Adolescent chronic fatigue syndrome; a follow-up study displays concurrent improvement of circulatory abnormalities and clinical symptoms

Worsening Symptoms Is Associated with Larger Cerebral Blood Flow Abnormalities during Tilt-Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Background and Objectives: During tilt testing, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients experience an abnormal reduction in cerebral blood flow (CBF). The relationship between this CBF reduction and symptom severity has not been examined in detail. Our hypothesis was that ME/CFS severity is related to the degree of the CBF reduction during tilt testing. Materials and Methods: First, from our database, we selected ME/CFS patients who had undergone assessments of ME/CFS symptomatology and tilt tests on the same day, one at the first visit and the second during a follow-up. The change in symptomatology was related to the change in CBF during the tilt test. Second, we combined the data of two previously published studies (n = 219), where disease severity as defined by the 2011 international consensus criteria (ICC) was available but not published. Results: 71 patients were retested because of worsening symptoms. The ICC disease severity distribution (mild-moderate-severe) changed from 51/45/4% at visit-1 to 1/72/27% at follow-up (p < 0.0001). The %CBF reduction changed from initially 19% to 31% at follow-up (p < 0.0001). Of 39 patients with stable disease, the severity distribution was similar at visit-1 (36/51/13%) and at follow-up (33/49/18%), p = ns. The %CBF reduction remained unchanged: both 24%, p = ns. The combined data of the two previously published studies showed that patients with mild, moderate, and severe disease had %CBF reductions of 25, 29, and 33%, respectively (p < 0.0001). Conclusions: Disease severity and %CBF reduction during tilt testing are highly associated in ME/CFS: a more severe disease is related to a larger %CBF reduction. The data suggest a causal relationship where a larger CBF reduction leads to worsening symptoms.

Health, Wellbeing, and Prognosis of Australian Adolescents with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Case-Controlled Follow-Up Study

Background: The purpose of this study was to follow-up an Australian cohort of adolescents newly-diagnosed with ME/CFS at a tertiary paediatric ME/CFS clinic and healthy controls over a mean period of two years (range 1–5 years) from diagnosis. Objectives were to (a) examine changes over time in health and psychological wellbeing, (b) track ME/CFS symptomatology and fulfillment of paediatric ME/CFS diagnostic criteria over time, and (c) determine baseline predictors of ME/CFS criteria fulfilment at follow-up. Methods: 34 participants aged 13–18 years (25 ME/CFS, 23 controls) completed standardised questionnaires at diagnosis (baseline) and follow-up assessing fatigue, sleep quality and hygiene, pain, anxiety, depression, and health-related quality of life. ME/CFS symptomatology and diagnostic criteria fulfilment was also recorded. Results: ME/CFS patients showed significant improvement in most health and psychological wellbeing domains over time, compared with controls who remained relatively stable. However, fatigue, pain, and health-related quality of life remained significantly poorer amongst ME/CFS patients compared with controls at follow-up. Sixty-five percent of ME/CFS patients at baseline continued to fulfil ME/CFS diagnostic criteria at follow-up, with pain the most frequently experienced symptom. Eighty-two percent of patients at follow-up self-reported that they still had ME/CFS, with 79% of these patients fulfilling criteria. No significant baseline predictors of ME/CFS criteria fulfilment at follow-up were observed, although pain experienced at baseline was significantly associated with criteria fulfilment at follow-up (R = 0.6, p = 0.02). Conclusions: The majority of Australian adolescents with ME/CFS continue to fulfil diagnostic criteria at follow-up, with fatigue, pain, and health-related quality of life representing domains particularly relevant to perpetuation of ME/CFS symptoms in the early years following diagnosis. This has direct clinical impact for treating clinicians in providing a more realistic prognosis and highlighting the need for intervention with young people with ME/CFS at the initial diagnosis and start of treatment.

Associations Between Autonomic and Orthostatic Self-report and Physician Ratings of Orthostatic Intolerance in Youth

PURPOSE

There is no known biological marker or physical assessment to diagnose chronic fatigue syndrome (CFS), leaving physicians to heavily rely on self-report measures regarding the symptoms associated with CFS. Common symptoms of CFS include difficulty sleeping, joint pain, headaches, sore throat, cognitive dysfunction, physical exhaustion, dizziness, and nausea. Because of the overlap among CFS symptoms and autonomic functioning, we examined the association between 2 self-report measures of orthostatic and autonomic symptoms and a physician's report of autonomic functioning (measures of changes in blood pressure and pulse) to further understand the association among autonomic functioning within individuals with symptoms of CFS.

METHODS

With data from an ongoing study, we used independent t tests and Pearson correlation tests to assess the association among the orthostatic domain from the DePaul Symptom Questionnaire, Autonomic Symptom Checklist composite scores, and the physician's assessment of orthostatic intolerance obtained from a sample of 191 participants, 42 who were healthy controls.

