|Results from 51 completed surveys - 9/26/2010|
Eager to find answers to the question “What do people with XMRV (and associated human gamma retroviruses) have in common?” we looked at the results from the first 51 completed XMRV Positive Surveys. Of all the symptoms queried, post-exertional malaise (PEM) ranked the highest. A whopping 94% of respondents reported some degree of worsening of symptoms after increased physical or mental exertion.
We then looked at the particular symptoms associated with PEM as well as the time of onset and duration of those symptoms. In the charts above, we reported all symptoms that affected more than 50% of the respondents. Our data closely mirror those symptoms described in the ME/CFS: 2003 Canadian Clinical Case (CCC) Definition1.
The CCC was a great improvement over the CDC's 1994 Fukuda case definition for CFS. "The CDC definition, by singling out severe, prolonged fatigue as the sole major (compulsory) criterion, de-emphasized the importance of other cardinal symptoms, including post-exertional malaise (PEM), pain, sleep disturbances, and cognitive dysfunction."1 In contrast, PEM is a required symptom for the diagnosis of ME/CFS according to the CCC definition and is thus described:
The malaise that follows exertion is difficult to describe but is often reported to be similar to the generalized pain, discomfort and fatigue associated with the acute phase of influenza. Delayed malaise and fatigue may be associated with signs of immune activation: sore throat, lymph glandular tenderness and/or swelling, general malaise, increased pain or cognitive fog. Fatigue immediately following activity may also be associated with these signs of immune activation. Patients who develop ME/CFS often lose the natural antidepressant effect of exercise, feeling worse after exercise rather than better. Patients may have a drop in body temperature with exercise. Thus fatigue is correlated with other symptoms, often in a sequence that is unique to each patient. After relatively normal physical or intellectual exertion, a patient may take an inordinate amount of time to regain her/his pre-exertion level of function and competence. For example, a patient who has bought a few groceries may be too exhausted to unpack them until the next day. The reactive fatigue of post-exertional malaise or lack of endurance usually lasts 24 hours or more and is often associated with impairment of cognitive functions. There is often delayed reactivity following exertion, with the onset the next day, or even later. However, duration of symptoms also varies with the context. For example, patients who have already modified their activities to better coincide with the activity level they can handle without becoming overly fatigued will be expected to have a shorter recovery period than those who do not pace themselves adequately.1
1. Carruthers, B. M., Jain, A., De Meirleir, K. L., Peterson, D. L., Klimas, N. G., Lerner, A., et al. (2003). Myalgic Encephalomyelitis/Chronic Fatigue Syndrome -- Clinical Working Case Definition, Diagnostic and Treatment Protocols. Journal Of Chronic Fatigue Syndrome, 11(1), 7-115. doi:10.1300/J092v11n01_02
* Pathognomonic - A sign or symptom that is so characteristic of a disease that it makes the diagnosis. The word "pathognomonic" (pronounced patho-no-monic) comes from the Greek "pathognomonikos' meaning "skilled in judging diseases."