TGI Friday! Our weekly round-up of recently published research abstracts and news | 9 November 2012

From BMC Infectious Diseases (open access) 2012 Oct 30;12(1):280. [Epub ahead of print]

Assessing the long-term health impact of Q-fever in the Netherlands: a prospective cohort study started in 2007 on the largest documented Q-fever outbreak to date.

van Loenhout JA (1*), Paget WJ (1,2), Vercoulen JH (3), Wijkmans CJ (1,4), Hautvast JL (1), van der Velden K(1).

1) Academic Collaborative Centre AMPHI, Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
2) Netherlands Institute for Health Services Research (NIVEL), Utrecht, the Netherlands
3) Department of Medical Psychology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
4) Department of Infectious Disease Control, Municipal Health Service Hart voor Brabant, ‘s-Hertogenbosch, the Netherlands

Abstract

BACKGROUND

Between 2007 and 2011, the Netherlands experienced the largest documented Q-fever outbreak to date with a total of 4108 notified acute Q-fever patients. Previous studies have indicated that Q-fever patients may suffer from long-lasting health effects, such as fatigue and reduced quality of life.

Our study aims to determine the long-term health impact of Qfever. It will also compare the health status of Q-fever patients with three reference groups: 1) healthy controls, 2) patients with Legionnaires’ disease and 3) persons with a Q-fever infection but a-specific symptoms.

METHODS/DESIGN

Two groups of Q-fever patients were included in a prospective cohort study. In the first group the onset of illness was in 2007-2008 and participation was at 12 and 48 months. In the second group the onset of illness was in 2010-2011 and participation was at 6 time intervals, from 3 to 24 months. The reference groups were included at only one time interval. The subjective health status, fatigue status and quality of life of patients will be assessed using two validated quality of life questionnaires.

DISCUSSION

This study is the largest prospective cohort study to date that focuses on the effects of acute Q-fever. It will determine the long-term (up to 4 years) health impact of Q-fever on patients and compare this to three different reference groups so that we can present a comprehensive assessment of disease progression over time.


From the Korean Journal of Family Medicine 2012 Sep;33(5):320-5. doi:
10.4082/kjfm.2012.33.5.320. Epub 2012 Sep 27.

Improved chronic fatigue symptoms after removal of mercury in patient with increased mercury concentration in hair toxic mineral assay: a case.

Shin SR, Han AL.
Department of Family Medicine, Wonkwang University College of Medicine, Iksan, Korea.

Abstract

Clinical manifestations of chronic exposure to organic mercury usually have a gradual onset.

As the primary target is the nervous system, chronic mercury exposure can cause symptoms such as fatigue, weakness, headache, and poor recall and concentration. In severe cases chronic exposure leads to intellectual deterioration and neurologic abnormality.

Recent outbreaks of bovine spongiform encephalopathy and pathogenic avian influenza have increased fish consumption in Korea.

Methyl-mercury, a type of organic mercury, is present in higher than normal ranges in the general Korean population.

When we examine a patient with chronic fatigue, we assess his/her methyl-mercury concentrations in the body if environmental exposure such as excessive fish consumption is suspected. In the current case, we learned the patient had consumed many slices of raw tuna and was initially diagnosed with chronic fatigue syndrome.

Therefore, we suspected that he was exposed to methyl-mercury and that the mercury concentration in his hair would be below the poisoning level identified by World Health Organization but above the normal range according to hair toxic mineral assay.

Our patient’s toxic chronic fatigue symptoms improved after he was given mercury removal therapy, indicating that he was correctly diagnosed with chronic exposure to organic mercury.


Note (courtesy of Kelly Latta, who regularly gathers research updates for Co-Cure): The results of this small study would need to be validated in a larger study. Because the study used a custom built means of objective monitoring it may make it difficult to replicate by other researchers. Comparison with other forms of arthritis or ME and CFS might also be
appropriate.

From Arthritis Research and Therapy (open access) 2012 Nov 1;14(6):R236. [Epub ahead of print]

Noninvasive optical characterization of muscle blood flow, oxygenation, and metabolism in women with fibromyalgia.

Shang Y (1), Gurley K(1), Symons B(2), Long D(3), Srikuea R(3,4), Crofford LJ(5), Peterson CA(3), Yu G(1,*).

1) Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA.
2) Department of Gerontology, College of Public Health, University of Kentucky, Lexington, KY 40536, USA.
3) College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA.
4) Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
5) Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
*Corresponding author: guoqiang.yu@uky.edu

Abstract

INTRODUCTION

Women with fibromyalgia (FM) have symptoms of increased muscular fatigue and reduced exercise tolerance, which may be associated with alterations in muscle microcirculation and oxygen metabolism.

This study used near-infrared diffuse optical spectroscopies to noninvasively evaluate muscle blood flow, blood oxygenation and oxygen metabolism during leg fatiguing exercise and during arm arterial cuff occlusion in post-menopausal women with and without FM.