FINDINGS

No significant demographic differences were found between the CFS-like group and the healthy controls. Results indicate a significant correlation between orthostatic and autonomic functioning (r = 0.58) and a correlation with a low effect size among autonomic functioning and physician measures of orthostatic functioning (r = -0.01 to 0.29). However, fewer correlations were found between self-reported symptoms of orthostatic functioning and the physician's measures of orthostatic functioning.

IMPLICATIONS

These results suggest that although orthostatic dysfunction is reported in children and adolescents with CFS-like symptoms, the physical measures of autonomic functioning in this study were unable to detect these symptoms.

Use of respiratory rates and heart rate variability in the assessment and treatment of children and adolescents with functional somatic symptoms

Functional somatic symptoms (FSS) emerge when the stress system is activated in response to physical or emotional stress that is either chronic or especially intense. In such cases, the heightened state of physiological arousal and motor activation can be measured through biological markers. Our team have integrated the use of biological markers of body state - respiratory rate, heart rate (HR) and heart rate variability (HRV) measurements - as a way of helping families to understand how physical symptoms can signal activation of the body's stress systems. This study measured respiratory rates, HR and HRV in children and adolescents with FSS (and healthy controls) during baseline assessment to determine whether these biological markers were effective at differentiating patients with FSS. The study also implemented a biofeedback intervention during the assessment to determine whether patients with FSS were able to slow their respiratory rates and increase HRV. Patients with FSS had faster respiratory rates, faster HR, and lower HRV, suggesting activation of the autonomic nervous system coupled with activation of the respiratory motor system. Like controls, patients were able to slow their respiratory rates, but in contrast to controls, they were unable to increase their HRV. Our findings suggest that patients with FSS present in a state of physiological activation and struggle to regulate their body state. Patients with FSS are likely to need ongoing training and practice to regulate body state coupled with interventions that target regulatory capacity across multiple systems.

Altered neuroendocrine control and association to clinical symptoms in adolescent chronic fatigue syndrome: a cross-sectional study

BACKGROUND

Chronic fatigue syndrome (CFS) is a common and disabling disorder, and a major threat against adolescent health. The pathophysiology is unknown, but alteration of neuroendocrine control systems might be a central element, resulting in attenuation of the hypothalamus-pituitary-adrenalin (HPA) axis and enhancement of the sympathetic/adrenal medulla (SAM) system. This study explored differences in neuroendocrine control mechanisms between adolescent CFS patients and healthy controls, and whether characteristics of the control mechanisms are associated with important clinical variables within the CFS group.

METHODS

CFS patients 12-18 years of age were recruited nation-wide to a single referral center as part of the NorCAPITAL project. A broad case definition of CFS was applied. A comparable group of healthy controls were recruited from local schools. A total of nine hormones were assayed and subjected to network analyses using the ARACNE algorithm. Symptoms were charted by a questionnaire, and daily physical activity was recorded by an accelerometer.

RESULTS

A total of 120 CFS patients and 68 healthy controls were included. CFS patients had significantly higher levels of plasma norepinephrine, plasma epinephrine and plasma FT4, and significantly lower levels of urine cortisol/creatinine ratio. Subgrouping according to other case definitions as well as adjusting for confounding factors did not alter the results. Multivariate linear regression models as well as network analyses revealed different interrelations between hormones of the HPA axis, the SAM system, and the thyroid system in CFS patients and healthy controls. Also, single hormone degree centrality was associated with clinical markers within the CFS group.

CONCLUSION

This study reveals different interrelation between hormones of the HPA axis, the SAM system, and the thyroid system in CFS patients and healthy controls, and an association between hormone control characteristics and important clinical variables in the CFS group. These results add to the growing insight of CFS disease mechanisms. Trial registration Clinical Trials NCT01040429.

Maintenance of Chronic Fatigue Syndrome (CFS) in Young CFS Patients Is Associated with the 5-HTTLPR and SNP rs25531 A > G Genotype

Earlier studies have shown that genetic variability in the SLC6A4 gene encoding the serotonin transporter (5-HTT) may be important for the re-uptake of serotonin (5-HT) in the central nervous system. In the present study we investigated how the 5-HTT genotype i.e. the short (S) versus long (L) 5-HTTLPR allele and the SNP rs25531 A > G affect the physical and psychosocial functioning in patients with chronic fatigue syndrome (CFS). All 120 patients were recruited from The Department of Paediatrics at Oslo University Hospital, Norway, a national referral center for young CFS patients (12–18 years). Main outcomes were number of steps per day obtained by an accelerometer and disability scored by the Functional Disability Inventory (FDI). Patients with the 5-HTT SS or SL_G genotype had a significantly lower number of steps per day than patients with the 5-HTT L_AL_G, SL_A or L_AL_A genotype. Patients with the 5-HTT SS or SL_G genotype also had a significantly higher FDI score than patients with the 5-HTT L_AL_G, SL_A or L_AL_A genotype. Thus, CFS patients with the 5-HTT SS or SL_G genotype had worse 30 weeks outcome than CFS patients with the 5-HTT L_AL_G, SL_A or L_AL_A genotype. The present study suggests that the 5-HTT genotype may be a factor that contributes to maintenance of CFS.

