Fatigue

===Association with diseases and illnesses===
Fatigue is often associated with diseases and conditions. Some major categories of conditions that often list fatigue as a symptom include physical diseases, substance use illness, mental illnesses, and other diseases and conditions.

====Physical diseases====

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* [[autoimmune disease]]s,<ref name="pmid31447842"/> such as [[celiac disease]], [[lupus]], [[multiple sclerosis]],<ref>{{cite journal | vauthors = Strober LB | title = Fatigue in multiple sclerosis: a look at the role of poor sleep | journal = Frontiers in Neurology | volume = 6 | page = 21 | year = 2015 | pmid = 25729378 | pmc = 4325921 | doi = 10.3389/fneur.2015.00021 | doi-access = free }}</ref> [[myasthenia gravis]], [[NMOSD]], [[Sjögren's syndrome]],<ref name="auto1"/> [[rheumatoid arthritis]],<ref>https://academic.oup.com/rheumatology/article/49/7/1294/1786149</ref><ref>{{Cite journal|title=Fatigue in Systemic Lupus Erythematosus and Rheumatoid Arthritis: A Comparison of Mechanisms, Measures and Management|first1=Mrinalini|last1=Dey|first2=Ioannis|last2=Parodis|first3=Elena|last3=Nikiphorou|date=January 26, 2021|journal=Journal of Clinical Medicine|volume=10|issue=16|pages=3566|doi=10.3390/jcm10163566|doi-access=free |pmid=34441861 |pmc=8396818 }}</ref> [[spondyloarthropathy]] and [[UCTD]];<ref>{{cite journal |last1=Hafiz |first1=Waleed |last2=Nori |first2=Rawad |last3=Bregasi |first3=Ariana |last4=Noamani |first4=Babak |last5=Bonilla |first5=Dennisse |last6=Lisnevskaia |first6=Larissa |last7=Silverman |first7=Earl |last8=Bookman |first8=Arthur A. M. |last9=Johnson |first9=Sindhu R. |last10=Landolt-Marticorena |first10=Carolina |last11=Wither |first11=Joan |title=Fatigue severity in anti-nuclear antibody-positive individuals does not correlate with pro-inflammatory cytokine levels or predict imminent progression to symptomatic disease |journal=Arthritis Research & Therapy |date=2019 |volume=21 |issue=1 |pages=223 |doi=10.1186/s13075-019-2013-9 |pmid=31685018 |pmc=6827224 |doi-access=free }}</ref> this population's primary concern is fatigue;<ref name="pmid31447842"/><ref>A 2015 US survey found that 98% of people with autoimmune diseases experienced fatigue, 89% said it was a "major issue", 68% said "fatigue is anything but normal. It is profound and prevents [them] from doing the simplest everyday tasks." and 59% said it was "probably the most debilitating symptom of having an AD." https://autoimmune.org/fatigue-survey-results-released/ {{Webarchive|url=https://web.archive.org/web/20230106195924/https://autoimmune.org/fatigue-survey-results-released/ |date=2023-01-06 }}</ref>
* [[blood disorders]], such as [[anemia]] and [[hemochromatosis]];{{medical citation needed|date=July 2023}}
* [[Traumatic brain injury|brain injury]];<ref>{{cite web | url=https://www.headway.org.uk/about-brain-injury/individuals/effects-of-brain-injury/fatigue/ | title=Fatigue after brain injury | access-date=2023-01-06 | archive-date=2023-01-06 | archive-url=https://web.archive.org/web/20230106185404/https://www.headway.org.uk/about-brain-injury/individuals/effects-of-brain-injury/fatigue/ | url-status=live }}</ref><ref>{{Cite web|url=https://www.bbc.com/future/article/20160817-the-daily-struggle-of-living-with-extreme-fatigue|title=The daily struggle of living with extreme fatigue|website=www.bbc.com}}</ref>
* [[cancer]], in which case it is called [[cancer fatigue]];<ref>{{cite web | url=https://www.cancerresearchuk.org/about-cancer/coping/physically/fatigue/what-is-cancer-fatigue | title=What is cancer fatigue? &#124; Coping physically &#124; Cancer Research UK | access-date=2023-01-06 | archive-date=2023-01-06 | archive-url=https://web.archive.org/web/20230106185829/https://www.cancerresearchuk.org/about-cancer/coping/physically/fatigue/what-is-cancer-fatigue | url-status=live }}</ref>
