sections include: definition by symptoms, possible origins, diagnosis and treatment
Chronic fatigue syndrome (CFS) often, but not always, begins as a flulike illness. However, unlike such infections normally, the fatigue persists even after the individual has rested or reduced his or her activity. Other CFS symptoms can include headaches, muscle pain, aching joints, swollen lymph nodes, difficulty concentrating, memory loss, “foggy” or slowed thinking, disrupted sleep, and other hard-to-measure complaints. Different people report different combinations of these secondary symptoms. Aches, pains, and other flulike symptoms are often the first signs, in addition to the medically unexplained fatigue. According to one study, 48 percent of people with CFS reported that symptoms appeared suddenly, and 40 percent said they came on gradually over time.
Eventually individuals with CFS notice they can’t keep up their previous levels of activity. This fatigue is the condition’s hallmark symptom. Family members usually perceive the individual’s reduced level of activity and might suspect the individual is suffering from a tenacious but mild flu. Typically, a person with CFS first visits a family doctor, thinking the symptoms are related to a cold or flu. When the symptoms fail to improve, or when individuals become concerned about their increasing impairment, they may seek out a specialist to ask about their fatigue. It’s not uncommon for CFS to remain undiagnosed for several years after the initial onset of symptoms.
When pain is more prominent than fatigue, doctors often identify the problem as fibromyalgia; considerable overlap exists among CFS, fibromyalgia, and other unexplained fatigue and pain conditions. Patients with these diagnoses usually feel unable to keep up with the pace of their lives and become exhausted easily. Some become so impaired that they can’t maintain their jobs or tend to other important responsibilities. For approximately 45 percent of these individuals, their illness is complicated by a concurrent psychiatric diagnosis such as depression or anxiety. For many years, in fact, most doctors believed depression or anxiety was the root cause of the fatigue in CFS. Today these psychological factors are still thought to be involved, but they may be cued or worsened by the physical problems. The different symptoms—physical and psychological—can then exacerbate each other.
Despite the many ways it can appear, the impact of CFS on a person’s life is unmistakable. It forces people to become less involved in important activities, interferes with their ability to meet responsibilities, and otherwise depletes their personal stamina and resources. Many people with CFS feel unable to meet the demands of their jobs, family, and other commitments. The condition also brings social consequences. Because there are no easily visible symptoms and because an “official” diagnosis can take so long, employers, coworkers, family members, and health care providers often misunderstand the condition and its severity. Some may assume that the individual is exaggerating or even malingering, trying to avoid responsibilities by feigning illness.
There are many myths about the cause, the best treatment, and the contagiousness of CFS. Many support groups exist and tend to be very active. They can be valuable for mutual support, and they have increased awareness of the condition among the public and medical community. But it’s important that people with CFS not let their involvement with these organizations limit or bias their evaluation of available treatments. For the sake of their own health, they must find doctors who are abreast of the latest scientific research and willing to address their specific needs.
Definition by Symptoms
CFS is defined as persistent and disabling fatigue lasting more than six months and not improving with rest or reduced activity. In addition, a person must exhibit four or more of the following symptoms over that period
- Sore throat
- Tender lymph nodes (in the neck or armpits)
- Muscle pain
- Pain in multiple joints without redness or swelling
- Headaches that are new or different since the onset of the fatigue
- Impaired short-term memory or difficulty concentrating
- Unrefreshing sleep
- Malaise or fatigue after exertion
The symptoms tend to become more severe as time passes, although most individuals report a notable fluctuation in their severity. Earlier definitions of CFS also involved fever and muscle weakness; though they’re no longer criteria for the diagnosis, people with CFS often experience them.
The symptoms of CFS commonly occur in other disorders as well, so excluding those other explanations is critical to diagnosing CFS accurately and ensuring an individual receives proper treatment. A doctor must rule out the following alternative explanations:
Possible Origins
CFS remains an unexplained illness. Its origins are unclear and may involve many factors. Several medical explanations are being evaluated by researchers, including the following.
Neurological. The most popular explanation of CFS is that an individual’s nervous system is altered, presumably by a virus or other pathogen, in a manner that reduces the normal levels of arousal and neural activity. This process would resemble the disruption caused by major depression, in which the brain’s cells and certain critical pathways become less responsive to key neurotransmitters. Another neurological explanation focuses on the hypothalamic-pituitary-adrenal (HPA) axis, a collection of structures in the brain and the endocrine system. The HPA axis is known to excite and slow neural activity, and to dictate the levels of essential hormones in the blood; it is also involved in maintaining normal sleep, in arousing the body to respond to a threat or stress, and in regulating other important functions. If this system doesn’t work normally, the body’s general ability to be aroused would be reduced.
