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Dr. Byron Hyde describes M.E. & CFS

"Where M.E. and CFS overlap, they undoubtedly represent the same illness, however, due to the considerable definitional and conceptual differences, CFS and M.E. should not be considered the same illness."
-Dr. Byron Hyde-

Dr. Byron Hyde, founder of the Nightingale Research Foundation, Ottawa, Canada, has written some of the most insightful articles on the clear distinctions between historically described M.E. and the current CFS definitions.  He has also been vocal in criticizing the methods, creation of, and flaws in the CDC CFS definitions  (see sidebar).


"Thirty years ago when a patient presented to a hospital clinic with unexplained fatigue, any medical school physician would have told the students to search for an occult malignancy, cardiac or other organ disease or chronic infection. The concept that there is an entity called chronic fatigue syndrome has totally altered that essential medical guideline. Patients are now being diagnosed with CFS as though it were a disease. It is not. It is a patchwork of symptoms that could mean anything. The original concepts of searching for occult disease are relevant to patients today with CFS, ME and other fatiguing illnesses. Furthermore, because you do not find pathology does not mean there is none."  Byron Hyde MD

© 2009 Byron Hyde MD

Missed Diagnoses
Myalgic Encephalomyelitis
Chronic Fatigue Syndrome

With a Forward by
Prof. Malcolm Hooper

Also available at Amazon.com

Excerpts from:

The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)

"...what this definition does today is (a) separate clearly M.E. from CFS and (b) demonstrate that M.E. is an early diagnosable and provable disease - as are all true diseases, and (c) assist in the early treatment and cure of M.E. patients."
-Dr. Byron Hyde-

Primary M.E. is an acute onset biphasic infectious disease process, where there is always a measurable and persistent diffuse vascular injury of the Central Nervous System in both the acute and chronic phases. Primary M.E. is associated with immune and other pathologies.

Primary M.E. is a chronic disabling, acute onset biphasic epidemic or endemic infectious disease process affecting both children and adults. There are both central and peripheral aspects to this illness.

A: The Central Nervous System (CNS) symptoms, as well as the clinical and technological abnormalities, are caused by a diffuse and measurable injury to the vascular system of the Central Nervous System. These changes in the organization of the CNS are caused by a combined infectious and immunological injury and their resulting effect on CNS metabolism and control mechanisms. Much of the variability observed in an M.E. patientís illness is due to the degree and extent of the CNS injury and the ability of the patient to recover from these injuries.

B: A significant number of the initial and long-term peripheral or body symptoms, as well as clinical and technological body abnormalities in the M.E. patient, are caused by variable changes in the peripheral and CNS vascular system. The vascular system is perhaps the largest of the bodyís organs and both its normal and pathological functions are in direct relationship to CNS and peripheral vascular health or injury, to CNS control mechanisms and to the difficulty of the peripheral vascular system and organs to respond to CNS neuro-endocrine and other chemical and neurological stimuli in a predictable homeostatic fashion.

C: When pain syndromes associated with M.E. occur, they are due to a combined injury of (i) the posterior spinal cord and / or posterior root ganglia and appendages, (ii) patho-physiological peripheral vascular changes, and (iii) CNS pain reception homeostasis mechanisms.

Depending upon the degree and extent of the ongoing CNS and peripheral vascular injuries, these patho-physiological changes in turn may give rise to both transient and in many cases permanent systemic organ changes in the patient.

As with any illness, the diagnostic criteria of M.E. are divided into two sections:

(a) The clinical features and history of the ill patient that alert the physician to the initial diagnosis

(b) The technological examinations that confirm to the physician proof of the diagnosis.

Clinical Features

The clinical features of Myalgic Encephalomyelitis are consistent with the following characteristics that can easily be documented by the physician.

1. M.E. is an acute onset biphasic epidemic or endemic infectious disease:  Both
Epidemic and Non-Epidemic cases are often preceded by a series of repeated minor infections in a previously well patient that would suggest either a vulnerable immune system, or an immune system subject to overwhelming stressors.... [see details about the types of immune stressors in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)]

2. Primary Infection Phase: The first phase is an epidemic or endemic (sporadic) infectious disease generally with an incubation period of 4 to 7 days; in most, but not all cases, an infection or infectious process is evident.

3. Secondary Chronic Phase: The second and chronic phase follows closely on the first phase, usually within two to seven days; it is characterized by a measurable diffuse change in the function of the Central Nervous System. This second phase is the persisting disease that most characterizes M.E.

4. The Presence or Absence of Various Pain Syndromes is highly variable: The pain syndromes associated with the acute and chronic phases of M.E. may be described as Early and Late findings. Early Findings: (a) severe headaches of a type never previously experienced; (b) these are often associated with neck rigidity and occipital pain; (c) retro-orbital eye pain; (d) migratory muscle and arthralgia pain; (e) cutaneous hypersensitivity. Late Findings: Any of the early finding plus (f) fibromyalgia-like pain syndromes. This is only a partial list of the multiple pain syndromes. Many of the pain features tend to decrease over time but can be activated or increased by a wide range of external and chemical stressors.

Testable & Non-testable Criteria

The technological tests listed below can be used to (a) confirm the clinical diagnosis of Myalgic Encephalomyelitis and (b) to some degree gauge its severity and probability of persistence. The second and chronic phase that clearly defines M.E. is characterized by various measurable and clinical dysfunctions of the cortical and/or sub-cortical brain structures.

5. Diffuse Brain Injury Observed on Brain SPECT:  [see details about the types and degrees of brain injury in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)]

6. Testable Neuropsychological Changes: There are neuropsychological changes that are measurable and demonstrate short-term memory loss, cognitive dysfunctions, increased irritability, confusion, and perceptual difficulties. There is usually rapid decrease in these functions after any physical or mental activity. [see details about the types of neuropsychological changes in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)]

7. Testable Major Sleep Dysfunction: This can include all forms of sleep dysfunction. [see details about specific types of sleep dysfunction in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)]

8. Testable Muscle Dysfunction: This feature may be due to vascular dysfunction or peripheral nervous or spinal dysfunction and includes both pain and rapid loss of strength of muscle function after moderate physical or mental activity. This feature tends to improve over a period of years but many patients frequently remain permanently vulnerable to new disease episodes.  Unfortunately only a few major medical centres are equipped to study this type of dysfunction.

9. Testable Vascular Dysfunction: This is the most obvious set of dysfunctions when looked for and is probably the cause behind a significant number of the above complaints. All moderate to severe M.E. patients have one or more and at times multiple of the following vascular dysfunctions.  As noted, the primary vascular change is seen in abnormal SPECT scans and clinically most evident in patients with:

a. POTS: severe postural orthostatic tachycardia syndrome. [More details]
b. Cardiac Irregularity: on minor positional changes or after minor physical activity, including inability of the heart to increase or decrease in speed and pump volume in response to increase or decrease in physical activity. [More details]
c. Raynaudís Phenomenon [More details]
d. Circulating Blood Volume Decrease:
this is a nuclear medicine test in which the circulating red blood cell levels in some M.E. patients can fall to below 50%, preventing adequate oxygenation to the brain, gut and muscles. This is undoubtedly a subcortical dysregulation. It is associated with serum and total blood volume measurements. This is a concept that many physicians have difficulty understanding.[More details]
e. Bowel Dysfunction:
vascular dysfunction may be the most significant causal basis of the multiple bowel dysfunctions occurring in M.E. (See d. above.)
f. Ehlers-Danlos Syndromes Group
[More details]
g. Persantine Effect in M.E. Patients
[More details]
h. M.E. Associated Clotting Defects
[More details]
i.  Anti-smooth muscle Antibodies [More details]
j.  Cardiac Dysfunction:
 There are a large number of cardiac dysfunctions that can regularly appear in an M.E. patient.  Without a clear understanding of these significant problem areas it is simply indefensible and potentially dangerous to place and unsuspecting patient in a graduated exercise program. [More details]

[More in-depth details about the testable vascular dysfunction in #9 above can be found in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)]

10. Testable Endocrine Dysfunction: These features are common and tend to be of late appearance. It is most obvious in:

a. Pituitary-Thyroid Axis  [More details]

The following changes, while uncommon, may also be related to an M.E.disease process:
b. Pituitary-Adrenal Axis Changes:
where changes and findings are infrequent.
c. Pituitary-Ovarian Axis Changes
d. Bladder Dysfunction Changes 
[More details]

[More details about testable endocrine dysfunction in #10 can be found in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)]

[Further discussion on the foundations and implementation of this definition, as well as updated additions follow this list of criteria in the complete version of The Nightingale Definition of Myalgic Encephalomyelitis (M.E.)  Treatment recommendations are also addressed in the Discussion section.  References included.]

