Introduction:
Fatigue is a common complaint experienced by most of subjects during lifetime, which affects approximately 30–50% of general population as point prevalence.1 According to the fatigue-lasting duration, it is classified as acute (<1 month), prolonged (>1 month, <6 months), and chronic fatigue (≥6 months), respectively. Acute fatigue is generally disappears after taking a rest or treating the causative diseases, while uncontrolled prolonged and chronic fatigue limit the physical and social activities.2 Especially, medically unexplained chronic fatigue is a debilitating status, such as idiopathic chronic fatigue (ICF) and chronic fatigue syndrome (CFS).
Source: Son CG. Differential diagnosis between “chronic fatigue” and “chronic fatigue syndrome”. Integr Med Res. 2019 Jun;8(2):89-91. doi: 10.1016/j.imr.2019.04.005. Epub 2019 Apr 12. PMID: 31193269; PMCID: PMC6522773. https://pmc.ncbi.nlm.nih.gov/articles/PMC6522773/ (Full text)