METHODS

Fourteen women with FM and twenty-three well-matched healthy controls participated in this study. For the fatiguing exercise protocol, thesubject was instructed to perform 6 sets of 12 isometric contractions of knee extensor muscles with intensity steadily increasing from 20 to70% maximal voluntary isometric contraction (MVIC).

For the cuff occlusion protocol, forearm arterial blood flow wasoccluded via a tourniquet on the upper arm for 3 minutes.

Leg or arm muscle hemodynamics, including relative blood flow (rBF),oxy- and deoxy-hemoglobin concentration ([HbO2] and [Hb]), totalhemoglobin concentration (THC) and blood oxygen saturation (StO2), were continuously monitored throughout protocols using a custom-built hybrid diffuse optical instrument that combined a commercial near-infrared oximeter for tissue oxygenation measurements and a custom-designed diffuse correlation spectroscopy (DCS) flowmeter for tissue blood flow measurements.

Relative oxygen extraction fraction (rOEF) and oxygen consumption rate (rV.O2) were calculated from the measured blood flow and oxygenation data. Post-manipulation (fatiguing exercise or cuff occlusion) recovery in muscle hemodynamics was characterized by the recovery half-time, a time interval from the end of manipulation to the time that tissue hemodynamics reached a half-maximal value.

RESULTS

Subjects with FM had similar hemodynamic and metabolic response/recovery patterns as healthy controls during exercise and during arterial occlusion.

However, tissue rOEF during exercise in subjects with FM was significantly lower than in healthy controls, and the half-times of oxygenation recovery (Delta[HbO2] and Delta[Hb]) were significantly longer following fatiguing exercise and cuff occlusion.

CONCLUSIONS

Our results suggest an alteration of muscle oxygen utilization in the FM population. This study demonstrates the potential of using combined diffuse optical spectroscopies (i.e., NIRS/DCS) to comprehensively evaluate tissue oxygen and flow kinetics in skeletal muscle.


From Proceedings of the Mayo Clinic (open access) 2 November 2012. pii: S0025-6196(12)00896-8. doi:10.1016/j.mayocp.2012.08.013.

Postural Tachycardia Syndrome: A Heterogeneous and Multifactorial Disorder.

Benarroch EE.
Department of Neurology, Mayo Clinic, Rochester, MN.

Abstract

Postural tachycardia syndrome (POTS) is defined by a heart rate increment of 30 beats/min or more within 10 minutes of standing or head-up tilt in the absence of orthostatic hypotension; the standing heart rate is often 120 beats/min or higher. POTS manifests with symptoms of cerebral hypoperfusion and excessive sympathoexcitation.

The pathophysiology of POTS is heterogeneous and includes impaired sympathetically mediated vasoconstriction, excessive sympathetic drive, volume dysregulation, and deconditioning.

POTS is frequently included in the differential diagnosis of chronic unexplained symptoms, such as inappropriate sinus tachycardia, chronic fatigue, chronic dizziness, or unexplained spells in otherwise healthy young individuals.

Many patients with POTS also report symptoms not attributable to orthostatic intolerance, including those of functional gastrointestinal or bladder disorders, chronic headache, fibromyalgia, and sleep disturbances.

In many of these cases, cognitive and behavioral factors, somatic hypervigilance associated with anxiety, depression, and behavioral amplification contribute to symptom chronicity.

The aims of evaluation in patients with POTS are to exclude cardiac causes of inappropriate tachycardia; elucidate, if possible, the most likely pathophysiologic basis of postural intolerance; assess for the presence of treatable autonomic neuropathies; exclude endocrine causes of a hyperadrenergic state; evaluate for cardiovascular deconditioning; and determine the contribution of emotional and behavioral factors to the patient’s symptoms.

Management of POTS includes avoidance of precipitating factors, volume expansion, physical countermaneuvers, exercise training, pharmacotherapy (fludrocortisone, midodrine, β-blockers, and/or pyridostigmine), and behavioral-cognitive therapy.

A literature search of PubMed for articles published from January 1, 1990, to June 15, 2012, was performed using the following terms (or combination of terms): POTS; postural tachycardia syndrome, orthostatic; orthostatic; syncope; sympathetic; baroreceptors; vestibulosympathetic; hypovolemia; visceral pain; chronic fatigue; deconditioning; headache; Chiari malformation; Ehlers-Danlos; emotion; amygdala; insula; anterior cingulate; periaqueductal gray; fludrocortisone; midodrine; propranolol; β-adrenergic; and pyridostigmine.

Studies were limited to those published in English. Other articles were identified from bibliographies of the retrieved articles.


AUSTRALIAN RESEARCH VOLUNTEERS WANTED

Volunteers are still needed for an Australian study into the levels of carnitines and fatty acids (important compounds in energy production) in people with chronic fatigue syndrome at the University of South Australia in Adelaide. Details HERE.

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