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Fatigue

ICD-10	R53.
ICD-9	780.7
DiseasesDB	30079
MedlinePlus	003088
MeSH	D005221

Fatigue (also called exhaustion, lethargy, languidness, languor, lassitude, and listlessness) is a weariness caused by exertion. It can describe a range of afflictions, varying from a general state of lethargy to a specific work-induced burning sensation within one's muscles. It can be both physical and mental. Physical fatigue is the inability to continue functioning at the level of one's normal abilities.¹²³ It is ubiquitous in everyday life, but usually becomes particularly noticeable during heavy exercise. Mental fatigue, on the other hand, rather manifests in somnolence.

Fatigue is considered a symptom, as opposed to a medical sign, because it is reported by the patient instead of being observed by others.

Contents 1 Types 1.1 Physical fatigue 1.2 Mental fatigue 2 Causes 2.1 Diseases and conditions 2.2 Medications 3 See also 4 Notes 5 References 6 External links

Types

Physical fatigue

Main article: Muscle weakness

Physical fatigue or muscle weakness (or "lack of strength") is a direct term for the inability to exert force with one's muscles to the degree that would be expected given the individual's general physical fitness. A test of strength is often used during a diagnosis of a muscular disorder before the etiology can be identified. Such etiology depends on the type of muscle weakness, which can be true or perceived as well as central or peripheral. True weakness is substantial, while perceived rather is a sensation of having to put more effort to do the same task. On the other hand, central muscle weakness is an overall exhaustion of the whole body, while peripheral weakness is an exhaustion of individual muscles.

Mental fatigue

See also: Somnolence

In addition to physical, fatigue also includes mental fatigue, not necessarily including any muscle fatigue. Such a mental fatigue, in turn, can manifest itself both as somnolence (decreased wakefulness) or just as a general decrease of attention, not necessarily including sleepiness. In any case, this can be dangerous when performing tasks that require constant concentration, such as driving a vehicle. For instance, a person who is sufficiently somnolent may experience microsleeps. However, objective cognitive testing should be done to differentiate the neurocognitive deficits of brain disease from those attributable to tiredness.

Causes

Fatigue is typically the result of working, mental stress, over stimulation and under stimulation, jet lag or active recreation, depression, and also boredom, disease and lack of sleep. It may also have chemical causes, such as poisoning or mineral or vitamin deficiencies. Massive blood loss, resulting in anemia, frequently results in fatigue.

The sense of fatigue is believed to originate in the reticular activating system of the lower brain. Musculoskeletal structures may have co-evolved with appropriate brain structures so that the complete unit functions together in a constructive and adaptive fashion.⁴ The entire systems of muscles, joints, and proprioceptive and kinesthetic functions plus parts of the brain evolve and function together in a unitary way.⁵

Diseases and conditions

Temporary fatigue is likely to be a minor illness like the common cold. Chronic fatigue, on the other hand, meaning of six months or more duration, is a symptom of a large number of different diseases or conditions.

• Autoimmune diseases such as celiac disease and spondyloarthropathy
• Anxiety or panic disorder
• Blood disorders such as anemia and hemochromatosis
• Cancer
• Chemical dependency
• Chronic fatigue syndrome (CFS)
• Depression and other mental disorders that feature depressed mood
• Diabetes
• Eating disorders
• Fibromyalgia
• Heart disease
• Hypothyroidism
• Infectious diseases such as infectious mononucleosis, Lyme disease
• Lead poisoning
• Leukemia or lymphoma
• Muscular dystrophy
• Physical trauma and other pain-causing conditions, such as arthritis
• Neurological disorders such as Parkinson's disease and post-concussion syndrome
• Pregnancy
• Sleep deprivation or sleep disorders
• Superior canal dehiscence syndrome
• Wilson's disease

Medications

• Certain medications, e.g. lithium salts, ciprofloxacin
• Beta blocker medication causes fatigue, especially after exertion, inducing exercise intolerance.⁶
• Many cancer treatments cause fatigue, particularly chemotherapy and radiotherapy

See also

Other fatigue-related articles

• Fatigue (safety)
• Sleep deprived driving
• Combat stress reaction (Battle fatigue)

Other medical symptoms and conditions

• Malaise
• Asthenia
• Paresis
• Debility
• Muscle fatigue
• Eye circles

Notes

References

• Gandevia SC (1992). "Some central and peripheral factors affecting human motoneuronal output in neuromuscular fatigue". Sports medicine (Auckland, N.Z.) 13 (2): 93–8. PMID 1561512.
• Hagberg M (1981). "Muscular endurance and surface electromyogram in isometric and dynamic exercise". Journal of applied physiology: respiratory, environmental and exercise physiology. 51 (1): 1–7. PMID 7263402.
• Hawley JA, Reilly T (1997). "Fatigue revisited". Journal of sports sciences. 15 (3): 245–6. PMID 9232549.
• Edelman, Gerald Maurice (1989). The remembered present: a biological theory of consciousness. New York: Basic Books. ISBN 0-465-06910-X.
• Kelso, J. A. Scott (1995). Dynamic patterns: the self-organization of brain and behavior. Cambridge, Mass: MIT Press. ISBN 0-262-61131-7.

External links

• Fatigue -- Information for Patients, U.S. National Cancer Institute

v • d • e Symptoms and signs: general (R50-R69, 780-789) Fever Hyperpyrexia - Fever of unknown origin Pain Headache - Chronic pain Malaise/Fatigue Asthenia - Debility Fainting/syncope Vasovagal syncope - Carotid sinus syncope - Heat syncope Ingestion food and fluid intake (Anorexia, Polydipsia, Polyphagia) - Cachexia - Xerostomia Anorexia/Weight loss Hemodynamic Shock: Cardiogenic - Hypovolemic - Distributive (Septic, Neurogenic) Edema: Peripheral edema - Anasarca Hyperaemia: Functional - Reactive Lymphadenopathy Underdevelopment Delayed milestone - Failure to thrive - Short stature (Idiopathic) Other Seizure (Febrile seizure) Hyperhidrosis (Sleep hyperhidrosis) Clubbing - Tenderness

v • d • e Common cold Viruses Rhinovirus - Coronavirus - Human parainfluenza viruses - Human respiratory syncytial virus - Adenovirus - Enterovirus - Metapneumovirus Symptoms Pharyngitis - Rhinorrhea - Nasal congestion - Sneezing - Cough - Muscle aches - Fatigue - Malaise - Headache - Weakness - Loss of appetite Complications Acute bronchitis - Bronchiolitis - Croup - Pneumonia - Sinusitis - Otitis media - Strep throat Antiviral drugs Pleconaril (experimental)

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• This page was last modified on 23 November 2008, at 00:35.

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