Fatigue can refer to a subjective symptom of malaise and aversion to activity
or to objectively impaired performance. It hasboth physical and
mental aspects. The symptom of fatigue is apoorly defined feeling,
and careful inquiry is needed to clarifycomplaints of "fatigue,"
"tiredness," or "exhaustion" and to distinguishlack of energy from
loss of motivation or sleepiness, which maybe pointers to specific
diagnoses (see below).
Weary 1887 by Edward Radford
(1831-1920)
PrevalenceLike
blood pressure, subjective fatigue is normally distributed in the population.
The prevalence of clinicallysignificant fatigue depends on the
threshold chosen for severity(usually defined in terms of associated
disability) and persistence.Surveys report that 5-20% of the general
population suffer fromsuch persistent and troublesome fatigue.
Fatigue is twice as commonin women as in men but is not strongly
associated with age oroccupation. It is one of the commonest
presenting symptoms inprimary care, being the main complaint of
5-10% of patients andan important subsidiary symptom in a further
5-10%.
Fatigue as a symptomPatients
generally regard fatigue as important (because it is disabling), whereas doctors
do not (becauseit is diagnostically non-specific). This discrepancy
is a potentsource of potential difficulty in the doctor-patient
relationship.Fatigue may present in association with established
medical andpsychiatric conditions or be idiopathic. Irrespective of
cause,it has a major impact on day to day functioning and quality oflife. Without treatment, the prognosis of patients with idiopathicfatigue is surprisingly poor; half those seen in general practicewith fatigue are still fatigued six months later.
The physiological and psychological mechanisms underlying subjective fatigue
are poorly understood. Fatigue may rather beusefully regarded as a
final common pathway for a variety of causalfactors. These can be
split into predisposing, precipitating,and perpetuating
factors.
Predisposing factors include being female and a history of either
fatigue ordepression.
Precipitating factors include acute physical stresses such as
infection with Epstein-Barr virus, psychological stresses suchas
bereavement, and social stresses such as work problems.
Medical conditions
that may present with apparently unexplained fatigue
GeneralAnaemia,
chronic infection, autoimmune disease, cancer
Sleep disordersObstructive
sleep apnoea and other sleep disorders
NeuromuscularMyositis,
multiple sclerosis
GastrointestinalLiver
disease
CardiovascularChronic
heart disease
RespiratoryChronic
lung disease
Perpetuating factors include physical inactivity, emotional disorders,
ongoing psychological or social stresses, and abnormalitiesof sleep.
These factors should be sought as part of the clinicalassessment.
Other physiological factors such as immunological abnormalities and slightly
low cortisol concentration are of research interestbut not clinicalvalue.
Diagnoses associated with fatigue
Among patients who present with severe chronicfatigue as their main
complaint, only a small proportion willbe suffering from a
recognised medical disease. In no more than10% of patients
presenting with fatigue in primary care is a diseasecause found. The
rate is even lower in patients seen in secondarycare.
Fatigue is a major symptom of many psychiatric disorders, but for a
substantial proportion of patients with fatigue the symptomremains
unexplained or idiopathic. In general, the more severethe fatigue
and the larger the number of associated somatic (andunexplained)
complaints, then the greater the disability and thegreater the
likelihood of a diagnosis of depression.
Psychiatric diagnoses
commonly associated with fatigue
Depression
Anxiety and panic
Eating disorders
Substance misuse disorders
Somatisation disorder
Chronic fatigue syndromes
Chronic fatigue syndrome is a useful descriptiveterm for prominent
physical and mental fatigue with muscular painand other symptoms. It
overlaps with another descriptive term,fibromyalgia, that has often
been used when muscle pain is predominantbut in which fatigue is
almost universal. There is also substantialoverlap of the diagnoses
with other symptom based syndromes, theso called functional somatic
syndromes.
Diagnostic criteria
for chronic fatigue syndrome
Inclusion criteria
Clinically evaluated, medically unexplained fatigue of at least
6 months' duration that is
Of new onset (not life long)
Not result of ongoing exertion
Not substantially alleviated by rest
Associated with a substantial reduction in previous level of activities
Occurrence of 4 or more of the following symptoms
Subjective memory impairment, sore throat, tender lymph nodes, muscle
pain, joint pain, headache, unrefreshing sleep, post-exertional malaise
lasting more than 24 hours
Exclusion criteria
Active, unresolved, or suspected medical disease or psychotic,
melancholic, or bipolar depression (but not uncomplicated major
depression), psychotic disorders, dementia, anorexia or bulimia nervosa,
alcohol or other substance misuse, severe obesity
The term myalgic encephalomyelitis (or encephalopathy) has been used in
Britain and elsewhere to describe a poorly understoodillness in
which a prominent symptom is chronic fatigue exacerbatedby activity.
This is a controversial diagnosis that some regardas simply another
name for chronic fatigue syndrome and that othersregard as a
distinct condition. This article will focus on chronicfatiguesyndrome.
