Testing for Myalgic Encephalomyelitis provides a basic overview of some of the series of tests which can be done to help confirm a suspected M.E. diagnosis (and also contains further information on many other aspects of diagnosis).
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Copyright © Jodi Bassett February 2006. This version updated June 2012. From www.hfme.org
Objective evidence of quantifiable organic abnormalities in M.E. patients has existed since the 1950s. As with a wide variety of illnesses – lupus, multiple sclerosis, and ovarian cancer for example – there is as yet no single test which can diagnose M.E. in all patients. Therefore, like these other illnesses, M.E. must be diagnosed by taking a detailed medical history, noting the type and severity of symptomatology and other characteristics of the illness and the type of onset of the symptoms. (An acute or sudden onset of symptoms is always seen in M.E. and this onset type rules out a wide variety of other illnesses associated with gradual onset). A series of tests may also then be necessary to rule out or confirm a suspected M.E. diagnosis.
One cannot test for ‘CFS’ but M.E. is not the same thing as ‘CFS’ (or ‘ME/CFS.’) The presence or absence of ‘fatigue’ is largely irrelevant in determining an M.E. diagnosis except in that its presence may of course make the diagnosis of a large number of well-known fatigue causing illnesses considerably more likely (depression, vitamin deficiency or malignancy for example) (Hyde & Jain, 1992). M.E. is not a diagnosis of exclusion or an untestable disease. Tests will only all be normal in M.E. patients – as with all illnesses – if the wrong tests are conducted, or if those tested do not in fact have M.E. (Hyde 2007, [Online]) (Hyde 2006, [Online]) (Chabursky et al. 1992, p.22).
Contrary to common disinformation erroneously linking M.E. with ‘CFS,’ it is not mere ‘fatigue’ that defines M.E. but central nervous system (CNS) dysfunction. M.E. represents a major attack on the CNS by the chronic effects of a viral infection which targets the brain: an enterovirus. As M.E. expert Dr Byron Hyde explains:
The one essential characteristic of M.E. is acquired CNS dysfunction. A patient with M.E. is a patient whose primary disease is CNS change, and this is measurable. We have excellent tools for measuring these physiological and neuropsychological changes: SPECT, xenon SPECT, PET, and neuropsychological testing (2003, [Online]).
Tests which together can be used to confirm an M.E. diagnosis include:
SPECT and xenon SPECT scans of the brain. SPECT scans have demonstrated decreased cortical/cerebellar regional cerebral blood flow most frequently in the frontal, parietal, temporal, occipital and brain stem areas of the brain, and throughout the cerebral cortex in M.E. This decrease in cerebral blood flow has been found to have worsened further still 24 - 72 hours post-exertion. These abnormalities have also been shown to correlate with clinical status.
MRI scans of the brain. Punctate, subcortical areas of high signal intensity consistent with edema or demyelination have been identified by MRI in 80% or more of M.E. patients (similar to those seen in MS). M.E. patients with these MRI abnormalities have been reported as being more severely impaired than those without such abnormalities.
PET scans of the brain. PET scans of the brain have shown decreased metabolism of glucose in the right mediofrontal cortex and generalised hypoperfusion of the brain with a particular pattern of decreased neuronal metabolism in the brain stem.
EEG/QEEG brain maps. Almost all M.E. patients have abnormal cognitive-evoked EEG brain maps. QEEG brain maps are even more accurate as they have been able to demonstrate not only lack of normal activity in M.E. patients but migration of the normal activity centers from injured areas to different parts of the brain.
Neurological examination. Most M.E. patients will have an abnormal neurological exam.
Neuropsychological testing. This test can uncover the specific cognitive dysfunctions of M.E.
The Romberg test. The Romberg test is a useful test of brain stem function. Almost all M.E. patients will have an abnormal Romberg test.
Immune system tests. Natural killer cell number and function is particularly low in M.E., for example.
Insulin levels and glucose tolerance tests.
Erythrocyte Sedimentation Rate (ESR) tests. An unusually low sedimentation rate of less than 5mm/hr is common in M.E. ESR rates as low as 0 have been documented in M.E. patients. There are only five diseases that have a pathological low sedimentation level: Myalgic Encephalomyelitis, sickle-cell anemia, hereditary sperocytosis, hyper-gammaglobulinemia and hyper-fibrogenemia.
