I. What is CFS?

In determining a case of CFS, the first portions of this section (A. and B1.) largely follow the 1994 CDC definition, the text of which can be found on page 3 of the Ruling.

“The CDC and other medical experts characterize CFS, in part, as a syndrome that causes prolonged fatigue lasting 6 months or more, resulting in a substantial reduction in previous levels of occupational, educational, social or personal activities.”

Using the CDC definition, the Ruling makes clear that a “physician should make a diagnosis of CFS only after alternative medical and psychiatric causes of chronic fatiguing illness have been excluded.”

Major hallmark symptom

“...clinically evaluated, unexplained, persistent or relapsing chronic fatigue that is of new or definite onset (has not been lifelong); is not the result of ongoing exertion; cannot be explained by another physical or mental disorder; is not substantially alleviated by rest; and results in substantial reduction in previous levels of occupational, educational, social, or personal activities;”

Additional symptoms of CFS

Diagnostic symptoms: “the concurrence of four or more of the following symptoms, all of which must have persisted or recurred during 6 or more consecutive months of illness and must not have predated the fatigue:

• post-exertional malaise lasting more than 24 hours;
• self-reported impairment in short-term memory or concentration severe enough to cause substantial reduction in previous levels of occupational, educational, social, or personal activities;
• sore throat;
• tender cervical or axially lymph nodes;
• muscle pain;
• multi-joint pain without joint swelling or redness;
• headaches of a new type, pattern, or severity;
• waking unrefreshed”

An applicant’s physician must document and validate the ME/CFS diagnosis by using the CDC definition and when able, also by the CCC and ICC definitions. Diagnosis is made by symptoms, medical signs and medical/laboratory tests. Hence, any of the above diagnosis symptoms should be included.

Other symptoms

However, in section B2., “Other Symptoms”, the Ruling expands the list of CFS diagnostic symptoms as more recently outlined in the Canadian Criteria and the International Consensus Criteria:

“Other Symptoms. Within these parameters, the CDC case definition, CCC, and ICC describe a wide range of other symptoms a person with CFS may exhibit, in addition to the CDC symptoms.

• Muscle weakness;
• Disturbed sleep patterns (for example, insomnia, prolonged sleeping, frequent awakenings, or vivid dreams or nightmares);
• Visual difficulties (for example, trouble focusing, impaired depth perception, severe photosensitivity, or eye pain);
• Orthostatic intolerance (for example, lightheadedness, fainting, dizziness, or increased fatigue with prolonged standing);
• Respiratory difficulties (for example, labored breathing or sudden breathlessness);
• Cardiovascular abnormalities (for example, palpitations with or without cardiac arrhythmias);
• Gastrointestinal discomfort (for example, nausea, bloating, or abdominal pain); and
• Urinary or bladder problems (for example, urinary frequency, nocturia, dysuria, or pain in the bladder region).”

As will be seen later, the inclusion of these common elements of CFS allows for an increased ability to provide medical evidence of the illness in terms of the necessary documentation of medical signs and laboratory testing.

Co-occurring conditions

In the last subsection 3 is the following text:
“Co-occurring Conditions. People with CFS may have co-occurring conditions, such as fibromyalgia (FM), myofascial pain syndrome, temporomandibular joint syndrome, irritable bowel syndrome, interstitial cystitis, Raynaud's phenomenon, migraines, chronic lymphocytic thyroiditis, or Sjögren's syndrome. Co-occurring conditions may also include new allergies or sensitivities to foods, odors, chemicals, medications, noise, vibrations, or touch, or the loss of thermostatic stability (for example, chills, night sweats, or intolerance of extreme temperatures).”

Here, again, the new Ruling (based on the more recent CFS/ME and ME definitions) includes many more of the essential elements of the illness that increase the physician’s ability to provide medical documentation. Many of these “co-occuring conditions” are essential symptoms of CFS and their documentation add to diagnostic clarity. Notably, multiple sensitivities and loss of thermostatic stability have for years been known to patients and educated clinicians, but are now just being fully recognized.

Other conditions that may explain symptoms similar to CFS 

The Ruling reads: “Additionally, several other disorders (including, but not limited to FM, multiple chemical sensitivity, and Gulf War Syndrome, as well as various forms of depression, and some neurological and psychological disorders) may share characteristics similar to those of CFS. When there is evidence of the potential presence of another disorder that may adequately explain the person's symptoms, it may be necessary to pursue additional medical or other development. As mentioned, if we cannot find that the person has an MDI of CFS but there is evidence of another MDI, we will not evaluate the impairment under this SSR. Instead, we will evaluate it under the rules that apply for that impairment.”

Therefore, in documenting a diagnosed case of CFS, the treating physician(s) should not only document any co-occurring conditions, but also should be sure to, if possible, clearly differentiate CFS from other conditions that may share over-lapping symptoms.