Chronic Fatigue Syndrome: a Legitimate Excuse for Missing Work

Student guest post by Jay Watson

Tired again? Perhaps it’s the crappy weather, because you’re sure that you’ve been getting enough sleep. After all, you can’t remember the last time you spent less than ten hours in bed per night. Hopefully it’s not mono; one of your friends had it a few months ago and it’s all but knocked her out. However, you soon realize that you’ve only talked to her on the phone since she got engaged, so there’s no way that’s it. It’s strange, even everyday activities like running errands has turned into something utterly exhausting. As you consider the reasons as to why you’ve felt so drained for… well for as long as you can remember, you whittle your way down through all the likely suspects. Worried, you finally make a trip into the doctor’s office. After seeing a couple doctors and explaining your medial history in depth each time, a specialist eventually mentions that you might be suffering from chronic fatigue syndrome.

According to the CDC, Chronic fatigue syndrome (or CFS) is a complex disorder that is characterized by severe chronic fatigue that lasts at least six months, as well as at least four of the following symptoms: impairment of short-term memory or concentration, sore throat, tenderness in lymph nodes, muscle or joint pain without swelling or redness, headaches, unrefreshing sleep, and post exertional malaise. In addition to the symptoms listed above, patients diagnosed with CFS have noted several other commonly observed symptoms. Because the laundry list of symptoms can be long, and due to the fact that ‘fatigue’ itself accompanies numerous other illnesses, diagnosis can only be made after eliminating other causes. Diagnosis includes more than one specialist, which typically involves detailed physical examinations and medical histories. Also, it is important to note that there is no laboratory technique currently available to test for chronic fatigue syndrome. Treatment for CSF focuses on the symptoms experienced by individual patients. Though there are plenty of gaps in the knowledge base for this disease, what is known is that CSF affects over one million Americans, and it occurs four times more frequently in women than men. Worldwide, CSF is estimated to affect 17 million, with a majority of people still undiagnosed. Also, CSF is a disease associated with adulthood, with people between forty and fifty most likely to have it. However, true to its name, the specific cause for this syndrome has not been established… yet!

Recently, actually very recently in fact, there has been much attention diverted to a potential factor involved with CSF: Xenotropic murine leukemia virus-related virus (or XMRV for short). Also according to the CDC, this virus is similar to a known mouse retrovirus. However, beyond knowledge of XMRV at the molecular level, little is known about the virus and its mode(s) of transmission. Even the CDC admits that the manner in which XMRV is transmitted is still uncertain and that more information is needed. Initially thought to be only associated with human prostate cancer, a study done by Vincent Lombardi and colleagues in October of 2009 found that approximately 67% of cases in the study diagnosed with CSF had detectible levels of XMRV versus about 4% of controls. Very quickly, additional studies to test this hypothesis have arisen. In contrast with Lombardi’s results, none of the subsequent studies have found an association between XMRV and chronic fatigue syndrome, including a both a case control study and a cohort study in the UK and a small cohort study done in the Netherlands. However, research is so incomplete regarding the association between these two factors that currently researches do not have the ability to say things are one way or the other.

Regardless of the complexity of CSF and the novelty of XMRV, research has undoubtedly unveiled some very important implications that I conclude with:

• Is/will there ever be a method developed so that we can prevent chronic fatigue syndrome rather than treat the symptoms of it alone?

• Why are women more likely than men to have it? What other epidemiologic factors play into CFS?

• Is there significant evidence to associate XMRV with CSF? How much is enough?

• What about XMRV and prostate cancer, as initially theorized?

• Is XMRV actually infectious? How is it transmitted? How virulent is it?

• If XMRV actually is a cause, or at least a within the causal pathway of CFS, what are some of the implications there? Would there be a cure? Can eventually eliminate chronic fatigue syndrome?

Obviously this is not an exhaustive list, but something worth pondering. Perhaps tomorrow’s research will lend insight into this intriguing disease and it’s mysterious cause(s).

References

Chronic Fatigue Syndrome. Center for Disease Control and Prevention. U.S. Department of Health and Human Services. Revised 5 May 2006.

Erlwein O, Kaye S, McClure MO, Weber J, Wills G, et al. 2010 Failure to Detect the Novel Retrovirus XMRV in Chronic Fatigue Syndrome. PLoS ONE. 5(1).

Groom HC, Boucherit VC, Makison K, Randal E, Baptista S, Hagan S, Gow JW, Mattes FM, Breurer J, Kerr JR, SToye JP, Bishop KN. 2010. Absence of xenotropic murine leukaemia virus-related virus in UK patients with chronic fatigue syndrome. Retrovirology. 7(10).

Infectious Mononucleosis. WebMD. Healthwise, Inc. Revised 8 September 2009.

van Kuppeveld FJM, de Jong AS, Lanke KH, Verhaegh GW, Melchers WJ, Swanink CMA, Bleijenberg G, Netea MG, Galama JMD, van der Meer JWM. 2010. Prevalence of xenotropic murine leukaemia virus-related virus in patients with chronic fatigue syndrome in the Netherlands: retrospective analysis of samples from an established cohort. British Medical Journal. 340(1018).

Lombardi VC, Ruscetti FW, Gupta JD, Pfost, MA, Hagen KS, Peterson DL, Ruscetti SK, Bagni RK, Petro-Sadowski R, Gold B, Dean M, Silverman RH, and Mikovits JA. 2009. Detection of an Infectious Retrovirus, XMRV, in Blood Cells of Patients with Chronic Fatigue Syndrome. Science. 326(5952): 585-589

Malaise. 2010. Merriam-Webster Dictonary Online.

Retrovirus. 2010. Merriam-Webster Dictonary Online.

Xenotropic Murine Leukemia Virus-related Virus (XMRV). Center for Disease Control and Prevention. U.S. Department of Health and Human Services. Revised 18 February 2010.