Fatigue

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Fatigue
Other namesExhaustion, weariness, tiredness, lethargy, languidness, languor, lassitude, listlessness, injuries
Moods, Ambassador William Foster, Under Secretary of State George Ball, President Lyndon B. Johnson, Secretary of... - NARA - 192609.tif
Long meetings can often be a source of exhaustion, as evidenced by Lyndon B. Johnson in this photograph.
Specialty Internal medicine, Family practice, Psychiatry, Psychology

Fatigue is a feeling of tiredness. [1] It may be sudden or gradual in onset. It is a normal phenomenon if it follows prolonged physical or mental activity, and resolves completely with rest. However, it may be a symptom of a medical condition if it is prolonged, severe, progressive, or occurs without provocation.

Contents

Physical fatigue is the transient inability of muscles to maintain optimal physical performance, and is made more severe by intense physical exercise. [2] [3] [4] Mental fatigue is a transient decrease in maximal cognitive performance resulting from prolonged periods of cognitive activity. Mental fatigue can manifest as somnolence, lethargy, or directed attention fatigue. [5]

Fatigue and 'feelings of fatigue' are sometimes confused. [6] Unlike weakness, fatigue can usually be alleviated by periods of rest.

Classification

Physical fatigue

Physical fatigue, or muscle fatigue, is the temporary physical inability of muscles to perform optimally. The onset of muscle fatigue during physical activity is gradual, and depends upon an individual's level of physical fitness – other factors include sleep deprivation and overall health. Fatigue can be reversed by rest. [7] Physical fatigue can be caused by a lack of energy in the muscle, by a decrease of the efficiency of the neuromuscular junction or by a reduction of the drive originating from the central nervous system. [8] The central component of fatigue is triggered by an increase of the level of serotonin in the central nervous system. [9] During motor activity, serotonin released in synapses that contact motoneurons promotes muscle contraction. [10] During high level of motor activity, the amount of serotonin released increases and a spillover occurs. Serotonin binds to extrasynaptic receptors located on the axon initial segment of motoneurons with the result that nerve impulse initiation and thereby muscle contraction are inhibited. [11]

Muscle strength testing can be used to determine the presence of a neuromuscular disease, but cannot determine its cause. Additional testing, such as electromyography, can provide diagnostic information, but information gained from muscle strength testing alone is not enough to diagnose most neuromuscular disorders. [12]

People with multiple sclerosis experience a form of overwhelming lassitude or tiredness that can occur at any time of the day, for any duration, and that does not necessarily recur in a recognizable pattern for any given patient, referred to as "neurological fatigue". [13] [14]

Mental fatigue

Mental fatigue is a temporary inability to maintain optimal cognitive performance. The onset of mental fatigue during any cognitive activity is gradual, and depends upon an individual's cognitive ability, and also upon other factors, such as sleep deprivation and overall health. Mental fatigue has also been shown to decrease physical performance. [5] It can manifest as somnolence, lethargy, directed attention fatigue, or disengagement. Research also suggests that mental fatigue is closely linked to the concept of ego depletion. For example, one pre-registered study of 686 participants found that after exerting mental effort, people are likely to disengage and become less interested in exerting further effort. [15] Decreased attention can also be described as a more or less decreased level of consciousness. [16] In any case, this can be dangerous when performing tasks that require constant concentration, such as operating large vehicles. For instance, a person who is sufficiently somnolent may experience microsleep. However, objective cognitive testing can be used to differentiate the neurocognitive deficits of brain disease from those attributable to tiredness.[ citation needed ]

The perception of mental fatigue is believed to be modulated by the brain's reticular activating system (RAS).[ citation needed ]

Fatigue impacts a driver's reaction time, awareness of hazards around them and their attention. Drowsy drivers are three times more likely to be involved in a car crash and if they are awake over 20 hours, is the equivalent of driving with a blood-alcohol concentration level of 0.08%. [17]

Causes

Normal

Fatigue is a normal result of working, mental stress, overstimulation and understimulation, jet lag, active recreation, boredom, and lack of sleep.

