Idiopathic chronic fatigue

Idopathic chronic fatigue or ICF is long lasting chronic fatigue that is not caused by an underlying medical condition or psychiatric illness. Patients with idopathic chronic fatigue do not fulfill 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 has 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? (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