Fibromyalgia Triggering Events
Although no definitive cause(s) of fibromyalgia is known, substantial anecdotal evidence exists from fibromyalgia patients to suggest that a particular negative event, or trigger, immediately preceded or initiated their fibromyalgia symptoms. The current prevailing understanding of fibromyalgia is that it results from a phenomenon known as central sensitization, which simply means that the nervous system becomes impaired and unable to process pain signals appropriately. Researchers have explored a number of possible factors and conditions that might trigger the nervous system to malfunction. The most frequently documented and researched triggers include infection, physical trauma, and severe emotional stress.
Gaining an understanding of potential fibromyalgia triggers is important to patients for a number of reasons. First, identifying potential environmental triggers may help researchers determine methods to prevent exposure, such as new vaccinations or improved environmental hygiene. Second, understanding how triggers either cause or perpetuate fibromyalgia symptoms can provide valuable insight to patients and their care providers, and allow for better informed decisions for how to manage fibromyalgia symptoms. Finally, discovering the triggers associated with fibromyalgia may lead to substantial gains from a therapeutic standpoint. As research evolves and provides a better understanding of potential triggers, it can lead to the development of new therapies for treating fibromyalgia symptoms. Consider the following example. Although no concrete scientific evidence exists to definitively link a particular viral infection with the onset of fibromyalgia, if such a link is ever established, certain antiviral therapies may prove to be of use in alleviating the symptoms of fibromyalgia. Furthermore, vaccinations targeting the virus could be developed to prevent infection and curb the incidence of fibromyalgia due to exposure to that particular virus.
A recent review article evaluated the existing evidence regarding the potential role of vaccinations and infections in the onset of widespread pain and, more specifically, fibromyalgia. The authors concluded that no concrete evidence exists to link any particular infection or vaccination with fibromyalgia. The authors did note, however, that a higher prevalence of fibromyalgia and chronic pain has been found among individuals with a history of Lyme disease, HIV infection, and hepatitis C virus (HCV) infection, as well as mixed findings among patients with Parvovirus B19 (Cassisi et al., 2011). These findings are supported by prior research studies (Buchwald et al., 1996; Berg et al., 1993; Narvaez et al., 2005). In addition, anecdotal evidence from fibromyalgia patients and their physicians has long suggested a temporal association between infection and the onset of fibromyalgia symptoms. An Internet survey conducted by Bennett et al. (2007) found that out of 2,596 fibromyalgia patients, 26.7% of those who associated a specific trigger with the onset of their fibromyalgia symptoms referenced an acute illness. In the same survey, 43% of patients also indicated that infections caused their fibromyalgia symptoms to worsen.
Hepatitis C Virus and Fibromyalgia
Several studies have found an increased prevalence of HCV among fibromyalgia patients. Rivera et al. (1997) evaluated 112 fibromyalgia patients and 112 control subjects diagnosed with rheumatoid arthritis to determine the prevalence of HCV infection. In addition, the researchers also evaluated 58 patients with chronic hepatitis C due to hepatitis C virus infection for symptoms of fibromyalgia. The study found evidence of active HCV infection in 15.2% of the fibromyalgia patients versus only 5.3% of the control patients. Furthermore, many of these individuals showed normal liver function, which is uncharacteristic of HCV infection. Out of the 58 patients with hepatitis C, six were determined to meet the diagnostic criteria for fibromyalgia while another 13 (22%) had widespread musculoskeletal pain. In their discussion of the findings, the authors state that their data support an association between fibromyalgia and active HCV infection, and that from a treatment perspective, presence of virus should be considered during the diagnosis of fibromyalgia even when liver function appears normal (Rivera et al., 1997). Other researchers have reached similar conclusions. Buskila et al. (1997) also found a 16% prevalence of fibromyalgia among individuals with HCV infection, and noted the importance of recognizing the existence of fibromyalgia among individuals with HCV in order to properly treat the symptoms.