Multiple Sclerosis fatigue may include primary fatigue caused by processes of the disease, such as demyelination. [18] [19] [20]

Acute

Causes of acute fatigue include depression; chemical causes, such as dehydration, poisoning, low blood sugar, or mineral or vitamin deficiencies. Fatigue is different from drowsiness, where a patient feels that sleep is required.[ citation needed ]

Temporary fatigue is likely to be a minor illness like the common cold as one part of the sickness behavior response that happens when the immune system fights an infection.

Prolonged

Prolonged fatigue is a self-reported, persistent (constant) fatigue lasting at least one month.

Chronic

Chronic fatigue is a self-reported fatigue lasting at least six consecutive months. Chronic fatigue may be either persistent or relapsing. [21] Chronic fatigue is a symptom of many diseases and conditions. Some major categories of conditions that feature fatigue include:

Fatigue may also be a side effect of certain medications (e.g., lithium salts, ciprofloxacin); beta blockers, which can induce exercise intolerance; and many cancer treatments, particularly chemotherapy and radiotherapy.

Inflammation

Inflammation has been linked to many types of fatigue. [22] Findings implicate neuroinflammation in the etiology of fatigue in autoimmune and related disorders. [22]

Diagnosis

Minor dark circles, in addition to a hint of eye bags, a combination which is suggestive of sleep deprivation and/or mental fatigue. Dark circles (cropped).png
Minor dark circles, in addition to a hint of eye bags, a combination which is suggestive of sleep deprivation and/or mental fatigue.

One study concluded about 50% of people who have fatigue receive a diagnosis that could explain the fatigue after a year with the condition. In those people who have a possible diagnosis, musculoskeletal (19.4%) and psychological problems (16.5%) are the most common. Definitive physical conditions were only found in 8.2% of cases. [29]

If a person with fatigue decides to seek medical advice, the overall goal is to identify and rule out any treatable conditions. This is done by considering the person's medical history, any other symptoms that are present, and evaluating of the qualities of the fatigue itself. The affected person may be able to identify patterns to the fatigue, such as being more tired at certain times of day, whether fatigue increases throughout the day, and whether fatigue is reduced after taking a nap.

Because disrupted sleep is a significant contributor to fatigue, a diagnostic evaluation considers the quality of sleep, the emotional state of the person, sleep pattern, and stress level. The amount of sleep, the hours that are set aside for sleep, and the number of times that a person awakens during the night are important. A sleep study may be ordered to rule out a sleep disorder.

Depression and other psychological conditions can produce fatigue, so people who report fatigue are routinely screened for these conditions, along with substance use disorders, poor diet, and lack of physical exercise, which paradoxically increases fatigue.

Basic medical tests may be performed to rule out common causes of fatigue. These include blood tests to check for infection or anemia, a urinalysis to look for signs of liver disease or diabetes mellitus, and other tests to check for kidney and liver function, such as a comprehensive metabolic panel. [30] Other tests may be chosen depending on the patient's social history, such as an HIV test or pregnancy test.

Comparison with sleepiness

Fatigue is generally considered a more long-term condition than sleepiness (somnolence). [31] Although sleepiness can be a symptom of a medical condition, it usually results from lack of restful sleep, or a lack of stimulation. [32] Chronic fatigue, on the other hand, is a symptom of a greater medical problem in most cases. It manifests in mental or physical weariness and inability to complete tasks at normal performance. [33] Both are often used interchangeably and even categorized under the description of 'being tired.' Fatigue is often described as an uncomfortable tiredness, whereas sleepiness is comfortable and inviting.

Measurement

Fatigue can be quantitatively measured. Devices to measure medical fatigue have been developed by Japanese companies, among them Nintendo (cancelled). [34] Nevertheless, such devices are not in common use outside Japan.

See also

Related Research Articles

Neuromyotonia (NMT) is a form of peripheral nerve hyperexcitability that causes spontaneous muscular activity resulting from repetitive motor unit action potentials of peripheral origin. NMT along with Morvan's syndrome are the most severe types in the Peripheral Nerve Hyperexciteability spectrum. Example of two more common and less severe syndromes in the spectrum are Cramp Fasciculation Syndrome and Benign Fasciculation Syndrome. NMT can have both hereditary and acquired forms. The prevalence of NMT is unknown.

Myalgia is the medical term for muscle pain. Myalgia is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another likely cause is viral infection, especially when there has been no trauma.