As with all definitions, the Nightingale Research Foundationís Definition of Myalgic Encephalomyelitis will have to be looked at by many clinicians and researchers and increasingly knowledgeable patients over the years, disagreed about, changed and improved upon. But what this definition does today is (a) separate clearly M.E. from CFS and (b) demonstrate that M.E. is an early diagnosable and provable disease - as are all true diseases, and (c) assist in the early treatment and cure of M.E. patients.

This Nightingale Research Foundationís Definition will be available with any updates or corrections, on the Nightingale Research Foundationís Website, http://www.nightingale.ca. This definition may be copied, translated, distributed by electronic or hard copy and may be included, in whole or in part in any publication without permission from the Nightingale Research Foundation or the authors, provided that this last paragraph and referral back to our website are noted.

Byron Marshall Hyde MD, Ottawa - January 29, 2007

Excerpts from:

Are Myalgic Encephalomyelitis and Chronic Fatigue Syndrome
Synonymous Terms?

by Dr. Byron Hyde

On differentiating ME and CFS: "At the 1998 M.E. /CFS conference in Australia, both Myalgic Encephalomyelitis and Chronic Fatigue Syndrome were used to describe a chronic illness. This paper is a discussion on the similarities and differences in these two terms that may lead to scientific difficulties. The author suggests that the definitional criteria and epidemic history of Myalgic Encephalomyelitis (M.E.) and the inclusion criteria are significantly different from the CDC definitions and history. The three typical phases of M.E. are discussed. A brief review of some of the known deaths in phase 2 of M.E. are also mentioned."

On ME/CFS deaths: [Found in the section of this essay on phases of the illness, described as #1: prodromal phase; #2: Principal Illness, and #3: chronic phase].  Of note in phase 2, "Very infrequent deaths have been known to occur in this phase and usually are represented by two different pathophysiologies.  Dr. John Richardson of Newcastle upon Tyne, U.K. has noted deaths in professional athletes who return to active professional sports, 'to work off the flu'. Cause of death has been attributed to orthostatic cardiac irregularity. It is also during this phase that CNS deaths occurred in the Cumberland Epidemic, in the Akureyri epidemic, and in one of the Mediterranean epidemics." [Editor's note:  Although this paper was written in 1998, current research and two recently publicized ME/CFS deaths in 2005 in the US and UK support these historic observations. The young U.S. man's autopsy showed extensive inflammation and viral damage to his heart; the young U.K. woman's autopsy showed extensive inflammation to her spinal cord.  See the News page to read brief reports of these deaths and link to more information.]

More on the similarities and differences between ME and CFS: "Where M.E. and CFS overlap, they undoubtedly represent the same illness, however, due to the considerable definitional and conceptional differences, CFS and M.E. should not be considered to be the same illness. In phase #3, the M.E. patient is always prone to unusual and persisting muscle and CNS fatigability after relatively normal physical or intellectual exertion. The patients are not chronically fatigued. When unstressed physically, intellectually or emotionally, the M.E. patient appears totally normal and often has no difficulty doing very short-term tasks. The problem is above all, one of endurance and once exhausted, the increasingly lengthy time to recover to a reasonable degree of activity."

Dr. Hyde also analyzes historic M.E. epidemics: "There appears to be a high prevalence of epidemics or clusters in schools, hospitals and institutions involving hospital staff. Teachers, residential students or students engaged in team sports or orchestras traveling in groups appear more affected. British and previous Australian researchers have been historically more interested in the enterovirus association. Enterovirus infections have an incubation period identical to incubation periods noted in most of the M.E. epidemics, that is, of 4-6 days. Documented deaths have occurred in several M.E. epidemics, but are best documented in the Cumberland epidemic and were well known in the Akureyri epidemic. All of these deaths involved CNS injury. The Akureyri epidemic involved at least 7 prepubertal children in Friedrikshavn who developed M.E. followed by Parkinson-like illness and died.  Documented deaths in sporadic cases of M.E. are known, but it is my experience that treating physicians often become vitriolic when the deaths are attributed to M.E by the families of the deceased. M.E. and CFS may be the only illnesses in history from which some physicians believe the patient is invulnerable to death."

