Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia Syndrome (FMS) are complex illnesses that can be debilitating. There is a wide overlap of symptoms in ME/CFS and FMS. Many believe that they are variants of the same or similar disease process or pathogenesis. ME/CFS and FMS are distinguished from one another on the basis of symptom balance. ME/CFS patients have greater post-exertional malaise and/or fatigue, more severe fatigue, cognitive dysfunction, and immune dysfunction. FMS patients have greater pain and musculoskeletal dysfunction.
Although ME/CFS and FMS share a number of symptoms, ME/CFS is commonly triggered by a viral infection, whereas FMS is commonly triggered by a physical trauma, most often involving the spine. ME/CFS can be distinguished from FMS patients by the confirmed breakdown of one of the body's antiviral defense pathways.
A number of other illness have many symptoms in common with ME/CFS and or FMS.
A few of them are: