Chronic fatigue syndrome goes by several different names, including systemic exertional intolerance disease and myalgic encephalomyelitis. There is a wide range of symptoms associated with it, but the most characteristic is fatigue without an apparent cause that does not improve with rest and worsens with either mental or physical exertion.
According to the Mayo Clinic, the cause of chronic fatigue syndrome is unknown. It appears to be a combination of congenital predispositions on which other factors may act as a trigger. There is no cure, but treatments are available for symptom management. CFS is difficult to diagnose for various reasons.
Symptoms mimic other conditions
Fatigue is a symptom associated with a wide range of other medical problems. Chronic conditions such as hypothyroidism, anemia or diabetes may all cause fatigue. Sleep disorders such as restless leg syndrome or obstructive sleep apnea can cause excessive tiredness by disrupting the body’s natural sleep cycle. Mental health conditions such as anxiety and depression can also cause fatigue.
Further complicating the problem of diagnosis is that conditions such as these may be present in a person with CFS but not be the cause of the symptoms.
Testing has limitations
Perhaps because its cause is mysterious, there is no single test to conclusively confirm or rule out a diagnosis of CFS. Instead, the diagnosis involves testing for, and gradually ruling out, other possible causes of the symptoms. If other tests are negative and doctors are unable to find a condition that would explain the symptoms, the process of elimination leaves CFS as the most probable diagnosis.
Misdiagnosis of CFS as another condition may subject the patient to unnecessary and ineffectual treatments.