Circulating blood volume tests. This test may show a reduced circulating blood volume of up to 50%.
24 hour Holter monitor testing (a type of heart monitor). May show repetitively oscillating T-wave inversions and/or a flat T-wave and heart rates as high as (or higher than) 150 beats per minute as an immediate or delayed response to the patient maintaining an upright posture, or at rest. Heart rates as low as 40 beats per minute may also be observed (during sleep).
Tilt table examination and standing/sitting/reclining blood pressure tests. Dr Byron Hyde explains that testable vascular and cardiac dysfunction is the most obvious set of dysfunctions when looked for and is the cause behind a significant number of M.E. complaints, and that all moderate to severe M.E. patients have one or more of the following vascular dysfunctions: Severe postural orthostatic tachycardia syndrome (POTS), cardiac irregularity on minor positional changes or after minor physical activity, Raynaud’s phenomenon, circulating blood volume decrease, bowel dysfunction caused by vascular dysfunction, Persantine effect in M.E. patients, M.E. associated clotting defects, anti-smooth muscle antibodies and other cardiac dysfunctions.
Exercise testing and chemical stress tests. These tests are not appropriate for severely ill patients.
Physical exam. Physical signs of illness commonly observed in M.E. patients include:
These tests are the most critical in the diagnosis of M.E., although various other types of tests are also useful.
Positive PCR tests for enteroviral infection have been documented in a large percentage of M.E. patients that have been given this test. Enteroviruses become harder to pick up over time, although there are reports of some patients still testing positive for enterovirus infections 10 years or longer after the onset of M.E. A patient that once tested positive for enteroviral infection may return a negative test some years later. But this negative test result should not be assumed to indicate that the patient’s disease status has necessarily changed as Dr Hyde reports that whether subsequent tests were positive or negative patients remained similarly disabled (Hyde 2011, [Online]).
M.E. expert Dr Byron Hyde’s Nightingale Definition of M.E. also now makes diagnosis easier than ever before even for those with no prior experience in diagnosing M.E. This is a pure M.E. definition and, most importantly, it defines M.E. as testable (see the full-length text for details) (Hyde 2007, [Online]) (Hyde 2006, [Online]) (Hyde 2003, [Online]) (Dowsett 2001a, [Online]) (Dowsett 2000, [Online]) (Hyde 1992 p. xi) (Hyde & Jain 1992 pp. 38 - 43) (Hyde et al. 1992, pp. 25-37) (Dowsett et al. 1990, pp. 285-291) (Ramsay 1986, [Online]) (Dowsett n.d., [Online]) (Dowsett & Ramsay n.d., pp. 81-84) (Richardson n.d., pp. 85-92).
All of the information concerning Myalgic Encephalomyelitis on this website is fully referenced and has been compiled using the highest quality resources available, produced by the world's leading M.E. experts. More experienced and more knowledgeable M.E. experts than these – Dr Byron Hyde and Dr. Elizabeth Dowsett in particular – do not exist. Between Dr Byron Hyde and Dr. Elizabeth Dowsett, and their mentors the late Dr John Richardson and Dr Melvin Ramsay (respectively), these four doctors have been involved with M.E. research and M.E. patients for well over 100 years collectively, from the 1950s to the present day. Between them they have examined more than 15 000 individual (sporadic and epidemic) M.E. patients, as well as each authoring numerous studies and articles on M.E., and books (or chapters in books) on M.E. Again, more experienced, more knowledgeable and more credible M.E. experts than these simply do not exist.
This paper is merely intended to provide a brief summary of some of the most important facts of M.E. It has been created purely for the benefit of those people without the time, inclination or ability to read each of these far more detailed and lengthy references created by the world’s leading M.E. experts. The original documents used to create this paper are essential additional reading however for any physician (or anyone else) with a real interest in Myalgic Encephalomyelitis. See the full-length text or the References page.
Copyright © Jodi Bassett, January 2009. This version updated May 2009. From www.hfme.org
For more information, and to read a fully-referenced version of this text compiled using information from the world’s leading M.E. experts, please see: What is M.E.? Extra extended version. Permission is given for this unedited document to be freely redistributed. Please redistribute this text widely.
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