American College of Physicians: Internal Medicine — Doctors for Adults ®

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Monday, March 8, 2010

Is Chronic Fatigue Syndrome Caused By Retroviruses?

This post by Harriet Hall, MD, originally appeared at Better Health.

When I first heard that a retrovirus had been identified as a possible cause of chronic fatigue syndrome, I withheld judgment and awaited further developments. When I heard that two subsequent studies had failed to replicate the findings of the first, I assumed that the first had been a false alarm and would be disregarded. Not so.

It's a classic case of wishful thinking outweighing good judgment. One unconfirmed report of an association between the XMRV virus and chronic fatigue syndrome (CFS) resulted in a rush to test for the virus, speculation about possible implications, and even suggestions for treatment. And the subsequent negative studies did little or nothing to reverse the trend.

XMRV is Xenotropic murine leukemia virus-related virus. In the past, there were reports that this retrovirus was associated with prostate cancer, but then other reports found no link. In 2009 a study was published in Science, Detection of an Infectious Retrovirus, XMRV, in Blood Cells of Patients with Chronic Fatigue Syndrome by Lombardi et al., reporting an association with CFS:

We identified DNA from a human gammaretrovirus, xenotropic murine leukemia virus-related virus (XMRV), in 68 of 101 patients (67%) as compared to 8 of 218 (3.7%) healthy controls.

Later, the researchers reported that up to 95% of CFS patients test positive with antibody testing. The study did not prove a causal relationship. The authors suggest that the retrovirus may reactivate other viruses, such as herpes viruses (the opposite is also possible). There could be many different viruses behind CFS/ME. And it could be that XMRV is an incidental finding secondary to the immune dysfunction in CFS/ME. Two subsequent studies in the UK, here and here, also looked for the virus in CFS patients but both failed to find it.

CFS is still a controversial diagnosis. Some observers have implicated psychological factors and somatization. Sufferers are on the defensive, wanting to validate CFS as a real physical entity. The finding of a virus was just what they were hoping for. They want to believe in it, and their emotions have clouded their judgment.

A battle has erupted between retrovirus believers and non-believers, each side attacking the other's research and accusing them of bias. Some of the criticisms are based on virological laboratory procedural details that I am not competent to judge. Some of the other criticisms are about things I can understand.

The Science study came out of the The Whittemore-Peterson Institute. This institute was founded by a couple (the Whittemores) whose daughter had CFS and who was treated by Dr. Peterson with an experimental antiviral drug. They are clearly biased towards finding a viral etiology. The researchers in the UK were similarly accused of bias towards finding a psychological etiology. Accusations of bias may be credible but don't necessarily mean that the bias contaminated the results. Another criticism is less credible: the UK studies used a different set of criteria for diagnosing CFS. Even if you think that some of the UK subjects didn't qualify as having CFS, if even a few of them had CFS and the virus was really associated with it, the virus should have shown up in at least a few subjects. Critics have tried to rationalize away the negative findings in the UK by suggesting that the virus occurs regionally and is absent in the UK; but then if the virus were the cause of CFS, there wouldn't be any CFS in the UK.

So far we have one study for and two against the association of XMRV with CFS. More studies are underway that should settle the debate. If the virus is there, it will be found by other labs and a consensus will eventually develop as to whether there is an association. If an association is confirmed, there will still need to be further research to determine what the association means and whether there is a causal relationship. The logical response is to stay tuned, not to leap prematurely into testing and treatment.

Tests are already commercially available. One is offered by VIP Diagnostics, a company owned by the Whittemore family. It costs $450 and uses the same methods as were reported in the Science article. The website discloses that the tests have not been approved by FDA for diagnostic purposes and that medical expertise is required for test interpretation. The lab pays a royalty to the Whittemore-Peterson Institute for each test it performs.

In his Nov. 3, 2009 Lyndonville Times newsletter, Dr. David Bell offered this cogent advice: "I am reluctant to suggest to anyone that they spend big bucks for a commercial test now. We do not know if a particular test is accurate, and even if it is accurate we do not know what it means, and even if we did know what it meant we would not know what to do with it."

That pretty much says it all. Nevertheless, patients are flocking to be tested. If they test positive, they can feel vindicated. If they test negative, they can rationalize that they may actually be positive but have a viral load too small to be picked up on the test at the moment; they might even rationalize that they are better off than if the test had shown a larger viral load. Win/win.

Antiretroviral treatments are already being proposed by some doctors. Most proposals are based on the drugs used for HIV/AIDS, on the assumption that antiretroviral AIDS drugs would be equally effective for the XMRV retrovirus. But that might well be a false assumption, and these are powerful drugs with worrisome side effects, not the sort of thing that you would want to try "just in case."

Other concerns have been raised by the CFS community. Is XMRV sexually transmitted like HIV/AIDS? If you have chronic fatigue syndrome or another XMRV-related condition, should you take special precautions with your sexual partners, even if you're in a committed relationship? Should you opt for not breastfeeding your children? Should you not even have children?

I can understand the desperation of these patients. I can understand their need to believe anything that would validate their suffering. I can understand their motivation to try anything that might bring them relief. But I don't want to see people wasting money on useless tests, I don't want to see mothers unnecessarily worrying about whether it is safe to breastfeed their children, and I don't want to see people suffering side effects from drugs they don't need. A cautious wait-and-see approach is dictated by common sense and by an understanding of how often initial scientific research findings turn out not to be true. Like remarriage after divorce, the overblown enthusiasm for the XMRV/CFS connection is a triumph of hope over experience.

This post originally appeared on Better Health, a network of popular health bloggers brought together by Val Jones, MD. Better Health's mission is to support and promote health care professional bloggers, provide insightful and trustworthy health commentary, and help to inform health policy makers about the provider point of view on health care reform, science, research and patient care.

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Blog log

Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Auscultation
Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Richmond, Va., with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

DrDialogue
Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

Everything Health
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

FutureDocs
Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

I'm dok
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

Just Oncology
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.

KevinMD
Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.

MD Whistleblower
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

More Musings
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).

Prescriptions
David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.

Reflections of a Grady Doctor
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.

PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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