Fibromyalgia Chronic pain of unknown cause

Fibromyalgia (FM) is a medical condition characterized by chronic widespread pain and a heightened pain response to pressure. Other symptoms include tiredness to a degree that normal activities are affected, sleep problems, and cognitive dysfunctions. Some people also report restless legs syndrome, bowel or bladder problems, numbness and tingling and sensitivity to noise, lights or temperature. Patients with fibromyalgia are more likely to suffer from depression, anxiety and posttraumatic stress disorder.

Post-polio syndrome Human disease

Post-polio syndrome is a group of latent symptoms of poliomyelitis (polio), occurring at about a 25–40% rate. These symptoms are caused by the damaging effects of the viral infection on the nervous system. Symptoms typically occur 15 to 30 years after an initial acute paralytic attack. Symptoms include decreasing muscular function or acute weakness with pain and fatigue. The same symptoms may also occur years after a nonparalytic polio (NPP) infection.

Encephalopathy means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome has many possible organic and inorganic causes.

Somnolence is a state of strong desire for sleep, or sleeping for unusually long periods. It has distinct meanings and causes. It can refer to the usual state preceding falling asleep, the condition of being in a drowsy state due to circadian rhythm disorders, or a symptom of other health problems. It can be accompanied by lethargy, weakness, and lack of mental agility.

Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes and can cause distress and problems with functioning. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders.

Exercise intolerance Medical condition

Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe post-exercise pain, fatigue, nausea, vomiting or other negative effects. Exercise intolerance is not a disease or syndrome in and of itself, but can result from various disorders.

Obstructive sleep apnea Obstruction of the upper airway during sleep

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episodes are termed "apneas" with complete or near-complete cessation of breathing, or "hypopneas" when the reduction in breathing is partial. In either case, a fall in blood oxygen saturation, a disruption in sleep, or both may result. A high frequency of apneas or hypopneas during sleep may interfere with restorative sleep, which—in combination with disturbances in blood oxygenation—is thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime.

Muscle weakness is a lack of muscle strength. Its causes are many and can be divided into conditions that have either true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in neuromuscular junction disorders, such as myasthenia gravis. Muscle weakness can also be caused by low levels of potassium and other electrolytes within muscle cells. It can be temporary or long-lasting. The term myasthenia is from my- from Greek μυο meaning "muscle" + -asthenia ἀσθένεια meaning "weakness".

Kleine–Levin syndrome (KLS) is a rare disorder characterized by persistent episodic hypersomnia and cognitive or mood changes. Many patients also experience hyperphagia, hypersexuality and other symptoms. Patients generally experience recurrent episodes of the condition for more than a decade and may return at a later age. Individual episodes generally last more than a week, sometimes lasting for months. The condition greatly affects the personal, professional, and social lives of sufferers. The severity of symptoms and the course of the syndrome vary between sufferers. Patients commonly have about 20 episodes over about a decade. Several months generally elapse between episodes.

Organic brain syndrome Disorder of mental function whose cause is alleged to be known as physiological

Organic brain syndrome, also known as organic brain disease, organic brain disorder, organic mental syndrome, or organic mental disorder, refers to any syndrome or disorder of mental function whose cause is alleged to be known as organic (physiologic) rather than purely of the mind. These names are older and nearly obsolete general terms from psychiatry, referring to many physical disorders that cause impaired mental function. They are meant to exclude psychiatric disorders. Originally, the term was created to distinguish physical causes of mental impairment from psychiatric disorders, but during the era when this distinction was drawn, not enough was known about brain science for this cause-based classification to be more than educated guesswork labeled with misplaced certainty, which is why it has been deemphasized in current medicine. While mental or behavioural abnormalities related to the dysfunction can be permanent, treating the disease early may prevent permanent damage in addition to fully restoring mental functions. An organic cause to brain dysfunction is suspected when there is no indication of a clearly defined psychiatric or "inorganic" cause, such as a mood disorder.

