Do you have chronic fatigue syndrome?

Many conditions can make you tired. Problematically, ‘chronic fatigue’ is used medically to describe the tiredness that often accompanies chronic illness such as hepatitis, multiple sclerosis and depression. The name trivialises what can be a severe condition, and CFS definitions have been vague; for that reason, many people prefer the internationally and historically used term ‘myalgic encephalomyelitis‘ which reflects the nervous system and immune aspects of the condition, with an emphasis on post-exertional symptoms as the single consistent criteria. Current research now often uses ‘myalgic encephalomyelitis/chronic fatigue syndrome'(ME/CFS).

Research efficacy has been reduced when studies have used loose criteria which do not carefully excluding those who are primarily depressed and not acknowledging the primary differentiating feature of post-exertional exacerbation (PEM/PENE). For example, the 2007 NICE criteria required only fatigue and one other symptom, such s nausea or headaches. Studies found the Canadian ME/CFS criteria identified patients with more functional impairments and greater physical, mental, and cognitive problems than those who met CFS Fukuda et al. criteria (50-75% met me/cfs criteria), likewise for ME by the ICC criteria. Difference in case definitions account for wide discrepencies in prevalance estimates, with generalised CFS definitions (such as the 1991 Oxford CFS Criteria which required only severe, disabling fatigue). For a comparison of case criteria, see the IOM comparison table.

The more recent IOM suggestion is the definition of ‘systemic exertion intolerance disease’, though this has a number of limitations as well (see twisk 2015, jason, or twisk 2016). Some have argued there may not evidence of inflammation in the brain, however a number of articles have now been published on neuroinflammation. ME/CFS has also been called EBV/ Post viral syndrome , Chronic Fatigue Immune Dysfunction Syndrome or even low natural killer syndrome, which was first defined in 1987.

There is also the similar condition of CIRS (mold, chronic Lyme) which has similar symptoms and the addition of red leaky eyes and electric shocks. See the related page.

The 2011 international consensus criteria for ME is as follows.

