Idiopathic chronic fatigue

Idiopathic chronic fatigue or ICF is long lasting chronic fatigue that is not caused by an underlying medical condition or psychiatric illness. Patients with idiopathic chronic fatigue do not fulfil the criteria for chronic fatigue syndrome (CFS). The word idiopathic reflects an unknown underlying cause, meaning that the chronic fatigue is a medically unexplained symptom.

Differences from chronic fatigue syndrome
[[File:ChronicFatigueSyndrome-IdiopathicChronicFatigue-Differences.jpg|left|thumb|Chronic Fatigue Syndrome (CFS) is a distinct neurological disease, and is not the same as chronic fatigue, or long-term fatigue with no known cause (ICF).

''Source: Son, C-G (2019). Differential diagnosis between “chronic fatigue” and “chronic fatigue syndrome”. Integrative Medicine Research, 8(2), 89-91. Suggested algorithm for chronic fatigue, ICF and CFS. License: CC-BY-ND-NC.'']]


 * Idiopathic chronic fatigue is not a distinct illness or disease.


 * Idiopathic chronic fatigue only requires the symptom of chronic fatigue.
 * Idiopathic chronic fatigue is more common in the elderly and becomes more common with ageing.
 * Chronic fatigue syndrome is a neurological disease.
 * Chronic fatigue syndrome is a multi-systemic illness with a wide variety of symptoms, which may include: immune symptoms, cardiovascular symptoms, post-exertional malaise, headaches or migraines, and chronic pain.
 * Chronic fatigue syndrome is most common in teenagers and working age adults.
 * Idiopathic chronic fatigue is generally considered less disabling.

Notable studies

 * 1992, Chronic tiredness and idiopathic chronic fatigue--a connection? - (Abstract)
 * 1999, Idiopathic chronic fatigue and chronic fatigue syndrome: a comparison of two case-definitions - (Abstract)
 * 2004, Disability in chronic fatigue syndrome and idiopathic chronic fatigue - (Full text)
 * 2007/updated 2009, Traditional Chinese medicinal herbs for idiopathic chronic fatigue and chronic fatigue syndrome - (Full text)
 * 2012, Fatigue severity of patients with idiopathic chronic fatigue compared to healthy subjects - (Full text)
 * 2013, Idiopathic chronic fatigue in older adults is linked to impaired mitochondrial content and biogenesis signaling in skeletal muscle - (Full text)
 * 2013, Chronic fatigue syndrome 5 years after giardiasis: differential diagnoses, characteristics and natural course - (Full text)
 * 2013, An open-label study of effects of acupuncture on chronic fatigue syndrome and idiopathic chronic fatigue: study protocol for a randomized controlled trial - (Full text)
 * 2014, Chronic fatigue syndrome: A review (Full Text)
 * 2016, Metabolic Rate and Perceived Exertion of Walking in Older Adults With Idiopathic Chronic Fatigue (Full text)
 * 2019, Differential diagnosis between “chronic fatigue” and “chronic fatigue syndrome” - (Full source)

Learn more

 * 19 Important Causes of Fatigue – Tiredness and Chronic Fatigue Explained