Immunological. Another proposed explanation is that people with CFS possess an abnormally active immune system—hence an alternate term for the condition, chronic fatigue immune dysfunction syndrome (CFIDS). Essentially, the immune systems of some individuals appear to be incessantly active, waging a constant battle against a pathogen we haven’t yet identified (or, perhaps, waging that battle even though no pathogen exists). All that activity continuously drains the body’s resources. Researchers seeking an agent that might cause this immune response have examined a number of poorly understood infectious pathogens, including human herpes virus (HHV) and mycoplasma bacteria, but little evidence exists to support a specific viral or immunological cause. If people’s immune systems are being activated even in the absence of a pathogen, CFS could be related to other autoimmune disorders.
Psychological. Several mental disorders are known to produce persistent fatigue, slowed thinking and other cognitive problems, reduced energy and motivation, sleep disturbances, and other CFS symptoms. These include depression, acute anxiety, bipolar disorder, and even some psychotic disorders. It is possible, therefore, that CFS is a mental disorder that primarily affects a person in physical ways. As with many chronic illnesses, individuals who have contracted CFS often alter their daily activities and their interactions with others; inadvertently, these changes can worsen their condition. Furthermore, many people with CFS report that their symptoms improve after they try certain cognitive-behavioral psychotherapies. Whether these biopsychosocial factors play a role in producing CFS, continuing it, or both is not yet known.
Chronobiological. Fatigue and pain are common complaints of people with chronic sleep disturbances. CFS might be the result of a sleep disorder or disruption of the body’s mechanisms for inducing and maintaining restorative sleep on a regular cycle. Depression and pain are both known to interfere with sleep cycles. Research into this theory is inconclusive but continues to focus on sleep patterns, sleep quality, and physiological markers of the body’s circadian rhythms.
Cardiovascular. Some evidence suggests that CFS is related to the body’s inability to maintain optimum blood pressure. Some people with CFS show decreased ability to alter blood pressure in response to challenges as simple as standing up. For these hypotensive individuals, parts of the body may not be getting enough blood and vital nutrients during physical exertion or psychological stress. This might produce fatigue and postexertion malaise. There is no evidence that CFS is contagious or has a genetic component. There does not seem to be an increase in the prevalence of CFS among family members or among children of those with the disorder.
Diagnosis and Treatment
There are no definitive tests for chronic fatigue syndrome, and treatment is largely supportive. However, some patients may very well have an organic illness that can be identified by testing. For example, some cases of CFS are associated with the Epstein-Barr virus. In addition, many patients with CFS symptoms are suffering from depression or other psychiatric disorders that present these symptoms as well. The lack of biological diagnostic tools for CFS, as a result, requires physicians to make a “diagnosis of exclusion.” That is, they cannot diagnose CFS without ruling out the other diseases that may have these symptoms.
Only a qualified physician can make a diagnosis of CFS. The process of eliminating the other possible causes of an individual’s symptoms starts with a physical examination and a clinical interview. The physical exam determines the presence of fever or swollen lymph nodes, and the extent of symptoms. The interview is required to assess the severity of the person’s fatigue, the degree of impairment, and the presence of any mental disorder. Blood tests are often used to rule out an infection or other fatiguing illness. Neurological and neuropsychological examinations determine the extent of neurological and cognitive dysfunctions and rule out other diagnoses. Even brain imaging is occasionally useful for excluding other neurological diseases.
People diagnosed with CFS should seek physicians experienced with treating the condition and related disorders. There is no specialty dedicated to CFS, but specialists in internal medicine and neurology may have a better understanding of the condition. While an early diagnosis may allow a person to start receiving care sooner and thus reduce the severity of symptoms, it may not influence the final outcome.
Currently, there are no specific treatments and no known cure for CFS. Instead, doctors use treatments known to reduce the symptoms and thus increase a person’s ability to function. The clinical goal is improvement in a person’s quality of life despite the chronic fatigue. Doctors can recommend various techniques that have been shown to help many people with CFS. By using their personal resources efficiently, these people have returned to a normal level of functioning. Interventions that have proven useful include:
- medication for the symptoms, both physical and psychological
- carefully tailored exercise
- cognitive-behavioral therapies, including stress management and sleep hygiene
Many people with CFS are also clinically depressed to some degree, which can worsen their symptoms or interfere with recovery. Antidepressant medications, exercise, stress management, and better sleep habits may all be useful for this problem.
Whenever individuals with CFS hear about new treatments, especially those not recommended by their primary physician, they should consider the possible adverse consequences. One common danger is becoming overmedicated, dependent on painkilling or psychiatric drugs. Making extreme behavioral and lifestyle changes increases stress, at least in the short run, and may isolate people from their supportive social networks. In some situations, treatment may actually increase fatigue, reduce stamina, and worsen the condition overall.
People with CFS tend to get better. As many as 10 percent report a complete recovery. Most people diagnosed with the condition return to an acceptable level of functioning and ability, though too few return to their workplaces after becoming disabled. Periodically, an individual’s CFS symptoms will become less or more difficult; the challenge is to manage a fluctuating but chronic illness. A portion of people with CFS report that their symptoms and impairment persist for ten or more years after the onset of their fatigue. It’s not yet clear what differentiates these individuals from the majority, or what influences the progression and remission of their symptoms.
back to top