Chronic Fatigue Syndrome
If you find yourself wishing for a nap every now and then, feeling listless and depressed as well as experience joint and muscle pain, or suffer from recurrent headaches, chances are that you are suffering from Chronic Fatigue Syndrome (CFS). Chances also are that you are not alone. Chronic fatigue syndrome affects 0.2-1 % of the population in the United States (1, 2) with over a million people suffering from CFS. Women are more susceptible to CFS as compared to men. Typically, people in their 40s and 50s are more likely to suffer from CFS. However, CFS has been detected in children, teenagers and people of all age groups suffering from prolonged disorders like cancer. Although it is a syndrome that is present in almost all ethnic groups and countries, with a similar incidence rate worldwide, the diagnosis and treatment of chronic fatigue syndrome is a challenging task. Chronic fatigue syndrome has been noted in individuals of all social and economic classes and it is suspected that this disorder may show a familial pattern of incidence.
Chronic fatigue syndrome may also have severe social implications for those afflicted by this disease like loss of employment owing to reduced attention and inputs or breakdown of marriages or other relationships.
Definition of Chronic Fatigue Syndrome
Chronic fatigue syndrome presents with a wide array of symptoms including, of course, disabling fatigue, memory loss, headaches and loss of concentration. Muscle pain, feverishness, sore throat, lack of sleep or unrefreshing sleep, post-exercise exhaustion lasting for more than 24 hours, joint swelling and loss of professional competence are also symptoms of chronic fatigue syndrome. Tender in the lymph nodes in the armpit and around the neck is also a typical symptom of CFS. These symptoms indicate CFS when they last for a period of more than six months or show repeated occurrence within a span of six months or more(1,2). According to the Center for Disease Control, USA (CDC), chronic fatigue syndrome is diagnosed if at least four of these symptoms are simultaneously present in a patient. At the same time, the physician must also be able to establish that other organic illnesses that can result in fatigue are not detected in the patient, symptomatically as well as with biochemical diagnostic tests. It is vital to eliminate other physical and psychological causes of distress that show similar symptoms in order to diagnose CFS. Since self-reportage of symptoms is a valuable step in the diagnosis of this complex disease, patients must take care to understand and categorize their symptoms clearly when approaching a doctor.
Given that the signs and symptoms of CFS are not unique to this disease alone, a diagnosis of CFS can be made based only on symptoms reported by the patient combined with elimination of other probable causes. Unfortunately, biochemical diagnostic tests are not yet available for CFS although efforts are on to devise these (3). For a physician, it is important to distinguish between and rule out depression before diagnosing a patient with chronic fatigue syndrome. Often CFS patients also have other morbidities like dry eyes or mouth, diarrhea, tingling sensations on skin, dizziness, jaw pain and nausea to name a few. A comprehensive list of the associated morbidities can be looked up from the case definition for CFS provided by the CDC at: http://www.cdc.gov/cfs/general/case_definition/complete.html
The additional co-morbidities present with CFS do not actually contribute to CFS but nonetheless, they make diagnosis of CFS difficult.
What causes Chronic Fatigue Syndrome?
As can be expected from the complex symptoms and presentation of CFS, the pathology (causes and manner of progression of disease) of CFS is also not fully understood. CFS can result from several causes which are currently being researched to understand the mechanisms of development of CFS. Viral infections or flu-like bouts of illness have been noted in patients just before the onset of CFS (2). These include infection with enteroviruses, Hepatitis C virus, Herpes virus -6 and Epstein-Barr virus. Likewise, infections with Chlamydia pneumoniae and Coxiella burnetii may also trigger CFS even after treatment with antibiotics which help to eliminate the primary infection.
A specific virus named xenotropic Murine leukemia virus-like virus (XMLV) was considered as a sole causative agent of CFS (4) in 67% patients in an American study. However, these results have been questioned by other scientists who have not found any association between XMRV and CFS (5, 6). Erlwein and colleagues were not able to detect XMRV in the blood samples of 186 British patients who were diagnosed with CFS according to criteria laid down by the CDC.
Stress is another factor that is likely to trigger CFS, especially emotional stress that affects the pituitary gland and hypothalamus. Stress factors that affect this neuroendocrine gland also result in increased secretions of corticosteroids from the adrenal glands, leading to the development of CFS (2). Emotional stress also results in increasing the susceptibility of people to viral infections and so increases the chances of developing CFS.
Chronic fatigue syndrome has also been associated with other maladies like a chronic autoimmune disorder as well as treated or untreated cancer (7). In such cases, the constant stress resulting from chronic illnesses tends to suppress the production of hormones from adrenal glands (situated on top of the kidney), leading to CFS. In a strange twist, CFS may persist in cancer survivors as well (8-11).
A preliminary study has linked CFS with exposure to organophosphate fertilizers in British sheep farmers (12), however, this line of investigation of CFS certainly requires more proof.
Mycoplasma infections have also been shown in patients suffering from CFS in Europe (13) as well as North America (14). Mycoplasmas are bacteria that are resistant to penicillin and other penicillin-like antibiotics.
Therapies for Chronic Fatigue Syndrome
Needless to say that since the exact pathogenesis of CFS is still unknown, therapeutic approaches for treating CFS have not been established conclusively.
Since viral and bacterial infections are likely to trigger CFS, it follows that aggressive treatment against these agents can be a first line of defense against CFS as well (2). Moderate levels of exercise may help in overcoming CFS though people suffering from CFS may have prolonged recovery periods after exercise. For CFS patients, graded exercise therapy that is customized for every patient may be a suitable approach.
Cognitive behavioral therapy, similar to that used in other psychiatric disorders like depression, may also be used as a therapy in treating CFS. Cognitive behavioral therapy has been effective in treating CFS in kids and teenagers, resulting in increased attendance and performance at school (15).
There are preliminary studies that consumption of fish oil and evening primrose oil may help to reduce the severity of CFS (16). Eicosapentenoic acid (EPA) found in fish oil is likely to help in reducing effects of stress on the hypothalamic-pituitary-adrenal gland system, thereby providing some relief from CFS (2). Evening primrose oil has shown a small therapeutic benefit against placebo when treating CFS associated with viral illness (15) but the evidence is based on a small number of patients.
Intramuscular magnesium injection, dietary supplements and oral intake of nicotinamide adenine dinucleotide (NAD) and oral galantamine have been tried out as therapies against CFS. However, there is no clear evidence to support their benefit in treating CFS.
Sleep pattern correction therapies and anti-depressants are likely to have some benefits for patients who report unrefreshing sleep as well as depression along with CFS but these approaches are more likely to be subjective than generic.
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