IOM report calls for new criteria, new name for chronic fatigue syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS, should be renamed systemic exertion intolerance disease to better convey the complexity, severity, and key symptomatology of this very real illness, according to a new report from the Institute of Medicine.

The IOM committee that wrote the report also developed new evidence-based diagnostic criteria for the disorder based on an extensive literature review and input from patients, caregivers, and clinicians, and recommended that it be assigned a new code in the International Classification of Disease, Tenth Edition (ICD-10).

According to the new criteria proposed by the IOM Committee on the Diagnostic Criteria for ME/CFS, a diagnosis requires evidence of three core symptoms, which can typically be identified by a thorough patient history, physical examination, and medical work-up. The core symptoms include:

• A substantial reduction or impairment in the ability to engage in pre-illness levels of activities. This impairment should be accompanied by fatigue, which is often profound, and which is of new or definite onset rather than the result of ongoing excessive exertion, and is not substantially alleviated by rest.

• Postexertional malaise following physical, cognitive, or emotional stress.

• Unrefreshing sleep.

Additionally, patients should have cognitive impairment and/or experience orthostatic intolerance. The symptoms should persist for at least 6 months at a moderate, substantial, or severe intensity at least half of the time.

“This disorder should be diagnosed when individuals meet the criteria,” Dr. Ellen Wright Clayton, the committee chair, said during a press briefing on the report.

The diagnosis should be made regardless of whether patients have comorbid conditions unless another condition explains all of the patient’s symptoms.

“That is extremely unlikely. The point that we’re trying to make is that it is incumbent on the clinician to make the diagnosis, to think about comorbidities – because they are common – and if there are comorbidities to diagnose them and treat them, but that their existence does not preclude a diagnosis of this disorder,” said Dr. Clayton, a professor of pediatrics and law, and cofounder of the Center for Biomedical Ethics and Society at Vanderbilt University, Nashville.

Also, the 6-month duration criteria is important for distinguishing the disorder from other fatiguing disorders that resolve in less than 6 months, but it is important to understand that even if symptoms haven’t persisted for 6 months, they need to be identified and treated, she said.

“These patients have real symptoms, and they deserve real care and real therapy whether they meet the criteria for this disorder or not,” she added.

The same is true for pediatric patients, according to Dr. Peter Rowe, director of the Chronic Fatigue Clinic at Johns Hopkins Children’s Center in Baltimore.

Dr. Rowe noted that the condition is relatively common in the pediatric population, and can have profound effects on the social and educational development of children and adolescents.

“It is one of the most common causes of prolonged school absence, and it is time to put to rest the notion that this represents either school phobia or school refusal. The point is that it isn’t that these children don’t want to go to school, it’s that they can’t,” he said during the briefing.

The pediatric evidence base is much smaller than the adult evidence base, and many more data are needed to understand the disease in children, but the available evidence is sufficient to show that “orthostatic intolerance and autonomic dysfunction are common in pediatric ME/CFS, that the neurocognitive abnormalities – while not present at baseline when patients are tested in the supine position – will emerge when patients are tested under conditions of orthostatic stress or if another condition like distraction is introduced,” he said.

There clearly is a high prevalence of profound fatigue, unrefreshing sleep, and postexertional exacerbation of symptoms in children, just as there is in adults, and the evidence is strong that the condition can follow acute infectious mononucleosis or Epstein-Barr virus in some patients, he added.

The duration of illness is similar to that in adults, and the condition does not require a specific pediatric definition, he said.

To assist clinicians with making an appropriate diagnosis, and to promote the use of the new criteria, the committee recommended that the U.S. Department of Health & Human Services develop a toolkit for use in a variety of clinical settings. The kit will replace currently available tools, which are too complex and too difficult to use in a busy clinical practice, Dr. Clayton said.

The aim is to enable all clinicians, including primary care physicians, emergency medicine doctors, and subspecialists to make this diagnosis, she added.