Chronic fatigue syndrome. 1: Etiology and pathogenesis

Systematic review of randomized controlled trials for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)

BACKGROUND

Although medical requirements are urgent, no effective intervention has been proven for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). To facilitate the development of new therapeutics, we systematically reviewed the randomized controlled trials (RCTs) for CFS/ME to date.

METHODS

RCTs targeting CFS/ME were surveyed using two electronic databases, PubMed and the Cochrane library, through April 2019. We included only RCTs that targeted fatigue-related symptoms, and we analyzed the data in terms of the characteristics of the participants, case definitions, primary measurements, and interventions with overall outcomes.

RESULTS

Among 513 potentially relevant articles, 55 RCTs met our inclusion criteria; these included 25 RCTs of 22 different pharmacological interventions, 28 RCTs of 18 non-pharmacological interventions and 2 RCTs of combined interventions. These studies accounted for a total of 6316 participants (1568 males and 4748 females, 5859 adults and 457 adolescents). CDC 1994 (Fukuda) criteria were mostly used for case definitions (42 RCTs, 76.4%), and the primary measurement tools included the Checklist Individual Strength (CIS, 36.4%) and the 36-item Short Form health survey (SF-36, 30.9%). Eight interventions showed statistical significance: 3 pharmacological (Staphypan Berna, Poly(I):poly(C12U) and CoQ10 + NADH) and 5 non-pharmacological therapies (cognitive-behavior-therapy-related treatments, graded-exercise-related therapies, rehabilitation, acupuncture and abdominal tuina). However, there was no definitely effective intervention with coherence and reproducibility.

CONCLUSIONS

This systematic review integrates the comprehensive features of previous RCTs for CFS/ME and reflects on their limitations and perspectives in the process of developing new interventions.

Neurasthenia, subjective health complaints and sensitization

Patients (n=997) visiting general practitioners in an area in Western Norway completed a battery of questionnaires related to subjective health complaints and fatigue. An additional 78 patients were referred directly to the hospital for neurasthenia. After screening the questionnaires and interviews with a selected sample, a total of 73 patients were finally accepted as 'neurasthenia' patients satisfying the ICD-10 diagnosis. These patients were compared with the remaining 1002 patients. Patients with neurasthenia had more prevalent and more severe subjective health complaints, particularly pseudoneurological and musculoskeletal complaints than the reference population of patients. They reported low levels of instrumental coping and poorer physical fitness, in spite of a comparable level of self reported physical activity and exercise. Women were over-represented in this group. This overall higher score on subjective complaints from all organ systems is in accordance with the hypothesis of an overall and general sensitization to the afferent inputs from their psychophysiological systems.

Atypical depression as a secondary symptom in chronic fatigue syndrome

Chronic fatigue syndrome (CFS) has gained prominence since 1988 and a substantial amount of research has been done in this domain. However, it is still regarded as a controversial condition. Moreover, most of the symptoms of CFS itself are non-specific, occurring in many illnesses; some of the symptoms are also common in depression. Indeed, an area of continued controversy and debate involves the diagnostic overlap between CFS and psychiatric disorders. Through anecdotal evidence, atypical depression appears to be common in CFS. Recent developments in psychobiology underscore the role of the acute phase response and its associated sickness behavior in affective disorders. Thus, we hypothesize that atypical depression is sickness behavior rather than an affective disorder as shown by anecdotal evidence in CFS.

Subclassifying chronic fatigue syndrome through exercise testing

PURPOSE

The purpose of this study was to examine physiological responses of persons with chronic fatigue syndrome (CFS) to a graded exercise test.

METHODS

Cardiopulmonary exercise tests were performed on 189 patients diagnosed with CFS. Based on values for peak oxygen consumption, patients were assigned to one of four impairment categories (none, mild, moderate, and severe), using American Medical Association (AMA) guidelines. A one-way MANOVA was used to determine differences between impairment categories for the dependent variables of age, body mass index, percentage of predicted [OV0312]O(2), resting and peak heart rates, resting and peak systolic blood pressure, respiratory quotient (RQ), and rating of perceived exertion.

RESULTS

Significant differences were found between each impairment level for percentage of predicted [OV0312]O(2) and peak heart rate. Peak systolic blood pressure values for the "moderate," and "severe" groups differed significantly from each other and both other groups. The more impaired groups had lower values. The no impairment group had a significantly higher peak RQ than each of the other impairment levels (all P < 0.001). Peak [OV0312]O(2) values were less than predicted for all groups. Compared with the males, the women achieved actual values for peak [OV0312]O(2) that were closer to their predicted values.

CONCLUSION

Despite a common diagnosis, the functional capacity of CFS patients varies greatly. Stratifying patients by function allows for a more meaningful interpretation of the responses to exercise and may enable differential diagnosis between subsets of CFS patients.

Neuropsychological functioning in chronic fatigue syndrome: a review

OBJECTIVE

In this paper we review critically the current status of neurocognitive studies in patients with chronic fatigue syndrome (CFS).

METHOD

CFS literature was monitored as part of a large research project which involved several neuropsychological and psychopathological studies. The literature survey was the result of several consecutive searches on Medline and PsycInfo databases.

RESULTS

The neurocognitive studies are reviewed in terms of scientificaly accepted aspects of attention and memory. In addition, we review possible explanations for cognitive dysfunction in CFS. This is preceded with a discussion of the methodological limitations that are considered to explain inconcistencies across neuropsychological studies in CFS.

CONCLUSION

The current research shows that slowed processing speed, impaired working memory and poor learning of information are the most prominent features of cognitive dysfunctioning in patients with CFS. Furthermore, to this date no specific pattern of cerebral abnormalities has been found that uniquely characterizes CFS patients. There is no overwhelming evidence that fatigue is related to cognitive performance in CFS, and researchers agree that their performance on neuropsychological tasks is unlikely to be accounted solely by the severity of the depression and anxiety.

Chronic fatigue syndrome: a matter of enzyme deficiencies?

The etiology of chronic fatigue syndrome (CFS) remains an enigma. But literature concerning chronic fatigue which does not focus on CFS points to all sorts of enzyme deficiencies as possible causes. The deficiencies are probably dismissed as causes of CFS because other characteristic symptoms are lacking in CFS patients. But these symptoms are often also lacking in patients with a deficiency. Symptom patterns in enzyme deficiencies are extremely variable. Therefore, patients with CFS should be screened systematically for enzyme deficiencies.

The Experience of Living With Chronic Fatigue Syndrome

1. Chronic fatigue syndrome (CFS) is a condition that affects the total person, body, mind, and spirit. 2. CFS sufferers describe the experience as being in the illness, remembering life before the illness, and living with the symptoms. 3. Empathy and compassion are essential components of providing nursing care for clients with CFS.

The World Health Organization Quality of Life Assessment Instrument (WHOQOL-100): Validation Study with the Dutch Version

In this study, we examine the reliability and validity of a new quality-of-life (QoL) instrument, the Field Trial Version of the World Health Organization Quality of Life assessment instrument (WHOQOL-100). Two-hundred-and-twenty persons, 147 healthy individuals, and 73 chronic fatigue syndrome (CFS) patients completed the WHOQOL-100 and a test battery of related measures. The WHOOQL-100 has a fairly good internal consistency and a good validity.