New research on chronic fatigue has just been published and we would like to stress again the importance of an accurate assessment before diagnosing patients with a particular disorder such as Chronic Fatigue Syndrome (CFS).
CFS is a condition of prolonged and severe fatigue or tiredness not relieved by rest, but whose symptoms can often be confused with sleepiness caused by a sleep disorder. Symptoms may include profound exhaustion, poor quality sleep, musculoskeletal pain, impaired physical and mental functioning, headaches, possible low-grade fever, and occasional painful lymph nodes among others.
Very few studies have successfully found any potential causes of CFS. However, a recent study suggests that a viral syndrome may be involved for some patients. CFS was found to be linked to a retrovirus according to results published in the Proceedings of the National Academy of Sciences. The study analyzed the gene sequence of chronic fatigue patients and found that 86.5% carry the murine leukemia virus (MLV) in their blood in contrast to only 6.8% of healthy patients. Although these study results are helpful in elucidating potential causes of chronic fatigue, it is important to note that sleep disorders were not evaluated in this study.
In the field of Sleep Medicine, we often see patients who come to our clinic with a diagnosis of CFS given by an outside physician, only to be discovered through a comprehensive sleep evaluation that the patient actually has a sleep disorder such as obstructive sleep apnea or narcolepsy as the cause of the underlying “fatigue” or sleepiness. Once the sleep disorder is treated, the sleepiness and fatigue in many of these patients completely resolves.
Sleepiness and “fatigue” are terms often erroneously used interchangeably by patients and the medical community, likely contributing to confusion about differentiating these two symptoms. Sleepiness is associated with a physiological tendency to fall asleep or nod off when sitting inactive in a boring situation, whereas fatigue is associated with malaise or low energy but no increased tendency to nod off. Fatigue is commonly associated with many medical conditions, including hypothyroidism and depression to name a few. The distinction between fatigue and sleepiness is very important. Up until a few years ago, medical textbooks on CFS have not even included sleep disorders as part of a list of possible medical conditions that need to be evaluated before making a diagnosis of CFS.
A clear prevalence of CFS among the US population is unknown, perhaps highlighting the ambivalence pertaining to the diagnostic criteria of this disorder. At our Institute, we recommend that patients undergo a comprehensive sleep medicine evaluation to differentiate sleepiness from fatigue and to rule out a sleep disorder as a potential underlying cause. If you have been diagnosed with chronic fatigue syndrome, please seek a referral with a comprehensive sleep medicine specialist to reassess your condition. You may not have chronic fatigue syndrome. And yes, you may be helped!