Prevalence and outcomeChronic
fatigue syndrome can be diagnosed in up to 2% of primary care patients.
Untreated, the prognosisis poor, with only about 10% of patients
recovering in a two tofour years. A preoccupation with medical
causes seems to be anegative prognosticfactor.
HistoryThe
nature of the fatigue is an important clue to diagnosis, and it is therefore
important to clarify patients' complaints.Fatigue described as loss
of interest and enjoyment (anhedonia)points to depression. Prominent
sleepiness suggests a sleep disorder.The history should also cover
Screening tests for
fatigue
Full blood count
Erythrocyte sedimentation rate or C reactive protein
Liver function tests
Urea and electrolytes
Thyroid stimulating hormone and thyroid function tests
Creatine kinase
Urine and blood tests for glucose
Urine test for protein
Systematic inquiry for diseases often associated with fatigue
Symptoms of depression anxiety and sleep disorder
Patients' own understanding of their illness and how they cope with it
Current socialstresses.
ExaminationBoth
a physical and mental state examination must be performed in every case, to seek
medical and psychiatricdiagnoses associated withfatigue.
Routine investigationsIf
there are no specific indications for special investigations, a standard set of
screening testsisadequate.
Special investigationsImmunological
and virological tests are generally unhelpful as routine investigations. Sleep
studiescan be useful in excluding other diagnoses, especially
obstructivesleep apnoea and narcolepsy.
Factors to consider in
a formulation of chronic fatigue
Predisposing cause
Precipitating cause
Perpetuating cause
Biological
Biological vulnerability
Acute disease
PathophysiologyExcessive inactivitySleep disorder
Psychological
Vulnerable personality
Stress
DepressionUnhelpful beliefs about causeFearful
avoidance of activity
Social
Lack of support
Life eventsSocial or work stress
Reinforcement of unhelpful beliefsSocial or work stress
Psychological assessmentIt
is important to inquire fully about patients' understanding of their illness
(questions may include"What do you think is wrong with you?" and
"What do you thinkthe cause is?"). Patients may be worried that the
fatigue is asymptom of a severe, as yet undiagnosed, disease or that
activitywill cause a long term worsening of their
condition.
FormulationA
formulation that distinguishes predisposing, precipitating, and multiple
perpetuating factors is valuable inproviding an explanation to
patients and for targetingintervention.
Persistent fatigue requires active management, preferably before it has
become chronic. When a specific disease cause of fatiguecan be
identified this should be treated. If no disease diagnosiscan be
made, or if medical treatment of disease fails to relievethe
fatigue, a broader biopsychosocial management strategy isrequired. A
discussion with the patient about fatigue and itstreatment can be
supplemented with written material (see below).
Management of chronic
fatigue
1 Assessment
Empathise
History
Examination
Limited investigation
Biopsychosocial formulations
2 Treat treatable medical and psychiatric conditions
3 Help patient to overcome perpetuating factors
Educate
Reduce distress
Gradual increase in activity
Solve social and occupational problems
4 Follow up
Patients should be told that they are suffering from a common and treatable
condition that the doctor takes seriously andfor which behavioural
treatment can be helpful. While patientsmay be concerned about
possible disease and the need for medicalinvestigation and
treatment, it can be explained that no diseasehas been found, and
hence there is no disease based treatment,but that with help there
is a great deal that the patients candothemselves.
Identifying unhelpful beliefsPotentially
unhelpful beliefs should be discussed. If a patient has a simple aetiological
model(such as "It is all due to a virus") an alternative approach
basedon a biopsychosocial formulation can be outlined. This has theadvantage of highlighting potential perpetuating factors, as thesemay be regarded as obstacles to recovery. Doctor and patient canthen work together to overcome these. It is rarely productive
to argue over the best name for the illness; instead, the emphasis
should be on agreeing a positive and open minded approach to rehabilitation.
Patients should be encouraged to gradually
increase their activity. ("Mrs Bradbury's establishment for the recovery
of ladies nervously affected," from On insanity by William B
Neville London 1836)
Managing activity and avoidanceGradual
increases in activity can be advised unless there is a clear contraindication.
Itis critical, however, to distinguish between carefully gradedincreases carried out in collaboration with patients and "forced"exercise. It is also important to explain that erratic variationbetween overactivity on "good" days and subsequent collapse doesnot help long term recovery and that "stabilising" activity is
a prerequisite to graded increases.
Efficacy of cognitive behaviour therapy
for treating chronic fatigue syndrome
Depression and anxietyIf
there is evidence of depression a trial of an antidepressant drug is worth
while. Patients withfatigue are often sensitive to the side effects
of antidepressants.However, if they are given adequate information
about what toexpect when treatment begins, with small doses, most
patientscan tolerate them. Randomised trials have shown
psychologicaltherapies such as cognitive behaviour therapy to be
equally effectivefor mild to moderatedepression.
