Chronic Fatigue Syndrome (CFS) or Systemic Exertion Intolerance Disease (SEID)

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Jerry R. Balentine, DO, FACEP
    Jerry R. Balentine, DO, FACEP

    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

Quick GuideChronic Fatigue Syndrome (CFS) Symptoms and Diagnosis

Chronic Fatigue Syndrome (CFS) Symptoms and Diagnosis

What is chronic fatigue syndrome (CFS or SEID)?

Controversy about the definition of chronic fatigue syndrome (CFS) finally led an international panel of CFS research experts in 1994 to establish a precise definition of CFS so that the syndrome could actually be diagnosed. There are two criteria developed by this panel that both define and diagnose CFS. The patient must have both of the following criteria:

  1. Have severe chronic fatigue of six months or longer duration with other known medical conditions excluded by clinical diagnosis
  2. Concurrently have four or more of the following symptoms: substantial impairment in short-term memory or concentration; sore throat; tender lymph nodes in neck or armpits; unexplained muscle pain; multi-joint pain without swelling or redness; headaches of a new type, pattern, or severity; unrefreshing sleep; and post-exertion malaise lasting more than 24 hours

In addition, four symptoms of the symptoms listed above must have persisted or recurred during six or more consecutive months of illness and must not have predated the severe chronic fatigue (the symptoms must have occurred at the same time or after severe chronic fatigue appeared but not before).

Why so much controversy? There are at least three major reasons for controversy:

  1. Chronic fatigue is a symptom of many illnesses, so chronic fatigue syndrome had to have criteria that distinguished it from similar medical conditions that have chronic fatigue as a major symptom (for example, fibromyalgia, chronic mononucleosis, neurologic problems, and sensitivity to certain chemicals). Other treatable illnesses and conditions that may have chronic fatigue as one symptom among many others include hypothyroidism, cancers, autoimmune diseases, adrenal gland problems, subacute or chronic infections, obesity, sleep apnea, narcolepsy, reactions to medicines, hormonal disorders, schizophrenia, bipolar disorders, eating disorders, depression, alcohol and substance abuse, and malingering.
  2. In addition to the two criteria above needed to fit both the definition and diagnosis of CFS, many patients have additional symptoms that, depending on their severity, may predominate and overshadow the CFS symptom criteria. These symptoms include chest pain, abdominal pain, shortness of breath, chronic cough, diarrhea, nausea, night sweats, jaw pan and muscle stiffness, double vision, and psychological problems such as panic attacks, anxiety, and depression.
  3. There is no laboratory test that can give a definitive diagnosis of CFS, and there are no physical signs that specifically identify CFS.

Consequently, the disease is diagnosed by excluding the diseases that may cause the symptoms (termed a diagnosis of exclusion) listed above yet still fit the two defined criteria established by the panel of CFS experts in 1994. It is not unusual for patients to undergo an extensive battery of tests to rule out other diseases before a patient is determined to fit the CFS diagnostic criteria. Unfortunately, many patients who have subsequently been diagnosed to have CFS also have had some of the conditions and symptoms listed above. Without the CFS criteria, diagnosis would even be more controversial.

Controversy still remains. Some individuals want to rename the disease. Some clinicians want to change the 1994 criteria and others do not. Until a definitive cause is proven, controversies about names, diagnosis, treatments, and other aspects of CFS will likely remain. In February 2015, the Institute of Medicine, at the request of the CDC and others, completed a report on myalgic encephalomyelitis/chronic fatigue syndrome. The new report suggested a name change to systemic exertion intolerance disease (SEID) to better identify the disease with less prejudice and also slightly modified some criteria of the disease.

Because this report is so new and is undergoing review, it is not clear if all of it will be accepted by the medical community. The CDC has yet to make name changes in its CFS publications so this article will present information on both the current CFS and the new SEID; in most instances, the basic information has not changed (for example, cause, symptoms, and treatment).

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