However, not all studies have found an association between HCV infection and fibromyalgia. A more recent study conducted by Palazzi and colleagues sought to determined the prevalence of HCV infection among 152 Italian patients with fibromyalgia and 152 age- and sex-matched control subjects with either osteoarthritis or lumbar disc hernia-related sciatica. The study found only a 4.6% prevalence of HCV infection among the fibromyalgia patients and a 3.3% HCV infection among controls. In their discussion, the authors note the scarcity of evidence to support a causal link between HCV infection and the onset of fibromyalgia, and point to other studies that have found a similarly low prevalence of the infection among fibromyalgia patients (Narvaez et al., 2005). However, the authors note that their findings may not be applicable to other geographic locations where HCV is more common (Palazzi et al., 2008).
Parvovirus B19 and Fibromyalgia
In addition to HCV, other viruses have been investigated, albeit less extensively, to determine their role in fibromyalgia. Parvovirus B19 is the virus responsible for causing the condition known as fifth disease, or erythema infectiosum. Parvovirus B19 spread through saliva and nasal mucus when an individual sneezes. It can also spread through blood or blood products, and can be passed from mother to baby during pregnancy. It is characterized by a mild rash and most often occurs in children. Individuals who become infected with the virus typically become symptomatic within 14 days following infection, and up to 20% of those who are infected will never display any symptoms. The most common symptoms of fifth disease are nonspecific and common to many other ailments. They include fever, runny nose, headache, and they typically occur before the characteristic rash presents. The rash may itch, may vary in intensity, and may appear and disappear periodically over the course of several weeks. Adults who develop fifth disease – in particularly women – may experience pain and swelling in their joints without any other symptoms. Although this pain can last for weeks to months, it usually subsides with no long-term side effects. No vaccines or specific treatments are available for fifth disease, and it usually resolves on its own.
Evidence of parvovirus B19 infection is relatively common among adults and detectible levels of antibodies (specific immune system cells that fight infection) increases with age (Berg et al., 1993; Meyer, 2003). Furthermore, women experience higher rates of infection than men. In addition, parvovirus B19 infection has been linked to a number of rheumatic diseases. As a result of this collective evidence, several studies have examined the presence of antibodies to parvovirus B19 in individuals with fibromyalgia in an effort to determine if it could be considered a trigger for the condition. The scientific literature contains reports of several patients who developed fibromyalgia-like symptoms following documented infection with parvovirus B19 (Leventhal et al., 1991). However, some studies have failed to show a definitive relationship between increased rates of parvovirus B19 infection among fibromyalgia patients when compared to healthy controls (Berg et al., 1993; Narvaez et al., 2005).
Nevertheless, a more recent study by Buyukkose et al. (2009) showed promising results. The authors evaluated 75 fibromyalgia patients (71 female, 4 male) and 75 healthy controls (71 female, 4 male) for antibodies to parvovirus B19. Two parvovirus antibodies were measured in this study – anti-B19 IgG antibodies (which indicate a history of prior infection) and anti-B19 IgM antibodies (which indicate a history of recent infection). The researchers found statistically higher levels of IgG in patients with fibromyalgia than in controls (81.3% vs. 64%, respectively). No significant differences were detected between cases and controls with regard to IgM levels. In their discussion, the authors suggest that parvovirus B19 infection may be involved in the development of fibromyalgia, or may act as a trigger for fibromyalgia-related symptoms. The authors briefly discuss the biologic rationale for the role of infections in triggering fibromyalgia symptoms, however at the same time, they note the inherent difficulties in studying the potential role of parvovirus B19 in fibromyalgia due to its widespread prevalence in the general population (Buyukkose et al., 2009).
Severe Emotional Stress, Trauma, and Fibromyalgia
In addition to infection, fibromyalgia patients also frequently report that a severely stressful event, such as the loss of a loved one, or an intense physical trauma such as a car accident, immediately preceded the onset of their symptoms (Buskila & Neumann, 2000; Greenfield et al., 1992; Waylonis & Perkins, 1994). This has led to considerable research into traumatic events – both physically and emotionally – that may in fact trigger fibromyalgia. Although some studies have found no association between physical traumas such as motor vehicle accidents or whiplash in the onset or perpetuation of fibromyalgia symptoms (Tishler et al., 2011; Tishler et al., 2006; Wynne-Jones et al., 2006; Holm et al., 2007), others have found significant associations.
