Prolonged fatigue and a wide range of other symptoms, lasting at least 6 months
- Most common between the ages of 25 and 45
- More common in females
- Genetics and lifestyle are not significant factors
Chronic fatigue syndrome is a complex illness that produces extreme fatigue over a prolonged period. The condition has also been called post-viral fatigue syndrome, myalgic encephalomyelitis (ME), or chronic fatigue and immune dysfunction syndrome. The condition can be extremely debilitating and may continue for months or years.
Since the symptoms are so variable, chronic fatigue syndrome is often unrecognized or misdiagnosed. This makes it difficult to estimate the number of people affected, but it is thought to be about 250,000 in the UK. The condition is most often seen in women aged between 25 and 45, but it can affect children or adults of any age and people from all ethnic groups.
What are the causes?
The cause of chronic fatigue syndrome is unknown, although it is believed that several different factors are likely to be involved. In some cases, chronic fatigue syndrome develops after recovery from a viral infection or after an emotional trauma, such as bereavement. In other cases, there is no specific preceding illness or life event. Sometimes, chronic fatigue syndrome is associated with depression, although it is unclear whether depression is a result of the condition or a cause of it.
What are the symptoms?
Although the number and severity of symptoms may vary, the major symptoms of chronic fatigue syndrome are:
Extreme tiredness lasting at least 6 months.
Impairment of short-term memory or concentration.
Tender lymph nodes.
Muscle and joint pain without swelling or redness.
Prolonged muscle fatigue and feeling ill after even mild exertion.
Many people who have chronic fatigue syndrome also develop symptoms of depression, such as loss of interest in their work and leisure activities, or of anxiety (see Anxiety disorders). Conditions involving an allergic reaction, such as eczema and asthma, may become worse in people who have chronic fatigue syndrome.
How is it diagnosed?
Your doctor may suspect chronic fatigue syndrome if you have had prolonged fatigue for more than 6 months with no obvious cause and you also have at least four of the other symptoms listed here. However, since persistent tiredness is a symptom of many other disorders, including an underactive thyroid gland or adrenal glands (see Hypothyroidism, and Addison’s disease) and anaemia, your doctor will try to exclude other causes first.
Your doctor will probably perform a general physical examination, and he or she may ask you questions to find out if you have psychological problems, such as depression. Blood tests may also be arranged. If no underlying cause is identified, a diagnosis of chronic fatigue syndrome will be made if your symptoms meet the criteria. Since there is no specific diagnostic test for chronic fatigue syndrome, confirmation of the disorder can take some time.
What is the treatment?
Although there is no specific treatment for chronic fatigue syndrome, there are a number of self-help measures that may help you to cope with the condition (see Coping with chronic fatigue syndrome). Your doctor may give you drugs to help to relieve some of your symptoms. For example, headaches and muscle and joint pain may be relieved by painkillers or nonsteroidal anti-inflammatory drugs. Antidepressant drugs may produce an improvement in your condition even if you have not developed symptoms of depression. You may find cognitive–behavioural therapy beneficial. A course of physiotherapy will help to build up your stamina. Your doctor may suggest counselling to help you to cope with your illness, and joining a support group may also be helpful.
What is the prognosis?
Chronic fatigue syndrome is a long-term disorder, but there may be periods of relief from some symptoms. Many people find symptoms are worst in the first 1–2 years. In more than half of all cases, the condition clears up after several years.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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