"40% of CFS patients seen by the Newcastle Service could in fact be diagnosed with other conditions"

Breakthrough magazine Autumn 2011

The correct diagnosis
Are we getting better at diagnosing ME/CFS?

At present, there are many ways of diagnosing ME, CFS, CFIDS, CFS/ME and ME/CFS – and just listing these acronyms illustrates the confusion that besets the field. Yet each new definition delivers only a “diagnosis of exclusion” of other conditions, based on clusters of vaguely defined symptoms shared with other illnesses. How valid a diagnosis of ME/CFS really is depends critically on the rigour of the initial clinical assessment, and the efforts expended to exclude other treatable conditions that might be causing the collection of symptoms.

The clinical guideline produced by the UK’s National Institute for Health and Clinical Excellence (NICE) in 2007 came up with its own variant of diagnostic criteria for “CFS/ ME” – new, unexplained, persistent/recurrent fatigue with a post-exercise component plus one or more of a range of common symptoms such as difficulty with sleeping, muscle and/or joint pain and headaches. …

The most important finding was that 103 (40%) of patients seen by the Newcastle Service could in fact be diagnosed with other conditions. As the Figure opposite shows, the most common alternative diagnosis in these patients was fatigue associated with a chronic disease (47% of all alternative diagnoses …). The next common alternative diagnosis was primary sleep disorder (20%), including 8 patients with obstructive sleep apnoea and 12 with another primary sleep disorder – an important finding since sleep disorders form a significant and potentially treatable diagnostic group. Furthermore, 15% of all alternative diagnoses were psychological/psychiatric illnesses (most commonly, depression, anxiety and post-traumatic stress disorder); 13% were “unexplained” but not ME/CFS (5.2% of total referrals); and 4% were cardiovascular disorders (vasovagal syncope in patients with fatigue symptoms, who also had a history of episodes of loss of consciousness, with the diagnosis made after a reproduction of symptoms in head-up tilt testing). [Other conditions included metabolic syndrome and coeliac disease.]

Prof. Newton’s results concur with those from two smaller service audits (Dundee 1993; Newcastle 2007), and reiterate that a significant minority of UK patients referred from primary care with a diagnosis of ME/ CFS can receive alternative, exclusionary diagnoses if investigated at a specialist clinic. And they illustrate that in the absence of a full clinical assessment (which most patients in the community have either never undergone, or last had many years ago), the diagnosis of ME/CFS can easily become a stopping-off point for clinically complex patients with a variety of different illnesses.

This problem is encountered not only in the UK. A fascinating commentary in 2008 in Minnesota Medicine (available online) described the difficulties experienced at a clinic in the USA for patients with fatigue, exercise intolerance and weakness (i.e., patients very like ME/CFS patients in the UK). After reporting on three paediatric cases (all of whom received serious, new diagnoses), the authors commented that, “a thoughtful and thorough physical exam can sometimes reveal otherwise hidden diagnoses”. Commentaries like this, and investigations like this one at Newcastle, certainly raise the question of which treatable diagnoses might be uncovered if all patients currently parked in the ME/CFS diagnostic layby were examined intensively at a specialist Centre of Excellence by thoughtful and thorough physicians.

The ideal would be for ME/CFS or the subtypes within to be diagnosed objectively with criteria based on clinical or laboratory measurements. …

Amen to the last.