Chronic fatigue syndrome

Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. The root cause(s) of the disease are unknown and the mechanisms are not fully understood. Distinguishing core symptoms are lengthy exacerbations or flare-ups of the illness following ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to accomplish tasks that were routine before the illness; and sleep disturbances. The Center for Disease Control and Prevention's (CDC) diagnostic criteria also require at least one of the following: (1) Orthostatic intolerance (difficulty sitting and standing upright) or (2) impaired memory or attention. Frequently and variably, other common symptoms occur involving numerous body systems, and chronic pain is very common. The often incapacitating fatigue in CFS is different from that caused by normal strenuous exertion, is not significantly relieved by rest, and is not due to a previous medical condition. Diagnosis is based on the person's symptoms because no confirmed diagnostic test is available. Proposed mechanisms include biological, genetic, epigenetic, infectious, and physical or psychological stress affecting the biochemistry of the body. Persons with CFS may recover or improve over time, but some will become severely affected and disabled for an extended period. No therapies or medications are approved to treat the cause of the illness; treatment is aimed at alleviation of symptoms. The CDC recommends pacing (personal activity management) to keep mental and physical activity from making symptoms worse. Limited evidence suggests that counseling, personalized activity management, and the use of rintatolimod help improve some patients' functional abilities. About 1% of primary-care patients have CFS; estimates of incidence vary widely because various epidemiological studies have used dissimilar definitions. It has been estimated that 836,000 to 2.