Managing occupational and social stressesPatients
who remain in work may be overstressed by it. Those who have left workmay be inactive and demoralised and may not wish to return to
the same job. These situations require a problem solving approachto
consider how to manage work demands, achieve a return to work,or to
plan an alternativecareer.
Most patients with fatigue are managed in primary care, but certain groups
may require referral to specialist care:
Children with chronic fatigue
Patients in whom the general practitioner suspects occult disease
Patients with severe psychiatric illness
Patients requiring specialist management of sleep disorders
Patients unresponsive to management in primarycare.
Referral may be to a physician or psychiatrist as is deemed most appropriate.
Psychologists may be able to offer cognitivebehaviour therapy. Where
available, joint medical and psychiatricclinics are ideally suited
to the assessment of chronic fatigueand related problems. It is
essential there is close liaison betweenprimary and specialist care
to ensure a clear, consistent, andencouraging approach by all
concerned.
What is cognitive
behaviour therapy?
Brief pragmatic psychological therapy
Targets beliefs and behaviours that might perpetuate symptoms
An established treatment for depression and anxiety
Has been adapted for somatic complaints of pain and fatigue
Requires a skilled therapist
Rehabilitation
Rehabilitation based on behavioural principlesis currently the most
effective specialist treatment approach.
What is graded
exercise therapy?
Explanation of fatigue as a physiological consequence of inactivity,
poor sleep, and disturbed circadian rhythms
Discussion, agreement, and implementation of graded exercise plans
Monitoring of progress and setting of appropriate new targets
Cognitive behaviour therapy is a collaborative psychological
rehabilitation that incorporates graded increases in activitybut
also pays greater attention to patients' beliefs andconcerns.
Graded exercise therapy is a structured progressive exercise programme
administered and carefully monitored by a therapist.
Evidence based summary
Chronic fatigue syndrome is a descriptive term for a disabling
syndrome that probably has multiple causes (physical and psychological)
Graded exercise and cognitive behaviour therapies are effective in
treating chronic fatigue syndrome
Wessely S. Chronic fatigue: symptom and syndrome. Ann Intern Med
2001;134:838-43
Whiting P, Bagnall AM, Sowden AJ, Cornell JE, Mulrow CD, Ramirez
G. Interventions for the treatment and management of chronic fatigue
syndrome: a systematic review. JAMA 2001;286:1360-8
Both may be used in conjunction with antidepressant drugs. Both have been
found to be effective in randomised trials of hospitalreferred cases
of chronic fatigue syndrome. Some general practitionersare able to
provide graded exercise or cognitive behaviour therapyin their
practice or clinic. Others may wish to refer to a trainedtherapist.
Fatigue is a ubiquitous symptom that is important to patients and has a major
impact on their quality of life. It remainspoorly understood and has
hitherto probably been not been givenadequate attention by doctors.
Early and active management offatigue in primary care may prevent
progression to chronicity.Patients who have developed a chronic
fatigue syndrome can benefitfrom specific treatments. Paying more
attention to the symptomof fatigue may help to avoid the distress
and poor outcome thatis associated with patients feeling that their
problems are neitheraccepted nor understood. It may also reduce the
numbers who turnto a variety of unproved, and even harmful,
alternative approaches.
Further reading
Wessely S, Hotopf M, Sharpe M. Chronic fatigue and its syndromes.
Oxford: Oxford University Press, 1998
Campling F, Sharpe M. Chronic fatigue syndrome: the facts.
Oxford: Oxford University Press, 2000
Reid S, Chalder T, Cleare A, Hotopf M, Wessely S. Chronic fatigue
syndrome. Clinical Evidence 2001 (Nov)
Acknowledgments
The painting Weary is held at Russell-Cotes Art Gallery and Museum,
Bournemouth, and is reproduced with permission of BridgemanArt
Library. The graph of distribution of fatigue in the populationis
adapted from Pawlikowska T, et al BMJ 1994;308:763-6. The box
of diagnostic criteria for chronic fatigue syndrome is adaptedfrom
Fukuda K, et al Ann Intern Med 1994;121:953-9. The printof "Mrs
Bradbury's establishment for the recovery of ladies nervously
affected" is reproduced with permission of Wellcome Library. The
graph showing efficacy of cognitive behaviour therapy is adaptedfrom
Prins JB, et al Lancet 2001;357:841-7.
Footnotes
Michael Sharpe is reader in psychological medicine, University of Edinburgh.
David Wilks is consultant in infectious diseases,Western General
Hospital,Edinburgh.
The ABC of psychological medicine is edited by Richard Mayou, professor of
psychiatry, University of Oxford; Michael Sharpe;and Alan Carson,
consultant neuropsychiatrist, NHS Lothian, andhonorary senior
lecturer, University of Edinburgh. The serieswill be published as a
book in winter2002.
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