ME/CFS

About ME/CFS

Widely used criteria from the U.S. National Academy of Medicine describe a substantial reduction in activity for at least six months with profound fatigue that isn't relieved by rest, post-exertional malaise and unrefreshing sleep, plus either cognitive impairment or orthostatic intolerance (symptoms that worsen when upright).

ME/CFS often begins after an infection. Severity ranges widely, and some people are housebound or bedbound. Major health bodies recognize it as a serious multisystem disease.

Common symptoms and challenges

• Post-exertional malaise, which can be delayed by a day or more and last days to weeks
• Unrefreshing sleep
• Brain fog, slowed thinking and memory problems
• Light-headedness or a racing heart when upright
• Muscle or joint pain, headaches, and sensitivity to light, sound or chemicals
• Sore throat, tender lymph nodes or flu-like feelings

Biological factors

Emerging research: Studies have found differences in immune function, energy metabolism and mitochondrial function, the autonomic nervous system, and the gut microbiome in people with ME/CFS. Large genetic studies have begun to identify regions of the genome associated with the illness. These findings are important for research, but none has yet become a diagnostic test.

Laboratory testing

There is no diagnostic biomarker for ME/CFS. A clinician makes the diagnosis based on symptoms and history, and uses routine tests to look for other conditions that can cause similar symptoms, such as thyroid disease, anemia or sleep disorders.