BMJ Learning

Chronic fatigue syndrome: diagnosis and management

د. حسين محمد جمعة
اختصاصي الامراض الباطنة
البورد العربي
كلية طب الموصل
2010

Chronic fatigue syndrome

is also called a lot of other names, such
as myalgic encephalomyelitis or myalgic encephalopathy(ME). It’s
defined by the NICE, as disabling fatigue without another cause.

There are two widely used definitions for chronic fatigue syndrome, one from the US Centers for Disease Control and Prevention and one from Oxford, UK. Both definitions were developed as operational criteria for research (see table 1).
There are important differences between these definitions. The UK definition insists on the presence of mental fatigue, whereas the US definition includes a requirement for several physical symptoms, reflecting the belief that chronic fatigue syndrome has an underlying immunological or infective pathology.

Weight loss is not common in chronic fatigue syndrome at all. Most people their weight is steady or they gain
weight. the core pattern here is intense physical and mental fatigue and
physical and mental fatiguability.


In adults the disabling fatigue must last at least four months or must
have been present for four months and in children it’s three months.
And there are a variety of symptoms which are usually present and
NICE suggests that at least one symptom must be present before a GP can make a diagnosis.

The symptoms

include problems with memory and concentration,
unrefreshing sleep, headaches, nausea,
muscle aches and pains, joint aches and pains.

Unexplained chronic fatigue and chronic fatigue syndrome are common conditions in primary care
Standard clinical and laboratory investigation is adequate for most patients presenting with chronic fatigue in primary care
The prognosis of chronic fatigue syndrome may be favourable in primary care; many patients can expect to recover in 12 months
Antidepressants are useful if a patient with chronic fatigue also has clinical depression

Although there are no systematic reviews or randomised controlled trials of prolonged rest in people with chronic fatigue syndrome, observational evidence suggests that prolonged inactivity may perpetuate or worsen fatigue and is associated with symptoms in healthy volunteers and in people recovering from viral illness.

how prevalent is this disease?

We’ve been doing epidemiological
studies over the years and if you use a broad definition, which includes for example also people who have comorbid you know concurrent depression anxiety, it may be up to 1% - 2% of the population. If you go for a narrow definition it comes down to about
0.2%-0.3%. So it’s a bit like blood pressure, it all depends on where you draw the line.


Chronic fatigue is actually a very serious condition. It’s not only more common than we previously thought but it’s probably one of the largest causes of loss of earnings in the United States and is certainly thought to be the largest cause of long term school absence.

In fact in children, probably one third of children don’t end up with qualifications after a diagnosis of chronic fatigue syndrome. And on average they miss a year of school.
And all the evidence suggests that supporting children and adults with this condition, enabling them to have access to specialist services and getting an early diagnosis is only going to help them.

Not only in terms of getting better from this illness but also in terms of preventing secondary
consequences of a long term debilitating illness. So we would encourage GP’s to make the diagnosis quickly and refer quickly
onto specialist services.

There’s lots of evidence that chronic fatigue syndrome is genetically heritable but is usually triggered by an environmental factor. And for children the environmental factor is usually an infection. In adults it often is an infection as well. One of the most common infections that we all know about is the Epstein-Barr Virus but other infections might be streptococcal.

The investigations are listed in the NICE guidelines and include full

blood count, ESR, CRP, CPK, coeliac screen, ferritin in children,
Us and Es, LFTs, and a urine dipstick as well as calcium and phosphate bone function.

Prospective studies in primary care have shown that patients with chronic unexplained fatigue are very unlikely to develop new medical diagnoses at six or 12 months' follow up.

It has been observed that people with chronic fatigue syndrome are sometimes more sensitive to the side effects of antidepressants. It's therefore always better to start antidepressants (for example a selective serotonin reuptake inhibitor) at low doses and increase gradually over two or three weeks. The final dose should be the same as the dose routinely used for people with typical depression.

