A Systematic Review of Biological Mechanisms of Fatigue in Chronic Illness

Abstract

Fatigue, a commonly reported symptom, is defined as an overwhelming, debilitating, and sustained sense of exhaustion that decreases the ability to function and carry out daily activities. To date, cancer researchers have been in the forefront in investigating the possible biological mechanisms of fatigue, identifying inflammation, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, and activation of the autonomic nervous system. The purpose of this systematic review is to describe fatigue and what is known about the biological mechanisms described in cancer in five chronic, noninfectious illnesses: heart failure, multiple sclerosis, chronic kidney disease, rheumatoid arthritis, and chronic obstructive pulmonary disease. We searched PubMed and EMBASE using fatigue as a major Medical subject headings (MeSH) heading with each individual disease added as a search term followed by each biological mechanism. We included only primary research articles published in English between 1996 and 2016 describing studies conducted in adult humans. We identified 26 relevant articles. While there is some evidence that the biological mechanisms causing fatigue in cancer are also associated with fatigue in other chronic illnesses, more research is needed to explore inflammation, the HPA axis, and the autonomic nervous system, and other mechanisms in relation to fatigue in a variety of chronic illnesses.

Fatigue in Nondialysis Chronic Kidney Disease: Correlates and Association with Kidney Outcomes

“…Of note, as previously reported, only 50% of individuals with MDD in this cohort were prescribed antidepressant medications at baseline, so such treatment should not be considered a proxy for the presence of depression [38]. This finding could be explained by collinearity between depression and fatigue in patients with CKD-ND, due either to a direct effect of depression on symptoms of fatigue or a common underlying pathway such as elevated systemic inflammation [39]. The QIDS-Am J Nephrol 2019;50:37-47 DOI: 10.1159/000500668 SR 16 identified fatigue in a lower proportion of the sample than the other measures, but may be more selective for identifying individuals at future risk for poor outcomes.…”

Patients experience of fatigue in advanced heart failure

“…Descriptions from our study participants related to both negative and positive feelings may provide insight for support strategies related to psychological effects of worsening fatigue in later stages of heart failure. Alleviation of fatigue through social interaction has been seen previously (Falk et al 2007;Matura et al 2018) Participant narratives elucidated differences in how they managed periods of fatigue and adapted their daily life to accommodate chronic or worsening fatigue. Although most participants discussed negative emotional feelings regarding fatigue, very few said it was easier to "give up" or "withdraw" from activities; the majority focused on ways to manage their self-care.…”

The Inflammatory Bowel Disease-Fatigue Patient Self-Assessment Scale: Translation, Cross-Cultural Adaptation and Psychometric Properties of the Brazilian Version (Ibd-F Brazil)

“…This study has limitations. First, the recruitment of participants with IBD was conducted from single center, however, the participant's characteristics were similar in age and disease duration reported in previous studies also carried out in the general IBD population (4,6,7) . Second, the IBD-F was originally self-administered by the study participants.…”

“…General fatigue is a prevalent symptom affecting about 40% of patients in remission and also in about 86% in the active phase of the disease (4) . Fatigue is defined as a feeling of exhaustion, lack of energy, debilitating and of prolonged duration, affecting functional capacity and performance in activities of daily living (5,6) . In the IBD diseases, fatigue has been show to be associated with significant impairment in physical function and health-related quality of life (7,8) .…”