Idiopathic chronic fatigue

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Idiopathic Chronic Fatigue
Other namesChronic Idiopathic Fatigue (CIF), insufficient/idiopathic fatigue (ISF), unexplained chronic fatigue
Symptomatic
Frequency6.2 to 64.2 per 1000[2]

Idiopathic chronic fatigue (ICF) or chronic

chronic fatigue syndrome.[4] Such fatigue is widely understood to have a profound effect on the lives of patients who experience it.[1][5]

Definition

ICF has been defined as a physical medical condition of unknown origin where CFS symptoms are not met.[6]

Classification

ICF does not have a dedicated diagnostic code in the World Health Organization's ICD-11 classification.[7]

ICF is sometimes diagnosed under physical symptom classifications such as MG22 (Fatigue) in the ICD-11, and R53.8 (Other malaise and fatigue) in the ICD-10. This allows ICF to be coded as fatigue or unspecified chronic fatigue, and help distinguish it from other forms of fatigue including cancer-related fatigue, chronic fatigue syndrome, fatigue due to depression, fatigue due to old age, weakness/

asthenia, and in the ICD-10, also from fatigue lasting under 6 months.[8]
[9] The ICD-11 MG22 Fatigue code is also shared with lethargy, and exhaustion, which may not be as long lasting.[7]

The WHO does not recognize any kind of fatigue-based psychiatric illness (unless it is accompanied by related psychiatric symptoms).[10][11]

Diagnosis

ICF is fatigue of unknown origin, persisting or relapsing for a minimum of six consecutive months, and failing to meet the criteria for

chronic fatigue syndrome.[6] There are no agreed upon international criteria for idiopathic chronic fatigue, however the CDC's 1994 Idiopathic Chronic Fatigue criteria, known as the Fukuda ICF criteria, are commonly used.[1][5]

Differential diagnosis

Differences from chronic fatigue

ICF differs from chronic fatigue since it is unexplained rather than linked to a medical or psychological illness (for example, diabetes or depression).[6] This means that ICF patients have reduced treatment options: there is no underlying disease or known cause that could be treated in order to reduce the degree of fatigue, which results in a poorer prognosis for ICF.[12]

In ICF, the fatigue lasts for a minimum of six months, but chronic fatigue is usually (but not always) considered to last for a minimum of six months to be considered chronic, and if lasting between one and six months it is considered prolonged fatigue.

Chronic fatigue is the term used when medical tests and a mental and physical assessment has not yet been carried out. ICF can only be diagnosed after these are done and the results show no underlying untreated cause.[6]

Differences from neurasthenia

  • Neurasthenia consists of a large number of symptoms, typically patients had a mix of physical and psychological complaints for example
    weariness. Fatigue was common but not essential.[13][14][15] ICF consists of the single symptom of fatigue, which may be either mental or physical or both, and may be described in many different ways including as "exhaustion".[6]

Differential diagnosis from chronic fatigue syndrome

Chronic fatigue syndrome (CFS) requires the additional symptoms of:

  1. post-exertional malaise (significantly worsening symptoms with activity which results in a significant reduction in daily activities, which may be delayed by up to 3 days
  2. sleep dysfunction
  3. either:

A range of other symptoms commonly result from CFS including headaches, muscle and joint pain and low-grade fever.[16]

ICF requires:

  1. only one symptom: chronic fatigue
  2. does not need a significant reduction in activities: some people are able to push through the fatigue to continue activities
  3. is only diagnosed if CFS symptoms are not met[6]

Prevalence of ICF is between 3-15%, which is two to ten times higher than CFS[12] Older age at onset is more common in ICF, particularly from age 50,[12] while in CFS age at onset is typically 16-35 years old[16]

The recovery rate within a year is significantly higher for ICF patients, 30-50% compared to under 10% in CFS[12][16]

ICF is categorized within general signs and symptoms by the World Health Organization,[7] while CFS is categorized as a neurological disease[17]

Ability to tolerate exertion including exercise has been shown to be greater in ICF patients compared to CFS patients, particularly on consecutive days, and this applies to both men and women.[18][19][20]

Severity of illness in ICF is typically less than in CFS, with some relatively small studies finding no severe ICF patients, the same studies found fibromyalgia was significantly less common in ICF.[19][20]

Signs and symptoms

  • Clinically evaluated fatigue
  • New or definite onset (not lifelong)
  • Fatigue persists or is relapsing for six consecutive months or longer
  • Fails to meet the criteria for
    chronic fatigue syndrome
  • The cause is unknown (not resulting from another medical condition)[1][6][5]

Exclusions

Common medical causes of fatigue

These must be ruled out before a diagnosis of ICF can be made.

