by Dr. Mark J. Pellegrino, MD
Excerpted from the book, Fibromyalgia: Up Close and Personal


January 2010 



All of us involved with Fibromyalgia, either by treating it or having it, have come to appreciate how complicated this condition is.

Fibromyalgia has different types and subsets. More than one factor may be involved in causing it. Causes may be recognized, but the exact mechanism of how Fibromyalgia develops from this cause is not fully known. Most importantly, there is more than one way to get Fibromyalgia; it is an “end point” condition with multiple ways leading to it.

I have compiled a list of probable causes of fibromyalgia. This list is based on my experiences and understanding of the current literature. My opinions on these probable causes may not be shared by everyone. My list of probable causes is as follows:

  1. Genetics
  2. Trauma
  3. Connective tissue disease
  4. Infection
  5. Catastrophic stress
  6. Chemical exposure

Like trauma, infection is one of those causes of fibromyalgia that just screams for common sense.

I’ve seen hundreds and hundreds of people whose basic story goes like this: “I was fine, I got a virus, I developed fatigue and pain, and I’ve never been the same since.”

The logical thinking in this scenario is that fibromyalgia was not present before the viral infection. There may have been a hereditary predisposition or a vulnerability, but fibromyalgia was not present. The virus caused the condition to develop and it has been present since the virus and continues to be present. This is a straightforward infectious cause.



Not all infections are as straightforward.

Many people who have fibromyalgia get a viral infection and find it worsens the fibromyalgia. People with active viral infections are at risk for additional infections, particularly bacterial infections which can create additional problems.

Some people with fibromyalgia are more vulnerable to any type of infection because the fibromyalgia renders them more immunocompromised or more at risk for infection. The physician needs to sort out the various possibilities to determine whether an infection is the cause, a consequence, or an aggravator of the fibromyalgia.

The mechanism by which an infection leads to fibromyalgia is probably related to inflammatory or autoimmune changes caused by the infection that starts the fibromyalgia cascade. The actual clinical infection resolves and is long gone, yet fibromyalgia symptoms continue.

Sometimes, the infecting virus or bacteria may hang around and create a persistent low grade infection which activates the autoimmune responses, thereby “triggering” the fibromyalgia.

Many times, though, the infection has long disappeared, but permanent changes occurred in the body, and these changes caused fibromyalgia to develop.




Various viral infections can cause fibromyalgia

  • The Epstein-Barr virus which causes infectious mononucleosis is one.
  • Cytomegalovirus causes a syndrome similar to infectious mononucleosis.
  • Different strains of the influenza virus can also result in fibromyalglia.
  • The adenoviruses, especially Type II, cause common colds, bronchitis, and various upper respiratory infections, and may lead to fibromyalgia.
  • Human Herpes Virus 6 has also been implicated.
  • Reactive fibromyalgia has been described in patients with AIDS and hepatitis.

Sometimes viral titers can be directly measured to demonstrate that an acute infection has occurred. This concentration can be correlated with the clinical development of fibromyalgia. Many times, though, the exact offending virus is not known, but we can still categorize the fibromyalgia as one that was caused by an infection, probably a viral infection, if it fits clinically.

Bacterial infections can also cause fibromyalgia

I have seen patients who have developed fibromyalgia after sepsis (blood infection) and salmonella infections, and one who, I felt, has gotten it from a Listeria infection. Some research studies found Mycoplasma incognitos and Chlamydia pneumoniae in patients with fibromyalgia and chronic fatigue syndrome. These infectious organisms may be causing some of the symptoms.

Indeed, some of the patients improve with antibiotic therapy. Gulf War Syndrome, in part, may have been related to infections from one of these bacteria. Symptoms of Gulf War Syndrome include fatigue, headaches, depression, joint and muscle pain, sleep disorders, and poor memory (sound familiar?). [Note: As of November 2008, a research panel reported their finding that Gulf War illness is real, and “is the result of neurotoxic exposures,” as discussed in Chapter 10 under Chemical Exposure as a probable cause of FM.]

Fibromyalgia can be caused by yeast and parasite infections

I have seen some patients who developed it following a severe Candida yeast infection, and others following parasite infections such as Giardia. Most of the time, yeast or parasite infections occur in patients after the fibromyalgia has already developed. These infections may aggravate the preexisting fibromyalgia or cause it to flare up.

Fibromyalgia may predispose us to these infections by interfering with our immune function. On the other hand, these infections can sometimes cause the fibromyalgia by “triggering” the fibromyalgia cascade. Many of the symptoms of a chronic Candida yeast infection - such as fatigue, irritable bowel syndrome, bloating, allergies, altered immune response, and skin conditions - overlap with fibromyalgia symptoms. This can make it difficult to “separate” the two conditions and determine cause and effect relationships.

As I’ve mentioned, some infections come in, do their damage and disappear. The infectious agent is no longer present in the body and thus can’t be detected at a later point in time. Other infectious agents may hang around in the body and establish a chronic infection; one that perhaps can be detected with blood tests.

What remains to be seen is whether these chronic infections can be eradicated with antibiotic treatment and, if so, will the fibromyalgia symptoms disappear? Or has the fibromyalgia already established itself as a separate entity which does not disappear with the antibiotic treatment?

Hopefully we will have these answers in the near future. [But]… one thing is certain: We will continue to learn more about fibromyalgia and understand it better.



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Dr. Pellegrino has seen more than 20,000 FM patients in his practice at the Ohio Rehab Center, and has been a fibromyalgia patient himself since childhood.



Read more in Fibromyalgia: Up Close and Personal:



Fibromyalgia: Up Close and Personal