Effects of low-dose clonidine on cardiovascular and autonomic variables in adolescents with chronic fatigue: a randomized controlled trial

Background

Chronic Fatigue Syndrome (CFS) is a common and disabling condition in adolescence with few treatment options. A central feature of CFS is orthostatic intolerance and abnormal autonomic cardiovascular control characterized by sympathetic predominance. We hypothesized that symptoms as well as the underlying pathophysiology might improve by treatment with the alpha_2A–adrenoceptor agonist clonidine.

Methods

A total of 176 adolescent CFS patients (12–18 years) were assessed for eligibility at a single referral center recruiting nation-wide. Patients were randomized 1:1 by a computer system and started treatment with clonidine capsules (25 μg or 50 μg twice daily, respectively, for body weight below/above 35 kg) or placebo capsules for 9 weeks. Double-blinding was provided. Data were collected from March 2010 until October 2012 as part of The Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial (NorCAPITAL). Effect of clonidine intervention was assessed by general linear models in intention-to-treat analyses, including baseline values as covariates in the model.

Results

A total of 120 patients (clonidine group n = 60, placebo group n = 60) were enrolled and started treatment. There were 14 drop-outs (5 in the clonidine group, 9 in the placebo group) during the intervention period. At 8 weeks, the clonidine group had lower plasma norepinephrine (difference = 205 pmol/L, p = 0.05) and urine norepinephrine/creatinine ratio (difference = 3.9 nmol/mmol, p = 0.002). During supine rest, the clonidine group had higher heart rate variability in the low-frequency range (LF-HRV, absolute units) (ratio = 1.4, p = 0.007) as well as higher standard deviation of all RR-intervals (SDNN) (difference = 12.0 ms, p = 0.05); during 20° head-up tilt there were no statistical differences in any cardiovascular variable. Symptoms of orthostatic intolerance did not change during the intervention period.

Conclusions

Low-dose clonidine reduces catecholamine levels in adolescent CFS, but the effects on autonomic cardiovascular control are sparse. Clonidine does not improve symptoms of orthostatic intolerance.

Trial registration

Clinical Trials ID: NCT01040429, date of registration 12/28/2009.

Functional somatic symptoms in childhood and adolescence

PURPOSE OF REVIEW

Functional somatic symptoms (FSS) are common in children and adolescents, but explanatory models that synthesize research findings are lacking. This article reviews the studies published from January 2012 to March 2013 that investigate the neurophysiological mechanisms that may underlie FSS.

RECENT FINDINGS

Studies from diverse medical disciplines suggest that FSS are associated with functional differences in hypothalamic-pituitary-adrenal function, imbalances in vagal-sympathetic tone, upregulation of immune-inflammatory function, and primed cognitive-emotional responses that serve to amplify reactivity to threatening stimuli, thereby contributing to the subjective experience of somatic symptoms.

SUMMARY

FSS appear to reflect dysregulations of the stress system. When seemingly disparate research findings are interpreted together within an overarching 'stress-system' framework, a coherent explanatory model begins to emerge.

Relationship between autonomic cardiovascular control, case definition, clinical symptoms, and functional disability in adolescent chronic fatigue syndrome: an exploratory study

Chronic Fatigue Syndrome (CFS) is characterized by severe impairment and multiple symptoms. Autonomic dysregulation has been demonstrated in several studies. We aimed at exploring the relationship between indices of autonomic cardiovascular control, the case definition from Centers for Disease Control and Prevention (CDC criteria), important clinical symptoms, and disability in adolescent chronic fatigue syndrome. 38 CFS patients aged 12–18 years were recruited according to a wide case definition (ie. not requiring accompanying symptoms) and subjected to head-up tilt test (HUT) and a questionnaire. The relationships between variables were explored with multiple linear regression analyses. In the final models, disability was positively associated with symptoms of cognitive impairments (p<0.001), hypersensitivity (p<0.001), fatigue (p=0.003) and age (p=0.007). Symptoms of cognitive impairments were associated with age (p=0.002), heart rate (HR) at baseline (p=0.01), and HR response during HUT (p=0.02). Hypersensitivity was associated with HR response during HUT (p=0.001), high-frequency variability of heart rate (HF-RRI) at baseline (p=0.05), and adherence to the CDC criteria (p=0.005). Fatigue was associated with gender (p=0.007) and adherence to the CDC criteria (p=0.04). In conclusion, a) The disability of CFS patients is not only related to fatigue but to other symptoms as well; b) Altered cardiovascular autonomic control is associated with certain symptoms; c) The CDC criteria are poorly associated with disability, symptoms, and indices of altered autonomic nervous activity.