There is much discussion about particular criteria for the diagnosis of ME, CFS, PVFS, CFS/ME or ME/CFS – just listing these acronyms makes the head spin. But, in the absence of hard data from real patients, much of the speculation generates more heat than light, and produces more angst than understanding. That’s why the results of a recent investigation on patients from the Maes Clinic in Belgium are so valuable.

The investigators raised the question of whether clinical differences could be observed between CFS patients with post-exertional symptoms and those without such symptoms. Using statistical models, they found that a combination of fatigue, a subjective feeling of infection, and post-exertional malaise defined groups of patients in which distinct differences in clinical symptoms (and inflammatory biomarkers) could be found. Their conclusion was that whilst the traditional (Fukuda) definition of CFS can adequately distinguish between CFS and uncomplicated ‘chronic fatigue’, patients fulfilling the Fukuda definition should be subdivided into those with post-exertional malaise and those without.

Interestingly, the UK’s NICE Clinical Guideline of 2007 insists that post-exertional symptoms should be present for a diagnosis of ‘CFS/ME’ to be made, so the importance of post-exercise symptoms is already recognised formally. The challenge remains to get GPs and healthcare professionals to apply the criteria in practice when diagnosing patients in the clinic.

Reference: Myalgic Encephalomyelitis (ME), Chronic Fatigue Syndrome (CFS), and Chronic Fatigue (CF) are distinguished accurately: results of supervised learning techniques applied on clinical and inflammatory data. Maes M et al. Psychiatry Res 2012 Dec 30; 200(2-3): 754-60.