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Myalgic Encephalomyelitis

I believe it essential to define clearly Myalgic Encephalomyelitis, returning the definition to its clinical and historic roots and complementing this information with the certitude of modern scientific testing. That is what the Nightingale definition of M.E. sets out to do.   Byron Hyde

A new and simple definition of Myalgic Encephalomyelitis

Myalgic Encephalomyelitis is:

  • 1  A variable and biphasic acute onset disease,
  • 2  Primary Infection Phase: The first phase is an epidemic or endemic infectious disease generally with an incubation period of 4 to 7 days, where in most, but not all cases, an infection is evident.
  • 3  Chronic Phase: The second and chronic phase follows closely on the first phase, usually within two to seven days, and is characterized by a measurable diffuse change in the function of the CNS. This is the persisting disease that most characterizes M.E. and is demonstrated by the following:
  • 4  Testable Brain Changes: This second phase becomes chronic and is characterized by various measurable and clinical dysfunctions of the cortical or cortical and sub cortical brain. If the patient's illness is not persistently measurable using SPECT, PET or QEEG and/or Neuropsychological changes then it is not M.E. These changes can be roughly characterized as to severity:
    1. Type 1: where one side of the cortex is involved. These patients have the best chance of spontaneous recovery.
    2. Type 2: where both sides of the cortex are involved: These patients have the least chance of spontaneous recovery.
    3. Type 3: where both sides of the cortex, and either one or all of the posterior chamber organs, the Pons and Cerebellum, the sub cortical and brain stem structures are involved. Type 3 are the most severely affected patients and the most likely to be progressive or see little or no improvement with time.
  • 5  Pain Syndromes: The pain syndromes associated with the acute and chronic phases of M.E. may include (a) severe headaches of a type never previously experienced, (b) often associated with neck rigidity and occipital pain, (c) retro-orbital eye pain, (d) migratory muscle and arthralgia pain, (e) cutaneous hypersensitivity and (f) fibromyalgia type pain. These pain syndromes tend to decrease over time.
  • 6  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. This feature may improve over a period of years in patients with adequate financial and social support.
  • 7  Major Sleep Dysfunction: including all forms of sleep dysfunction and day time alertness and sleep reversals.
  • 8  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 years.
  • 9  Vascular Dysfunction: This is the most obvious dysfunction when looked for and probably is the cause behind a significant number of the above complaints. Vascular change is most evident in patients with:
    1. POTS: severe postural hypotension.
    2. Cardiac irregularity: on minor positional changes or after minor physical activity, including inability for the heart to increase or decrease in speed and pump volume in response to increase or decrease in physical activity.
    3. Raynaud's Disease: vasoconstriction, blanching, coldness and pain of extremities. This is in part the cause for temperature dysfunctions seen in M.E.
    4. Bowel Dysfunction: vascular dysfunction may be the single most causal basis behind bowel dysfunction when it occurs
  • 10  Endocrine Dysfunction: This feature is common and tends to be a late appearance and is most obvious in the:
    1. Pituitary-thyroid axis: This is common. Changes in serum TSH, FTI, FT4, Microsomal Ab., PTH, Calcium and phosphorus rarely occur until one or more years after illness onset and usually only after several years. This can be followed by ultrasound of the thyroid gland where a steady shrinking of the thyroid gland occurs with or without the development of non-serum positive Hashimoto's thyroiditis (a seeming contradiction of terms) and a significant increase in thyroid malignancy. Serum positive changes occur only after years.
    2. Pituitary-adrenal axis changes: this finding is infrequent.
    3. Pituitary-ovarian axis changes:
    4. Pituitary- (adrenal?)-Bladder dysfunction: occurs frequently in the early disease in some people. It is unknown if the cause is due to this link.


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