Medically unexplained physical symptoms are symptoms for which a treating physician or other healthcare providers have found no medical cause, or whose cause remains contested. In its strictest sense, the term simply means that the cause for the symptoms is unknown or disputed—there is no scientific consensus. Not all medically unexplained symptoms are influenced by identifiable psychological factors. However, in practice, most physicians and authors who use the term consider that the symptoms most likely arise from psychological causes. Typically, the possibility that MUPS are caused by prescription drugs or other drugs is ignored. It is estimated that between 15% and 30% of all primary care consultations are for medically unexplained symptoms. A large Canadian community survey revealed that the most common medically unexplained symptoms are musculoskeletal pain, ear, nose, and throat symptoms, abdominal pain and gastrointestinal symptoms, fatigue, and dizziness. The term MUPS can also be used to refer to syndromes whose etiology remains contested, including chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity and Gulf War illness.

A functional symptom is a medical symptom with no known physical cause. In other words, there is no structural or pathologically defined disease to explain the symptom. The use of the term 'functional symptom' does not assume psychogenesis, only that the body is not functioning as expected. Functional symptoms are increasingly viewed within a framework in which 'biological, psychological, interpersonal and healthcare factors' should all be considered to be relevant for determining the aetiology and treatment plans.

Multiple sclerosis signs and symptoms

Multiple sclerosis can cause a variety of symptoms: changes in sensation (hypoesthesia), muscle weakness, abnormal muscle spasms, or difficulty moving; difficulties with coordination and balance; problems in speech (dysarthria) or swallowing (dysphagia), visual problems, fatigue and acute or chronic pain syndromes, bladder and bowel difficulties, cognitive impairment, or emotional symptomatology. The main clinical measure in progression of the disability and severity of the symptoms is the Expanded Disability Status Scale or EDSS.

The clinical descriptions of chronic fatigue syndrome (CFS) vary. Different agencies and scientific bodies have produced different guidelines to define the condition, with some overlap of symptoms between descriptions. Aspects of the condition are controversial, with disagreements over etiology, pathophysiology, treatment and naming between medical practitioners, researchers, patients and advocacy groups. Subgroup analysis suggests that, depending on the applied definition, the CFS population may represent a variety of conditions rather than a single disease entity.

Sundowning, or sundown syndrome, is a neurological phenomenon associated with increased confusion and restlessness in people with delirium or some form of dementia. It is most commonly associated with Alzheimer's disease but also found in those with other forms of dementia. The term "sundowning" was coined by Louis K. Evans in 1987 due to the timing of the person's increased confusion beginning in the late afternoon and early evening. For people with sundown syndrome, a multitude of behavioral problems begin to occur and are associated with long term adverse outcomes. Sundowning seems to occur more frequently during the middle stages of Alzheimer's disease and mixed dementia and seems to subside with the progression of the person's dementia. People are generally able to understand that this behavioral pattern is abnormal. Research shows that 20–45% of people with Alzheimer's will experience some variation of sundowning confusion. However, despite lack of an official diagnosis of sundown syndrome in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), there is currently a wide range of reported prevalence.

Differential diagnoses of depression Differential diagnoses

Depression, one of the most commonly diagnosed psychiatric disorders, is being diagnosed in increasing numbers in various segments of the population worldwide. Depression in the United States alone affects 17.6 million Americans each year or 1 in 6 people. Depressed patients are at increased risk of type 2 diabetes, cardiovascular disease and suicide. Within the next twenty years depression is expected to become the second leading cause of disability worldwide and the leading cause in high-income nations, including the United States. In approximately 75% of completed suicides, the individuals had seen a physician within the prior year before their death, 45–66% within the prior month. About a third of those who completed suicide had contact with mental health services in the prior year, a fifth within the preceding month.

Cancer-related fatigue is a symptom of fatigue that is experienced by nearly all cancer patients.

Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) and ME/CFS, is a complex, fatiguing, long-term medical condition diagnosed by required primary symptoms and criteria, and often involves a broad range of symptoms. Distinguishing core symptoms are lengthy exacerbations or "flares" of the illness after ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to accomplish tasks that were routine before the illness; and sleep disturbances. Orthostatic intolerance and cognitive dysfunction are also diagnostic. Other common symptoms may involve numerous body systems, and chronic pain is common.

References

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Further reading

Byung-Chul Han: Müdigkeitsgesellschaft. Matthes & Seitz, Berlin 2010, ISBN   978-3-88221-616-5. (Philosophical essay about fatigue as a sociological problem and symptom).

Classification
D
External resources