Myalgic encephalomyelitis is an acquired neurological disease with complex global dysfunctions. Pathological dysregulation of the nervous, immune and endocrine systems, with impaired cellular energy metabolism and ion transport are prominent features. Although signs and symptoms are dynamically interactive and causally connected, the criteria are grouped by regions of pathophysiology to provide general focus.
 A patient will meet the criteria for postexertional neuroimmune exhaustion (A), at least one symptom from three neurological impairment categories (B), at least one symptom from three immune/gastro-intestinal/genitourinary impairment categories (C), and at least one symptom from energy metabolism/transport impairments (D).
A. Postexertional neuroimmune exhaustion (PENE pen’-e): Compulsory
 This cardinal feature is a pathological inability to produce sufficient energy on demand with prominent symptoms primarily in the neuroimmune regions. Characteristics are as follows:
 1. Marked, rapid physical and/or cognitive fatigability in response to exertion, which may be minimal such as activities of daily living or simple mental tasks, can be debilitating and cause a relapse.
 2. Postexertional symptom exacerbation: e.g.acute flu-like symptoms, pain and worsening of other symptoms.
 3.Postexertional exhaustion may occur immediately after activity or be delayed by hours or days.
 4. Recovery period is prolonged, usually taking 24 h or longer. A relapse can last days, weeks or longer.
 5. Low threshold of physical and mental fatigability (lack of stamina) results in a substantial reduction in pre-illness activity level.
Operational notes: For a diagnosis of ME, symptom severity must result in a significant reduction of a patient’s premorbid activity level. Mild (an approximate 50% reduction in pre-illness activity level), moderate (mostly housebound), severe (mostly bedridden) or very severe (totally bedridden and need help with basic functions). There may be marked fluctuation of symptom severity and hierarchy from day to day or hour to hour. Consider activity, context and interactive effects. Recovery time: e.g. Regardless of a patient’s recovery time from reading for ½ hour, it will take much longer to recover from grocery shopping for ½ hour and even longer if repeated the next day – if able. Those who rest before an activity or have adjusted their activity level to their limited energy may have shorter recovery periods than those who do not pace their activities adequately. Impact: e.g. An outstanding athlete could have a 50% reduction in his/her pre-illness activity level and is still more active than a sedentary person.
B. Neurological impairments
At least one symptom from three of the following four symptom categories
 1. Neurocognitive impairments
  a. Difficulty processing information: slowed thought, impaired concentration e.g. confusion, disorientation, cognitive overload, difficulty with making decisions, slowed speech, acquired or exertional dyslexia
  b. Short-term memory loss: e.g. difficulty remembering what one wanted to say, what one was saying, retrieving words, recalling information, poor working memory
 2. Pain
  a. Headaches: e.g. chronic, generalized headaches often involve aching of the eyes, behind the eyes or back of the head that may be associated with cervical muscle tension; migraine; tension headaches
  b. Significant pain can be experienced in muscles, muscle-tendon junctions, joints, abdomen or chest. It is noninflammatory in nature and often migrates. e.g. generalized hyperalgesia, widespread pain (may meet fibromyalgia criteria), myofascial or radiating pain
 3. Sleep disturbance
  a. Disturbed sleep patterns: e.g. insomnia, prolonged sleep including naps, sleeping most of the day and being awake most of the night, frequent awakenings, awaking much earlier than before illness onset, vivid dreams/nightmares
  b. Unrefreshed sleep: e.g. awaken feeling exhausted regardless of duration of sleep, day-time sleepiness
 4. Neurosensory, perceptual and motor disturbances
   a. Neurosensory and perceptual: e.g. inability to focus vision, sensitivity to light, noise, vibration, odour, taste and touch; impaired depth perception
   b. Motor: e.g. muscle weakness, twitching, poor coordination, feeling unsteady on feet, ataxia
Notes: Neurocognitive impairments, reported or observed, become more pronounced with fatigue. Overload phenomena may be evident when two tasks are performed simultaneously. Abnormal accommodation responses of the pupils are common. Sleep disturbances are typically expressed by prolonged sleep, sometimes extreme, in the acute phase and often evolve into marked sleep reversal in the chronic stage. Motor disturbances may not be evident in mild or moderate cases but abnormal tandem gait and positive Romberg test may be observed in severe cases.
C. Immune, gastro-intestinal and genitourinary Impairments
At least one symptom from three of the following five symptom categories
 1. Flu-like symptoms may be recurrent or chronic and typically activate or worsen with exertion. e.g. sore throat, sinusitis, cervical and/or axillary lymph nodes may enlarge or be tender on palpitation
 2. Susceptibility to viral infections with prolonged recovery periods
 3. Gastro-intestinal tract: e.g. nausea, abdominal pain, bloating, irritable bowel syndrome
 4. Genitourinary: e.g. urinary urgency or frequency, nocturia
 5. Sensitivities to food, medications, odours or chemicals
Notes: Sore throat, tender lymph nodes, and flu-like symptoms obviously are not specific to ME but their activation in reaction to exertion is abnormal. The throat may feel sore, dry and scratchy. Faucial injection and crimson crescents may be seen in the tonsillar fossae, which are an indication of immune activation.
D. Energy production/transportation impairments: At least one symptom
 1. Cardiovascular: e.g. inability to tolerate an upright position – orthostatic intolerance, neurally mediated hypotension, postural orthostatic tachycardia syndrome, palpitations with or without cardiac arrhythmias, light-headedness/dizziness
 2. Respiratory: e.g. air hunger, laboured breathing, fatigue of chest wall muscles
 3. Loss of thermostatic stability: e.g. subnormal body temperature, marked diurnal fluctuations; sweating episodes, recurrent feelings of feverishness with or without low grade fever, cold extremities
 4. Intolerance of extremes of temperature
Notes: Orthostatic intolerance may be delayed by several minutes. Patients who have orthostatic intolerance may exhibit mottling of extremities, extreme pallor or Raynaud’s Phenomenon. In the chronic phase, moons of finger nails may recede.
Paediatric considerations
Symptoms may progress more slowly in children than in teenagers or adults. In addition to postexertional neuroimmune exhaustion, the most prominent symptoms tend to be neurological: headaches, cognitive impairments, and sleep disturbances.
 1. Headaches: Severe or chronic headaches are often debilitating. Migraine may be accompanied by a rapid drop in temperature, shaking, vomiting, diarrhoea and severe weakness.
 2. Neurocognitive impairments: Difficulty focusing eyes and reading are common. Children may become dyslexic, which may only be evident when fatigued. Slow processing of information makes it difficult to follow auditory instructions or take notes. All cognitive impairments worsen with physical or mental exertion. Young people will not be able to maintain a full school programme.
 3. Pain may seem erratic and migrate quickly. Joint hypermobility is common.
Notes: Fluctuation and severity hierarchy of numerous prominent symptoms tend to vary more rapidly and dramatically than in adults.
——— Myalgic encephalomyelitis
——— Atypical myalgic encephalomyelitis: meets criteria for postexertional neuroimmune exhaustion but has a limit of two less than required of the remaining criterial symptoms. Pain or sleep disturbance may be absent in rare cases.
Exclusions: As in all diagnoses, exclusion of alternate explanatory diagnoses is achieved by the patient’s history, physical examination, and laboratory/biomarker testing as indicated. It is possible to have more than one disease but it is important that each one is identified and treated. Primary psychiatric disorders, somatoform disorder and substance abuse are excluded. Paediatric:primary’ school phobia.
Comorbid entities: Fibromyalgia, myofascial pain syndrome, temporomandibular joint syndrome, irritable bowel syndrome, interstitial cystitis, Raynaud’s phenomenon, prolapsed mitral valve, migraines, allergies, multiple chemical sensitivities, Hashimoto’s thyroiditis, Sicca syndrome, reactive depression. Migraine and irritable bowel syndrome may precede ME but then become associated with it. Fibromyalgia overlaps.