"Important Differences That Distinguish M.E. from CFS"

"This M.E. definition is important in that unlike the CDC definitions of Chronic Fatigue Syndrome, the Wallace and Ramsay definitions of M.E. observes the importance the initial acute variable infectious type illness associated with subnormal temperatures. They then note the important secondary and resulting chronic illness characterized by CNS and the autonomic nervous system features and intellectual and muscle dysfunctions and their chronic persistence. Enlarged cervical lymph nodes and pharyngitis are almost never observed in the chronic phases of M.E. and yet by definition, they form part of the characteristic findings in CFS. M.E. is also distinguished from CFS in that multiple organ involvement, seizure activity, death, and autonomic nervous system dysfunction occur in M.E. and by definition, these simply do not occur in CFS. Perhaps the most important difference is that chronic fatigue, by definition occurs in 100% of CFS patients. In M.E. chronic fatigue is not an essential factor, but rapid CNS and muscular fatigability with a pathologically slow recovery or loss of stamina is an essential finding. In M.E., the illness, the disease process, its investigation and pathology starts on the day the patient ceases to be well. In CFS, the Atlanta based CDC has decreed that the disease process starts only on the first day of the sixth month.

Having stated this, after having examined more than 2,000 chronic CFS patients, I have almost never found, (1) enlarged cervical glands, (2) obvious pharyngitis, or (3) elevated temperature. Why is this? It is my belief that the initial CDC definition, was created by a group of well meaning researchers and physicians who, with two or three exceptions, had for all purposes never routinely seen or examined CFS patients. Further, it is my opinion, that this group of well meaning individuals, were initially so complicit in believing that EBV was the cause of CFS, that they simply incorporated diagnostic features of infectious mononucleosis (glandular fever) into the CDC, CFS definition. It is a telling fact, that with the exception of two, perhaps three, of the original sixteen authors of the CDC definition, the majority have never again published on CFS or ever routinely seen and examined any CFS patients. It is also important to note that three of the physicians, who had the longest experience with M.E./CFS patients, withdrew from the initial CDC definitional committee."

"Conclusions: Definitions are not diseases, they are often simply the best descriptions that physicians and researchers can offer, with their always imperfect knowledge, to describe a disease. Good definitions are good because they correspond closely to the disease state being described. It is thus important that those that attempt to define any disease or illness to have long term clinical experience with patients with this illness. There is simply no place for the bureaucrat in defining illness. All definition of epidemic or infectious illness must be based upon persistent clinical examination of the afflicted patient, an understanding and exploration of the environmental factors producing that illness, and pathophysiological examination of tissue from those patients. For similar reasons, I believe that the inclusion of psychiatrists in the defining of an epidemic and obviously disease of infectious origin, simply muddies the water for any serious understanding of that disease. The UK definition of CFS was developed by a panel of physicians who were primarily psychiatrists, with few if any clinicians who had ever looked at an epidemic of CFS. A serious attempt must be made to look at epidemic disease as and where that disease starts. This has not been done by those who have defined CFS in the USA nor in the United Kingdom and this factor alone is probably the single greatest reason why we know so little about CFS today that we did not know in 1984."

[Note: The bold in this text has been added for emphasis by the editors.]

A New and Simple Definition of Myalgic Encephalomyelitis
and a New Simple Definition of Chronic Fatigue Syndrome
A Brief History of Myalgic Encephalomyelitis
& An Irreverent History of Chronic Fatigue Syndrome

Invest in ME prepared this abridged version of Dr. Hyde's "little red booklet" he presented at the 2006 IiME Conference.  An excellent brief summary for both doctors and patients.

Of note to Americans, in Dr. Hyde's textbook is a compilation of M.E. epidemics (Chapter 16).  Included in this chapter are some of the mid-1980s through early-1990s epidemics in the U.S.:  Incline Village, NV; Chapel Hill, NC; Truckee, CA; Lyndonville, NY; Yerington, NV; Placerville, CA; Sonora, CA; Roseville, CA; Elkgrove, CA.  Given Dr. Hyde's clear distinction between M.E. and CFS, the illness seen in these epidemics clearly was M.E., not the newly-devised "CFS" of that time.