* [[Covid-19]] and [[Long COVID|long Covid]];<ref>{{cite web | url=https://www.nhs.uk/conditions/coronavirus-covid-19/long-term-effects-of-coronavirus-long-covid/ | title=Long-term effects of coronavirus (Long COVID) | date=7 January 2021 | access-date=6 January 2023 | archive-date=9 May 2021 | archive-url=https://web.archive.org/web/20210509120337/https://www.nhs.uk/conditions/coronavirus-covid-19/long-term-effects-of-coronavirus-long-covid/ | url-status=live }}</ref>
* [[developmental disorder]]s such as [[autism spectrum|autism spectrum disorder]];<ref name="Williams Gotham p.">{{citation | last1=Williams | first1=Zachary J. | last2=Gotham | first2=Katherine O. | title=Current and Lifetime Somatic Symptom Burden Among Transition-aged Autistic Young Adults | publisher=Cold Spring Harbor Laboratory | date=2021-10-03 | doi=10.1101/2021.10.02.21264461 | page=| s2cid=238252764 | url=https://www.medrxiv.org/content/medrxiv/early/2021/10/03/2021.10.02.21264461.1.full.pdf }}</ref>
* [[endocrine disease]]s or metabolic disorders: [[diabetes mellitus]], [[hypothyroidism]] and [[Addison's disease]];<ref name="Friedman">{{cite book |last1=Friedman |first1=Henry Harold |title=Problem-oriented Medical Diagnosis |date=2001 |publisher=Lippincott Williams & Wilkins |isbn=978-0-7817-2909-3 |pages=4–5 }}</ref>
* [[fibromyalgia]];{{medical citation needed|date=March 2024}}
* [[heart failure]] and [[heart attack]];<ref>{{Cite journal|url=https://pubmed.ncbi.nlm.nih.gov/20649663/|title=Fatigue after myocardial infarction: relationships with indices of emotional distress, and sociodemographic and clinical variables|first1=Pia|last1=Alsén|first2=Eva|last2=Brink|first3=Yvonne|last3=Brändström|first4=Björn W.|last4=Karlson|first5=Lars-Olof|last5=Persson|date=August 27, 2010|journal=International Journal of Nursing Practice|volume=16|issue=4|pages=326–334|via=PubMed|doi=10.1111/j.1440-172X.2010.01848.x|pmid=20649663|access-date=March 27, 2024|archive-date=March 27, 2024|archive-url=https://web.archive.org/web/20240327013934/https://pubmed.ncbi.nlm.nih.gov/20649663/|url-status=live}}</ref>
* [[HIV]];{{medical citation needed|date=March 2024}}
* [[Inborn error of metabolism|inborn errors of metabolism]] such as [[fructose malabsorption]];<ref>{{cite journal | vauthors = Whitehead WE, Palsson O, Jones KR | title = Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications? | journal = Gastroenterology | volume = 122 | issue = 4 | pages = 1140–1156 | date = April 2002 | pmid = 11910364 | doi = 10.1053/gast.2002.32392 | doi-access = free | url = https://cdr.lib.unc.edu/downloads/zs25xj11x }}</ref><ref>{{cite journal | vauthors = Gibson PR, Newnham E, Barrett JS, Shepherd SJ, Muir JG | title = Review article: fructose malabsorption and the bigger picture | journal = Alimentary Pharmacology & Therapeutics | volume = 25 | issue = 4 | pages = 349–363 | date = February 2007 | pmid = 17217453 | doi = 10.1111/j.1365-2036.2006.03186.x | s2cid = 11487905 | doi-access =  }}</ref>
* [[infectious diseases]] such as [[infectious mononucleosis]] or [[tuberculosis]];<ref name=Friedman/>
* [[irritable bowel syndrome]];{{medical citation needed|date=March 2024}}
* [[kidney disease]]s, e.g., [[acute renal failure]], [[chronic renal failure]];<ref name=Friedman />
* [[leukemia]] or [[lymphoma]];{{medical citation needed|date=March 2024}}
* [[liver failure]] or liver diseases, e.g., [[hepatitis]];<ref name=Friedman/><ref name=Swain2006/>
* [[Lyme disease]];{{medical citation needed|date=March 2024}}
* [[neurological disorder]]s such as [[narcolepsy]], [[Parkinson's disease]], [[Postural Orthostatic Tachycardia Syndrome|postural orthostatic tachycardia syndrome]] (POTS) and [[post-concussion syndrome]];{{medical citation needed|date=March 2024}}
* [[physical trauma]] and other [[pain]]-causing conditions, such as [[arthritis]];{{medical citation needed|date=March 2024}}
* [[sleep deprivation]] or [[sleep disorder]]s, e.g. [[sleep apnea]];<ref name=Friedman/>
* [[stroke]];{{medical citation needed|date=March 2024}}
* [[thyroid disease]] such as [[hypothyroidism]];{{medical citation needed|date=March 2024}}

