Causes and treatment of CFS and myalgic encephalopathy
Predisposing and aggravating factors for chronic fatigue syndrome - a controversial condition for which official guidance on diagnosis and treatment is due in August this year - were discussed at a London seminar earlier this year.
|
Key points
|
After more than three years of consultations with stakeholders - including physicians, therapists and patient groups - the National Institute for Health and Clinical Excellence (NICE) is due to publish a clinical guideline on diagnosis and management of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (or encephalopathy)1.
These two terms describe a much studied but little understood group of complaints - affecting 3%-4% of the UK population - that are defined only by the medically unexplained symptoms with which they are associated, including: severe fatigue of more than six months' duration, musculoskeletal pain, impaired concentration and headaches, concomitant depression and anxiety.
In line with the biopsychosocial approach to such conditions - which emphasises controlled return to work as an important aspect of rehabilitation - earlier this year, NHS Plus issued a set of guidance documents on occupational aspects.2
What is known about causes, aggravating factors, co-morbidities and best available treatments was the subject of a London seminar organised by the Royal Society of Medicine (RSM) in January this year.3
Opening the RSM meeting, Dr Anthony Cleare, reader in affective disorders at the Institute of Psychiatry, King's College London, noted that, while CFS is often thought of as a relatively new condition, "neurasthenia" - effectively the same condition - was the subject of a treatise published in the 19th century.4
CFS is defined as new onset fatigue (that is, fatigue of at least six months' duration but not lifelong) that results in substantial disability, is not caused by exertion or alleviated by rest and where there is concurrent occurrence of at least four associated symptoms (concentration/memory impairment, sore throat, recurrent tender lymph nodes, headaches, muscular or joint pain, unrefreshing sleep and post-exertional malaise). CFS is considered to exist where there is no medical or psychiatric explanation for these symptoms.
Although there is no single cause of CFS, Cleare noted, there are certain factors that render people vulnerable to the condition and factors that can trigger it.
Predisposing factors that can increase the risk of developing CFS or fibromyalgia5 include: being female (1.5 times, perhaps up to two times, more common); having a past history of psychiatric disorder; tending to attribute symptoms to a somatic cause; having an early life history of illness in close family members; and having a history of fatigue or other medically unexplained symptoms. In addition, recent research suggests that there may be some genetic factors and that those with a history of childhood abuse or trauma may be at a higher risk of CFS. Cleare pointed out that while the latter factor is often missed, it is actually quite a significant risk factor.
One study looked at history of abuse among a group of patients with fibromyalgia and a group of patients with rheumatoid arthritis (RA). It found that, among those with fibromyalgia, 30%-40% had experienced childhood abuse or sexual abuse; this compared with around 15% ofthose with RA. Adulthood abuse showed an even higher correlation, with up to two-thirds with fibromyalgia having suffered some kind of abuse6.
Whereas common viruses - coughs, colds, flu - do not show a high rate of development of CFS in sufferers when followed up six months later, more severe viral infections can lead to this post-viral fatigue syndrome. A study of the risk of chronic fatigue in those with viral meningitis found that, after six months, 25% of participants still had chronic fatigue. Cleare pointed out that, while this figure did not relate to strictly defined CFS, the rate for chronic fatigue was well above what it would usually be (which is benchmarked at around 0.5%-1%). Similarly, glandular fever - caused by the Epstein-Barr virus - and viral hepatitis had higher rates of chronic fatigue after six months (16% and 20% respectively).
There are specific risk factors for someone going on to develop chronic fatigue after one of these infections. For example, someone with a past psychiatric illness will be five times more likely to be fatigued six months after recovery from the infection.
Co-existing psychiatric disorders
A simple study looking at psychiatric disorder in CFS sufferers found that, while 25% had no psychiatric diagnosis, 50% had depression and a quarter had other psychiatric disorders. These figures might be higher than other reports have shown but, generally, studies suggest that between a half and three-quarters of CFS patients do have a co-existing psychiatric disorder, Cleare said.
A further study looked at whether psychiatric disorder is simply secondary, comparing depression in CFS with depression in other medical control groups (RA, myopathy, multiple sclerosis and some form of neuromuscular disorder). In all the samples, the rate of depression was between two and five times higher among those with CFS, showing a clear link between CFS and psychiatric disorder.
Cleare then turned to perpetuating factors, explaining that both psychological and social factors can have an impact.
One study that looked at the link between depression and pain compared patients with normal mood with patients with depression and those with one or more depressive symptoms but who were not clinically depressed. Overall, depressed patients were four times more likely to suffer aches and pains.
As well as psychiatric disorder, psychological perpetuating factors include cognitive and behavioural factors. Cognitive factors involve individuals experiencing a feeling of loss of control over symptoms - particularly a belief that exercise or activity can be harmful - and tending to focus heavily on symptoms. Behavioural factors include the use of avoidance as a coping strategy and prolonged recuperation. While avoidance and recuperation can be helpful in the short term, in the long term it can lead to chronic disability. As Professor Trudie Chalder, of King's College London, discussed in her presentation, people constantly talk about the potential harmful effects of activity, but harmful effects of rest should also be pointed out.
Chalder explained that studies have shown that cognitive behavioural therapy (CBT) can reduce fatigue and increase function in CFS patients. Patients tend to be particularly receptive to the fact that there is a link between physiological, cognitive and behavioural responses and, if they change their behaviour, it will in turn change their physiological response and their cognitive response. Chalder emphasised the collaborative nature of treatment and the aim of showing patients that they have some power and control over the process. They should be encouraged to identify the connection between the symptoms that they are experiencing and their mood and the way in which they think about things, and to make the link between symptoms getting worse and negative thoughts.
Nevertheless, in discussions about rehabilitation with patients, Chalder noted, language that might alienate them should be avoided. For example, patients may not be very happy with the term "cognitive behaviour therapy" because it implies a psychosomatic cause. "The focus of any discussion should be on how to manage symptoms rather than the cause of symptoms," Chalder said. "Psychological discussion should be avoided and physical-illness analogies used instead." Chalder also noted there was evidence that certain factors were predictors of poor outcome following CBT. These included a history of serious depression, older age, being in receipt of invalidity benefits or negotiating ill-health retirement and, controversially, belonging to a self-help organisation.
1. Chronic fatigue syndrome/myalgic encephalomyelitis (or encephalopathy): diagnosis and management (expected publication date: 22 August 2007), National Institute for Health and Clinical Excellence (orders: 0870 155 5455 and doh@prolog.uk.com), http://guidance.nice.org.uk/topic/cfsme.
2. Occupational aspects of the management of chronic fatigue syndrome: a national guideline (with summaries for employers, for employees and for healthcare professionals), NHS Plus, www.nhsplus.nhs.uk/CMS.
3. Royal College of Physicians, 16 January 2007.
4. Beard G (1880). A practical treatise on nervous exhaustion (neurasthenia). New York: William Wood and Company.
5. There is significant overlap - up to 80% - between CFS and fibromyalgia.
6. Walker EA, Keegan D, Gardner G et al. "Psychosocial factors in fibromyalgia compared with rheumatoid arthritis: II. Sexual, physical, and emotional abuse and neglect". Psychosomatic Medicine 59, 572-7.
This article was written by Sophie Cheetham, former assistant editor, Occupational Health Review.