See full study and accompanying research of the above ICC definition here. The Canadian Clinical Case definition of ME/CFS  is similar (see overview).

This is in contrast to other less stringent definitions of ‘chronic fatigue syndrome’ such as the 1994 Fukuda study summarised by the US CDC (center of disease control) criteria which focuses primarily on fatigue, but does not require post-exertional malaise (which is defined by others as a necessary component for diagnosis), causing confusion as those with other fatigue causes such as depression may qualify. In Australia, the Royal Australasian College of Physians clinical recommendations vague 2002 recommendations (following on from Hickie’s  1995 criteria) require only fatigue for six months, and-

Four or more of the following symptoms that are concurrent, persistent for six months or more and which did not predate the fatigue:

  • Impaired short term memory or concentration

  • Sore throat

  • Tender cervical or axillary lymph nodes

  • Muscle pain

  • Multi-joint pain without arthritis

  • Headaches of a new type, pattern, or severity

  • Unrefreshing sleep

  • Post-exertional malaise lasting more than 24 hours

This makes post-exertional malaise optional, whereas the ME and newer definitions hold it as a core symptom. The problems of such wide ‘CFS’ definitions (defined as 6 months of fatigue without a requirement for post-exertional exacerbation) create a highly varied group. The focus on 6 months of fatigue delays diagnosis and rest; especially as early rest was considered initially to be the primary decider of whether or not someone would recover by Ramsey; this has been replicated in more recent studies, where severity was determined by early management.

The original 1956-1986 definitions of Myalgic Encephalomyelitis by Dr. A. Melvin Ramsay:

A syndrome initiated by a virus infection, commonly in the form of a respiratory or gastrointestinal illness with significant headache, malaise and dizziness sometimes accompanied by lymphadenopathy or rash. Insidious or more dramatic onsets following neurological, cardiac or endocrine disability are also recognised.