====Substance use illnesses====
* [[substance use disorder]]s including [[alcohol use disorder]];<ref name="Avellaneda Fernández-2009">{{cite journal | vauthors = Avellaneda Fernández A, Pérez Martín A, Izquierdo Martínez M, Arruti Bustillo M, Barbado Hernández FJ, de la Cruz Labrado J, Díaz-Delgado Peñas R, Gutiérrez Rivas E, Palacín Delgado C, Rivera Redondo J, Ramón Giménez JR | display-authors = 6 | title = Chronic fatigue syndrome: aetiology, diagnosis and treatment | journal = BMC Psychiatry | volume = 9 | issue = Suppl 1 | pages = S1 | date = October 2009 | pmid = 19857242 | pmc = 2766938 | doi = 10.1186/1471-244X-9-S1-S1 | doi-access = free }}</ref>

====Mental illnesses====
* [[anxiety disorder]]s, such as [[generalized anxiety disorder]];<ref name= DSM5>{{cite book | title=Diagnostic and statistical manual of mental disorders 5th edition: [[DSM-5]] | publisher=American Psychiatric Association | publication-place=Arlington, VA Washington, D.C | year=2013 | isbn=978-0-89042-555-8 | oclc=830807378 | page= [https://archive.org/details/diagnosticstatis0005unse/page/189 189–195]}}</ref>
* [[Major depressive disorder|depression]];<ref>{{Cite web|url=https://icd.who.int/browse/2024-01/mms/en#1194756772|title=ICD-11 for Mortality and Morbidity Statistics|website=icd.who.int|access-date=2024-03-26|archive-date=2024-02-23|archive-url=https://web.archive.org/web/20240223110155/https://icd.who.int/browse/2024-01/mms/en#1194756772|url-status=live}}</ref><ref name="pmid34599320"/>
* [[eating disorder]]s, which can produce fatigue due to inadequate nutrition;{{medical citation needed|date=March 2024}}
* [[Gulf War syndrome]];{{medical citation needed|date=March 2024}}

====Other====
* [[myalgic encephalomyelitis/chronic fatigue syndrome]] (ME/CFS);<ref name="Avellaneda Fernández-2009"/>
* [[idiopathic chronic fatigue]], a term used to describe chronic fatigue which does not have symptoms of ME/CFS.<ref name="PMC6522773">{{Cite journal |last=Son |first=Chang-Gue |date=2019-06-01 |title=Differential diagnosis between "chronic fatigue" and "chronic fatigue syndrome" |journal=Integrative Medicine Research |language=en |volume=8 |issue=2 |pages=89–91 |doi=10.1016/j.imr.2019.04.005 |issn=2213-4220 |pmc=6522773 |pmid=31193269}}</ref><ref>{{Cite journal|title=Comparing Idiopathic Chronic Fatigue and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) in Males: Response to Two-Day Cardiopulmonary Exercise Testing Protocol|first1=C. (Linda) M. C.|last1=van Campen|first2=Frans C.|last2=Visser|date=June 19, 2021|journal=Healthcare|volume=9|issue=6|pages=683|doi=10.3390/healthcare9060683|doi-access=free |pmid=34198946 |pmc=8230194}}</ref> However ICF does not have a dedicated diagnostic code in the [[World Health Organization]]'s [[ICD-11]] classification.<ref>{{Cite web|title=ICD-11 - Mortality and Morbidity Statistics {{!}} MG22 Fatigue|url=https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/1109546957|date=2019|website=World Health Organization|access-date=2023-04-25|archive-date=2018-08-01|archive-url=https://archive.today/20180801205234/https://icd.who.int/browse11/l-m/en%23/http://id.who.int/icd/entity/294762853#/http://id.who.int/icd/entity/1109546957|url-status=live}}
This includes a category MG22 Fatigue (typically fatigue following exertion but sometimes may occur in the absence of such exertion as a symptom of health conditions), and many other categories where fatigue is mentioned as a secondary result of other factors.
* 8E49 Postviral fatigue syndrome
* QE84 Acute stress reaction, Combat fatigue
* 6A70-6A7Z Depressive disorders
* 07 Sleep-wake disorders
* FB32.5 Muscle strain or sprain, causing muscular fatigue
* NF01.3 Heat fatigue, transient
* MA82.Y Voice disturbances, causing voice fatigue
* BD1Z Heart failure, unspecified, causing myocardial fatigue
* JA65.Y Conditions predominantly related to pregnancy, causing fatigue which complicates pregnancy
* SD91 Fatigue consumption disorder, causing coughing, fever, diarrhea, chest pain etc.
* MG2A Ageing associated decline in intrinsic capacity, causing senile fatigue
* NF07.2 Exhaustion due to exposure
* NF01 Heat exhaustion
* 6C20 Bodily distress disorder.</ref>

