People with CFS/ME suffer from pain, extreme tiredness and viral symptoms.
From the 1930s-1950s, outbreaks of disease marked by prolonged fatigue were reported in the US and elsewhere.
First thought to be a psychiatric disorder, CFS is now recognized as a severe physical illness, although the uncertainty of its origin has plagued progress in diagnosis and treatment.
However, growing evidence of physiological biomarkers is now emerging.
A broad spectrum
CFS and myalgic encephalomyelitis (ME), together known as CFS/ME, is a complex, acquired, chronic and multi-system disease, involving systemic exertion intolerance and resulting in significant relapse after exertion of any sort.
While symptoms vary, CFS/ME can involve immune, neurological and cognitive impairment, sleep abnormalities and dysfunction of the autonomic system, which controls several basic bodily functions, resulting in significant functional impairment accompanied by profound fatigue.
The onset of symptoms may be sudden – for example, immediately following a viral illness – or gradual, with no apparent link to a specific event or time.
Effects can range from moderate to severely debilitating. At least 25% of patients are bedbound or housebound at some point in the illness, and many never regain their pre-disease level of functioning.
Although CFS/ME is now established as a genuine illness, lack of progress in pinning down its elusive diagnosis and treatment continues to frustrate patients, carers and professionals.
Difficulties with diagnosis
According to the Centers for Disease Control and Prevention (CDC), CFS/ME affects a million plus Americans, and it has been reported in children under 10 and seniors over 70. Ronald Davis, a biochemist and geneticist at Stanford University in Palo Alto, CA, puts the figure between 836,000 and 2.5 million.
Fatigue is only a part of this complex condition.
In addition, the International Association for Chronic Fatigue Syndrome and Myalgic Encephalomyelitis (IACFS/ME) estimate that up to 80% of people with the disease in the US have not yet been diagnosed.
The condition is so broad and variable that most criteria require patients to show symptoms for at least 6 months before it can be diagnosed, and diagnosis depends heavily on exclusion of other conditions.
Medical providers may be uncomfortable diagnosing and treating it, and patients have reported difficulty finding a knowledgeable physician.
Because the pathology of CFS/ME remains unknown, there is currently no blood or other biological test that can be used to diagnose it.
Even the criteria for diagnosis is disputed. According to British psychiatrist Prof. Sir Simon Wessely, of King’s College London in the UK, there are up to 20 different sets of criteria, causing frustration for patients and making the results of scientific studies difficult to compare.
Criteria produced by the CDC are widely used, but advocates such as the UK’s ME Association note that some people with genuine ME/CFS do not have a sufficient number of different symptoms to fulfill the strict CDC definition.
Scientific progress has also been limited by lack of funding for research: around $6 million a year in the US, less than the funding for agent orange and dioxin, according to figures from the National Institutes of Health (NIH). Others put the figure as low as $5 million.
Variability of symptoms and severity poses a challenge
One challenge with both diagnosis and research is the broad spectrum of the disease, as this impacts both the degree to which individuals are affected and the results of any survey.
The prognosis, for example, ranges from a small percentage who regain normal health over time, to a further small percentage who experience continued deterioration.
Between these extremes, a majority fluctuate between good and bad periods of health and relapses or exacerbations caused by infections, operations, temperature extremes or stressful events. A significant minority stabilize but remain severely affected, requiring constant practical and social support.
CFS and ME diagnosis: are they the same?
Diagnosis is further complicated by the question: are CFS and ME the same? Does the name reflect the disease?
Some advocates argue that ME has more systemic features, whereas CFS is more focused on fatigue, or that the choice of “fatigue” in the terminology has belittled the condition, implying that patients just feel “tired all the time.”
Dr. Michael Zeinah, of Stanford University, CA, who is currently studying abnormalities in the brain relating to the disease, told Medical News Today that “most would consider these [terms] synonymous.”
Prof. Sir Simon Wessely, president of the UK’s Royal College of Psychiatrists, told MNT:
“I don’t think it matters too much what we call it, what matters is what we can do about it. What […] matters is that I and any other doctor take it seriously, give them time, believe they are ill and have something to propose.”
A modified version of the World Health Organization (WHO) ICD-9-CM diagnosis, used for insurance assessment in the US, presents ME and CFS in the same document: separate but overlapping neurological disorders.
In February 2015, MNT reported that the Institute of Medicine (IOM) proposed changing the name to systemic exertion intolerance disease (SEID), to which some advocates were cautiously optimistic.
The NIH initiative and PACE
In October 2015, the NIH announced plans to strengthen efforts to advance CFS/ME research, including increasing funding, creating a new working group and bringing CFS/ME under the umbrella of the National Institute of Neurological Disorders and Stroke (NINDS), which advocates consider “a meaningful prerequisite for progress.”
The announcement came as the latest findings from the UK’s PACE trial were published, as reported by MNT. The study has drawn criticism from the CFS/ME community on a number of counts.
On the next page we look at the ongoing search for treatment options for CFS/ME.