Characteristic features include:
(1) A multisystem disease, primarily neurological with variable involvement of liver, cardiac and skeletal muscle, lymphoid and endocrine organs.
(2) Neurological disturbance – an unpredictable state of central nervous system exhaustion following mental or physical exertion which may be delayed and require several days for recovery; an unique neuro-endocrine profile which differs from depression in that the hypothalamic/pituitary/adrenal response to stress is deficient; dysfunction of the autonomic and sensory nervous systems; cognitive problems/ Neurological disturbance, especially of cognitive, autonomic and sensory functions, often accompanied by marked emotional lability and sleep reversal.
(3) Musculo-skeletal dysfunction in a proportion of patients (related to sensory disturbance or to the late metabolic and auto immune effects of infection)
/Generalised or localised muscle fatigue after minimal exertion with prolonged recovery time.
(4) A characteristically chronic relapsing course/An extended relapsing course with a tendency to chronicity.
(5) Marked variability  of symptoms both within and between episodes.

Ramsey noted ‘Practically without exception they complain of coldness in the extremities and many are found to have abnormally low temperatures of 94-95F (34-35c). In a few, these are accompanied by bouts of severe sweating even to the extent of waking during the night lying in a pool of water…Many report difficulty in saying the right word and are conscious of the fact that they continue to say the wrong one. Others find that they start a sentence but cannot complete it, while some others have difficulty comprehending the written or spoken word. A complaint of acute hyperacusis is not infrequent; this can be quite intolerable but alternates with periods of normal hearing or actual deafness. Vivid dreams…’ He also states ‘The unique form of muscle fatiguability described above is virtually a sheet-anchor in the diagnosis of Myalgic Encephalomyelitis and without it a diagnosis should not be made’ and notes tenderness in the trapezii and calves.

Objections have been raised this element is absent from suggested criteria, however PEM descriptors tend to include ‘“Muscle weakness”, “Physically drained/sick after mild activity”, “Minimum exercise makes you physically tired”, “Next-day soreness after non-strenuous activities”, and “Dead, heavy feeling after starting to exercise” (Jason, 2015).

Ramsey disagreed  with ‘post viral syndrome’ on the basis of a lack of intra-daily variations and lack of chronicity.

History of ‘CFS’

In 1881, Beard described a similar syndrome as ‘neurasthenia.’ In 1934, an outbreak occurred at the Los Angeles General Hospital where 198 employees suffered from rapid muscle weakness, clonic twitches and cramps, ataxia, severe pain aggravated by exercise, and neck and back stiffness. In 1937 and 1939, two outbreaks with similar symptoms were reported in Switzerland. In 1955, at the Royal Free Hospital in London, 292 patients suffered from fever and persistent fatigue. From then on, the name ‘Royal Free Disease’ was used. In 1984, researchers described the chronic Epstein-Barr virus syndrome. It was characterized by a combination of atypical symptoms (fatigue, sore throat, fever, myalgia, etc.) in the absence of any objective clinical signs. The hypothesis at that time suggested a latent Epstein-Barr infection, although no antibodies were detected in the serum of patients. Aspecific physical and psychological complaints emerging after the Gulf war in 1991-1992, were designated as the Gulf war syndrome and showed similarities with CFS. The term chronic fatigue syndrome appeared in the 1980s to define the syndrome without knowing the exact etiology of the disease; became worldwide after publication of a set of criteria by the United States Centers for Disease Control and Prevention (CDC) in 1994 (the original CDC had  2 major and 8/11 minor symptoms, fukuda reduced this to one major and 4/8).

For a history of the definition of ME/CFS, see Dowsett.

The definition of ME/CFS has been controversial. Some pages, such as the hummingbird website, take the concept of ME to the extreme and look at it as a life-threatening, acute and narrowly defined condition. This differs to the 2015 IOM or international consensus definition, as outlined above. Other groups (such as Disapedia/arainbowatnight) staunchly maintain that ME & CFS are different conditions, as summarised here:



Read about Dysautonomia & POTS here.

It has been estimated that 20-70% of the patients with FM meet the criteria for CFS. Conversely, 35-70% of those with CFS also have FM.

Note: ME/CFS had more physical functioning problems and bodily pain but similar mental and emotional functioning.