain the increase in activity of RNase L found in CFIDS patients.

The unidirectional decrease in RLI message and protein levels in CFIDS individuals may contribute to the destabilization of the latent RLI:RNase L heterodimeric protein complex, resulting in the excessive activation of RNase L shown in this study.

The increased activation of RNase L may result in an increased cellular RNA turnover and subsequent inhibition of protein synthesis; thus resulting in general fatigue, myalgia muscle weakness and other symptomatologies shown in CFIDS patients.

Furthermore, this data supports the hypothesis that the antiviral 2-5 oligoadenylate synthetase (2-5OAS) overexpression in individuals with CFIDS correlates with an increase in RNase L activity and with a decrease in RNase L inhibitor.

 

Source: Vojdani A, Choppa PC, Lapp CW. Downregulation of RNase L inhibitor correlates with upregulation of interferon-induced proteins (2-5A synthetase and RNase L) in patients with chronic fatigue immune dysfunction syndrome. J Clin Lab Immunol. 1998;50(1):1-16. http://www.ncbi.nlm.nih.gov/pubmed/10189612

 

Orthostatic intolerance in the chronic fatigue syndrome

Abstract:

This study aims to investigate the prevalence and pathophysiology of orthostatic intolerance (OI) and its potential contribution to symptoms of a group of unselected patients with chronic fatigue syndrome (CFS).

Seventy five patients (65 women, 10 men) with CFS were evaluated. During an initial visit, a clinical suspicion as to the likelihood of observing laboratory evidence of OI was assigned. Laboratory investigation consisted of beat-to-beat recordings of heart rate, blood pressure (Finapres), and stroke volume (impedance cardiograph) while supine and during 80 degrees head-up tilt (HUT), during rhythmic deep breathing (6 breaths/min) and during the Valsalva maneuver. The responses of 48 age-matched healthy controls who had no history of OI were used to define the range of normal responses to these three maneuvers.

Forty percent of patients with CFS had OI during head-up tilt. Sixteen exhibited neurally-mediated syncope alone, seven tachycardia (> 35 bpm averaged over the whole of the head-up tilt) and six a mixture of tachycardia and syncope. Eight of 48 controls exhibited neurally-mediated syncope. The responses to the Valsalva maneuver and to deep breathing were similar in controls and patients. On average, the duration of disease and patient age were significantly less and the onset of symptoms was more often subacute in patients with OI than in those without OI.

We conclude that there exists a clinically identifiable subgroup of patients with CFS and OI that differs from control subjects and from those with CFS without OI for whom treatment specifically aimed at improving orthostatic tolerance may be indicated.

 

Source: Schondorf R, Benoit J, Wein T, Phaneuf D. Orthostatic intolerance in the chronic fatigue syndrome. J Auton Nerv Syst. 1999 Feb 15;75(2-3):192-201. http://www.ncbi.nlm.nih.gov/pubmed/10189122