==== Primary vs. secondary ====
In some areas it has been proposed that fatigue be separated into primary fatigue, caused directly by a disease process, and ordinary or secondary fatigue, caused by a range of causes including exertion and also secondary impacts on a person of having a disease (such as disrupted sleep).<ref>{{Cite web|url=https://practicalneurology.com/articles/2018-july-aug/fatigue-in-patients-with-multiple-sclerosis|title=Fatigue in Patients with Multiple Sclerosis|access-date=2021-10-18|archive-date=2022-06-16|archive-url=https://web.archive.org/web/20220616230104/https://practicalneurology.com/articles/2018-july-aug/fatigue-in-patients-with-multiple-sclerosis|url-status=live}}</ref><ref>{{cite journal | vauthors = Chalah MA, Riachi N, Ahdab R, Créange A, Lefaucheur JP, Ayache SS | title = Fatigue in Multiple Sclerosis: Neural Correlates and the Role of Non-Invasive Brain Stimulation | journal = Frontiers in Cellular Neuroscience | volume = 9 | page = 460 | year = 2015 | pmid = 26648845 | pmc = 4663273 | doi = 10.3389/fncel.2015.00460 | doi-access = free }}</ref><ref name="Gerber et al 2019">{{cite journal | vauthors = Gerber LH, Weinstein AA, Mehta R, Younossi ZM | title = Importance of fatigue and its measurement in chronic liver disease | journal = World Journal of Gastroenterology | volume = 25 | issue = 28 | pages = 3669–3683 | date = July 2019 | pmid = 31391765 | pmc = 6676553 | doi = 10.3748/wjg.v25.i28.3669 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Hartvig Honoré P |title=Fatigue |journal=European Journal of Hospital Pharmacy |date=June 2013 |volume=20 |issue=3 |pages=147–148 |doi=10.1136/ejhpharm-2013-000309 |s2cid=220171226 |doi-access=free }}</ref><ref>{{Cite journal|title=Central fatigue in multiple sclerosis: a review of the literature: The Journal of Spinal Cord Medicine: Vol 39, No 4|date=2016 |doi=10.1080/10790268.2016.1168587 |pmid=27146427 |pmc=5102292 |journal=The Journal of Spinal Cord Medicine |volume=39 |issue=4 |pages=386–399 | vauthors = Newland P, Starkweather A, Sorenson M }}</ref><ref>{{cite journal |last1=Patejdl |first1=Robert |last2=Zettl |first2=Uwe K. |title=The pathophysiology of motor fatigue and fatigability in multiple sclerosis |journal=Frontiers in Neurology |date=27 July 2022 |volume=13 |doi=10.3389/fneur.2022.891415 |doi-access=free |pmid=35968278 |pmc=9363784 }}</ref> The ICD-11 MG22 definition of fatigue<ref>{{Cite web|url=https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/1109546957|title=ICD-11 for Mortality and Morbidity Statistics|website=icd.who.int|access-date=2021-11-26|archive-date=2018-08-01|archive-url=https://archive.today/20180801205234/https://icd.who.int/browse11/l-m/en%23/http://id.who.int/icd/entity/294762853#/http://id.who.int/icd/entity/1109546957|url-status=live}}</ref> captures both types of fatigue; it includes fatigue that "occur[s] in the absence of... exertion... as a symptom of health conditions."{{medical citation needed|date=March 2024}}