Management

Idiopathic chronic fatigue is typically managed in general medicine rather than by referral to a specialist. There is no cure, no approved drug, and treatment options are limited.[21] Management may involve a form of counseling, or antidepressant medication, although some patients may prefer herbal or alternative remedies.[1]

Counseling

A form of counseling known as cognitive behavioral therapy may help some people manage or cope with idiopathic chronic fatigue.[1]

Medication

There are no approved drugs for ICF.[21]

Antidepressants

Antidepressants drugs such as tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) may be appropriate if symptoms are exacerbated by suspected or diagnosed serotonin related health issues, such as depression.[1]

Alternative and complementary treatments

Only limited trials had been conducted for alternative and complementary treatments; there is no clear evidence of these treatments being effective for ICF due to a lack of randomized controlled trials.[21]

Prognosis

Between 30% and just under 50% of patients recover within one year.[1][22]

Epidemiology

Fatigue is common in the general population and often caused by overwork, too much activity or a specific illness or disease. Around 20% of patients who visit their clinician report fatigue.[1] Prolonged fatigue is fatigue that persists for more than a month, and chronic fatigue is fatigue that lasts at least six consecutive months, which may be caused by a physical or psychological illness, or may be idiopathic (no known cause).[1] Chronic fatigue with a known cause is twice as common as idiopathic chronic fatigue.[6]

Idiopathic chronic fatigue affects between 2.4% and 6.42% of patients,[23] with females more likely to be affected than men.[1] Age at onset is typically over 50 years of age.[12] A significant number of patients present with idiopathic chronic fatigue as part of a mix of medically unexplained symptoms, while others present with a primary problem of fatigue alone.[1]

See also

References

  1. ^ .
  2. .
  3. .
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  5. ^ .
  6. ^ .
  7. ^ a b c d e "ICD-11 - Mortality and Morbidity Statistics | MG22 Fatigue". World Health Organization. 2019. Retrieved 2023-04-25. MG22 Fatigue
    A feeling of exhaustion, lethargy, or decreased energy, usually experienced as a weakening or depletion of one's physical or mental resource and characterised by a decreased capacity for work and reduced efficiency in responding to stimuli. Fatigue is normal following a period of exertion, mental or physical, but sometimes may occur in the absence of such exertion as a symptom of health conditions.
    Inclusions General physical deterioration Lethargy
    Exclusions Combat fatigue (QE84) Exhaustion due to exposure (NF07.2) heat exhaustion (NF01) Bodily distress disorder (6C20) Depressive disorders (6A70-6A7Z) Sleep-wake disorders (7A00-7B2Z) Bipolar or related disorders (6A60-6A6Z) senile fatigue (MG2A) Chronic fatigue syndrome (8E49) Myalgic encephalomyelitis (8E49) Postviral fatigue syndrome (8E49) pregnancy-related exhaustion and fatigue (JA65).
  8. ^ National Center for Health Statistics (April 1, 2023). "ICD-10-CM Official Guidelines for Coding and Reporting | FY 2023. Updated April 1, 2023" (PDF). p. 73. Retrieved 2023-04-25. Chapter 18: Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
    Chapter 18 includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded. Signs and symptoms that point to a specific diagnosis have been assigned to a category in other chapters of the classification.
  9. ^ a b "ICD-10 Version:2019 | R53". World Health Organization. Retrieved 2023-04-25. R53 Malaise and fatigue.
    R53.0 Neoplastic (malignant) related fatigue. R53.1 Weakness. Asthenia NOS.
    Excludes: age-related weakness (R54) muscle weakness (generalized) (M62.81) sarcopenia (M6 2.84) senile asthenia (R54)
    R53.2 Functional quadriplegia. Excludes: frailty NOS (R54), hysterical paralysis (F44.4), immobility syndrome (M62.3) neurologic quadriplegia (G82.5-) quadriplegia (G82.50).
    R53.8 Other malaise and fatigue
    Excludes: combat exhaustion and fatigue (F43.0) congenital debility (P96.9) exhaustion and fatigue due to excessive exertion (T73.3) exhaustion and fatigue due to exposure (T73.2) exhaustion and fatigue due to heat P'67.-) exhaustion and fatigue due to pregnancy (026.8-), exhaustion and fatigue due to recurrent depressive episode (F33) exhaustion and fatigue due to senile debility (R54)
    R53.81 Other malaise. Chronic debility Debility NOS. General physical deterioration. Malaise NOS. Nervous debility. Excludes: age-related physical debility (R54).
    R53.82 Chronic fatigue, unspecified. Excludes: chronic fatigue syndrome (G93.32) myalgic encephalomyelitis (G93.32) post infection and related fatigue syndromes (G93.39) postviral fatigue syndrome (G93.31)
    R53.83 Other fatigue
    Fatigue NOS. Lack of energy. Lethargy. Tiredness Excludes: exhaustion and fatigue due to depressive episode (F32.-)
    R54 Age-related physical debility.Frailty. Old age. Senescence. Senile asthenia. Senile debility. Excludes: age-related cognitive decline (R41.81) sarcopenia (M62.84) senile psychosis (F03) senilityNOS(R41.81).
    R55 Syncope and collapse...
  10. S2CID 149462235
    .
  11. .
  12. ^ .
  13. .
  14. ^ a b c WHO (2007). "Chapter V Mental and behavioural disorders (F00-F99)". Retrieved 2009-10-09.
  15. ^
    S2CID 253154697
    .
  16. ^ a b c "What is ME/CFS? | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)". Centers for Disease Control and Prevention. 12 July 2018. Archived from the original on 17 August 2020. Retrieved 21 May 2020.
  17. ^ 8EF9 - Postviral syndrome,Chronic fatigue syndrome, Myalgic Encephalomyelitis ICD-11. WHO. 2023-01.
  18. PMID 24456560
    .
  19. ^ .
  20. ^ .
  21. ^ .
  22. ^ Joyce J, Hotopf M, Wessely S. The prognosis of chronic fatigue and chronic fatigue syndrome: a systematic review. Quarterly Journal of Medicine 1997;90:223‐233.
  23. PMID 9314795
    .