Definitions Overview
ICC - Consensus Criteria
Canadian Consensus
Dr. Byron Hyde
Historic ME
Dr. A. Melvin Ramsay
Dr. E.G. Dowsett
Prof. Malcolm Hooper
ME/cfs Australia
Pediatric ME & cfs

Read excerpts from:

Are Myalgic Encephalomyelitis and Chronic Fatigue Syndrome
Synonymous Terms?

by Dr. Byron Hyde

"The primary diagnostic criterion for ME is acquired CNS change.  We have excellent tools for measuring these physiological and neuropsychological changes:
SPECT, xenon SPECT, PET and neuropsychological testing.
CFS patients may not have any of these findings...."
-Dr. Byron Hyde-

"Many patients with a diagnosis of CFS today have non-diagnosed major diseases.  These patients warp any statistical or scientific examination of the CFS patient.  Most of the patients I have seen from Canada, the United States, or from the United Kingdom with gradual onset CFS illness have non-diagnosed major medical illness or anomaly."
-Dr. Byron Hyde

View Dr Hyde's
The Complexities of Diagnosis

"Though the symptoms of CFS resemble those of ME, the differences are so significant that they would exclude ME patients from the 1988 and 1994 CDC diagnoses of CFS.  The following features of ME separate it from CFS:

● The epidemic characteristics.

● The known incubation period.

● The acute onset.

● The associated organ pathology, particularly cardiac.

● Infrequent deaths with pathological CNS changes.

● Neurological signs in the acute and sometimes chronic phases.

● The specific involvement of the autonomic nervous system.

● The frequent subnormal patient temperature.

● The fact that chronic fatigue is not an essential characteristic of the chronic phase of ME."

-Dr. Byron Hyde

Handbook of Chronic Fatigue Syndrome

"Myalgic Encephalomyelitis is not depression.
Myalgic Encephalomyelitis is not hysteria.
Myalgic Encephalomyelitis is not a conversion disorder nor is it a somatization disorder.
Myalgic Encephalomyelitis is an acute onset diffuse injury of the brain. Psychiatrists should not ever be placed in charge of diagnosis and treatment of M.E. patients. It is simply not their area of expertise and their meddling has at times caused great harm to
M.E. patients. "
-Dr. Byron Hyde-

"Do not for one minute believe that CFS is simply another name for Myalgic Encephalomyelitis (M.E.).  It is not.  Though CFS is based upon a typical M.E. epidemic, in my opinion it has always been a confused and distorted view of reality.
The invention of Chronic Fatigue Syndrome has to be one of the most curious cases of inventive American imperialism that one could imagine."
-Dr. Byron Hyde -
A New and Simple Definition of Myalgic Encephalomyelitis
and a New Simple Definition of Chronic Fatigue Syndrome
A Brief History of Myalgic Encephalomyelitis
& An Irreverent History of Chronic Fatigue Syndrome

Americans Should Shake Up the CDC Definition and Research Committees

by Byron Hyde M.D.

Excerpt:  Have you ever reviewed the physicians and researchers on the original 1988 CDC definition and counted how many of them actually had ever seen a significant number of CFS patients or had ever previously or after published on CFS? The number is not high. This improved in the 1994 definition committee but even then you may recall that this occurred only when I got up and criticized the chair for even attempting to put out another definition without a group of hands-on US and international physicians on the committee. I think that got Dan Peterson on the list. Unfortunately the 94 definition was a rubber stamp of the 88 definition that has plagued physicians ever since. There were still too many members on that committee who simply rubber-stamped the previous groupís work.

Name all of the serious original contributors to CFS knowledge in the past fifteen years and you may note the fact that their names are largely absent from the roster of NIH grant recipients.

Find me a single penny of NIH funds that has gone to autopsy research and tell me how many thousands of M.E./CFS patients who have died during this period, their brains and spinal cords lost to serious research.

Find me any serious ongoing funds dedicated by the NIH to any of the epidemic M.E./CFS situations that have occurred during the same period. Why were the strong epidemic features of M.E./CFS literally written out of the CDC definitions along with the known incubation periods of these epidemic illnesses at 4-6 days? Is it because this incubation period conflicts with EBV and HHV6 herpes virus incubation periods? You will recall that the incubation period of HHV6 is 12-14 days and that of EBV is roughly 40 days.

You asked me if you could reprint this information or circulate it. Yes you may. If anyone else is reprinting this letter, please include our website address and this paragraph and note that Nightingale is named after Florence Nightingale who fell ill with an illness that appears identical to acute onset M.E. /CFS. Also note that we are a charity that is operated by volunteers and we would just love a Christmas or Hanukkah or any charitable donation. Also mention our textbook,
The Clinical and Scientific Basis of M.E. /CFS

of which you speak so highly and which is available inexpensively at our website. Simply reprint this paragraph with your circulation.

Byron Hyde M.D.
Nightingale Research Foundation
Ottawa Canada

About Dr. Byron Hyde

Online Medical Dictionary


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