Table 1: Diagnostic criteria for chronic fatigue syndrome

CDC
Oxford, UK
Clinically evaluated, medically unexplained fatigue of at least 6 months' duration that is:
Severe, disabling fatigue of at least 6 months' duration that:
Of new onset
Affects both physical and mental functioning
Not a result of ongoing exertion
Was present for more than 50% of the time
Not substantially alleviated by rest

A substantial reduction in previous levels of activity

The occurrence of four or more of the following symptoms:

Other symptoms, particularly myalgia, sleep and mood disturbance, may be present.
Subjective memory impairment

Tender lymph nodes

Muscle pain

Joint pain

Headache

Unrefreshing sleep

Postexertional malaise (>24 hours)


Exclusion criteria

Active, unresolved, or suspected disease likely to cause fatigue

Active, unresolved, or suspected disease likely to cause fatigue
Psychotic, melancholic, or bipolar depression (but not uncomplicated major depression)
Psychotic, melancholic, or bipolar depression (but not uncomplicated major depression)
Psychotic disorders
Psychotic disorders
Dementia
Dementia
Anorexia or bulimia nervosa
Anorexia or bulimia nervosa
Alcohol or other substance misuse

Severe obesity

CDC=US Centers for Disease Control and Prevention.

Standard diagnostic tests such as full blood count, thyroid function, and blood glucose

Most of the medical diseases that can lead to fatigue can be ruled out by ordering some simple blood tests. There is a consensus that, unless there is reason to, there is no need to perform any more expensive tests for the evaluation of patients with chronic fatigue in primary care.


Most of the medical diseases that can lead to fatigue can be ruled out by ordering standard diagnostic tests. If there is an abnormal finding you can order additional tests as needed.
In a study in primary care, physical examinations produced diagnostic information in 2% of patients, and laboratory investigations elucidated the cause of fatigue in 5% of patients. Minor laboratory abnormalities were relatively common but didn't contribute to the diagnostic process and didn't seem to influence the clinical outcome.

Table 2: Laboratory tests recommended for exclusion of common medical causes of chronic fatigue
Urinalysis for protein, blood, and glucose
Full blood count
Urea and electrolytes
Liver function
Thyroid function
Erythrocyte sedimentation rate or plasma viscosity
C reactive protein
Random blood glucose
Serum creatinine
Screening blood tests for gluten sensitivity
Serum calcium
Creatine kinase
Assessment of serum ferritin levels (children and young people)
Coeliac autoantibody screening (in the presence of gastro-intestinal symptoms only)

I will try to do a mental state examination for all patients presenting with fatigue

I will do those laboratory investigations that exclude reasonably common causes of chronic fatigue
I will treat patients with chronic fatigue syndrome with antidepressants if they also have clinical depression


Studies with fluoxetine, sertraline, moclobemide, and phenelzine have found insufficient evidence about the beneficial effects of antidepressants in people with chronic fatigue syndrome.

You should not advise rest. In fact, prolonged rest has been found to have adverse effects in the long run. Although there are no systematic reviews or randomised controlled trials of prolonged rest in people with chronic fatigue syndrome, observational evidence suggests that prolonged inactivity may perpetuate or worsen fatigue and is associated with symptoms in healthy volunteers and in people recovering from viral illness.

Research has found that a graded aerobic exercise programme, where participants increase their activity to up to 30 minutes of walking or swimming a day, improves measures of fatigue and physical functioning compared with flexibility training and relaxation training or general advice.
One randomised controlled trial found that an educational package to encourage graded exercise improved measures of physical functioning, fatigue, mood, and sleep at one year compared with written information alone.

A recent international study in primary care showed that recovery from chronic fatigue is the norm in primary care. Almost 65% of patients with chronic fatigue syndrome did not have fatigue at 12 months' follow up. Recovery was more likely in people without psychiatric morbidity at baseline. Other studies in primary care, however, did not report such a benign prognosis
Some patients with chronic unexplained fatigue worry that they may develop a more serious disease in the near future. But prospective studies in primary care have shown that patients with chronic unexplained fatigue are very unlikely to develop new medical diagnoses at six or 12 months' follow up.