In an effort to explain how physical and emotional stress or trauma may trigger the onset of fibromyalgia, recent research suggests that the chronic widespread pain that characterizes fibromyalgia may in fact result from a whole-body response to stress (Lyon et al., 2011). Other theories are built on a similar hypothesis and suggest that severe emotional and physical stressors may result in alterations in the way the central nervous system responds to stress. In the body, the autonomic nervous system controls involuntary muscle movements and functions of the internal organs, such as heartbeat and the process of digestion. There are two divisions of the autonomic nervous system: the sympathetic nervous system, and the parasympathetic nervous system. While the parasympathetic nervous system operates during times of relaxation, the sympathetic nervous system is responsible for the body’s fight-or-flight response, which is activated during times of stress. Recent theories in fibromyalgia research suggest that fibromyalgia may result from a hyperactive sympathetic nervous system, or sustained fight-or-flight reaction (Martinez-Lavin, 2012). This hypothesis is supported by the reports from fibromyalgia patients who associate a traumatic or emotionally stressful event with the onset of their symptoms (Boisset-Pioro et al., 1995; Jones et al., 2011; Buskila et al., 1997), as well as various biochemical and neurological observations previously documented by researchers (Martinez-Lavin, 2007; Martinez-Lavin et al., 2002).
In 1997, Buskila and colleagues evaluated 102 patients with cervical spinal injuries and a control group of 59 patients with leg fractures. They assessed tender points and the presence and severity of both neck- and fibromyalgia-related symptoms. Using the 1990 American College of Rheumatology criteria, 21.6% (22) patients with cervical spinal injuries were found to develop fibromyalgia following their injury, versus only 1.7% of those with lower leg fractures. Symptom severity was greater and quality of life was worse among those with neck injuries (Buskila et al., 1997). In a follow-up study conducted by Buskila and colleagues in 1999, 20 of the original patients diagnosed with fibromyalgia following cervical spinal injury were re-evaluated. The follow-up study found that 60% of those patients still had clinically significant fibromyalgia. Those whose fibromyalgia failed to meet the diagnostic criteria during the 1999 re-evaluation were all men. The authors note the small sample size in their study, however, and point to the need to interpret their findings with caution (Neumann et al., 2003).
Other studies have shown an association between being in a road traffic accident and the development of chronic widespread pain. Jones et al. (2011) found that out of 2,069 individuals who were followed over a four-year period, nearly 12% developed chronic widespread pain and one-third experienced at least one physically traumatic event. The researchers found that only road traffic accidents were significantly related to the onset of widespread pain, and in their discussion of the findings, pointed to the need for future research to determine what peculiarities exist in relation to an accident that increases an individual’s risk of developing chronic widespread pain. The authors also suggest that a certain subset of individuals may be predisposed to the development of widespread pain following a traumatic triggering event, as a result of poorer overall health status and certain psychological characteristics (Jones et al., 2011).
In addition to physical trauma, severe emotional stress and early life exposures have also been investigated for their role as potential fibromyalgia triggers. Interesting evidence has recently emerged to suggest that premature birth and neonatal exposure to pain may alter the early development of the body’s ability to process pain, thereby increasing the risk of fibromyalgia later in life (Low & Schweinhardt, 2012). In addition, self-reported childhood maltreatment, including emotional and sexual abuse, have also been associated with chronic pain in women (Nicolson et al., 2010) and also suggest that early childhood exposures may predispose to malfunctioning pain processing in adults (Weissbecker et al., 2006). Some studies, however, have found little to no association between sexual and physical abuse among adult women and the onset of fibromyalgia symptoms (Ciccone et al., 2005), whereas others have determined a strong association (Walker et al., 1997). It is important to note, however, that many studies have been conducted using small numbers of fibromyalgia patients and have relied on self-reported incidence of physical, emotional and sexual abuse.
Indirectly supporting all of these findings are results from other studies that have demonstrated associations between either a single stressful event, or cumulative stress, on the severity and quality of life among fibromyalgia patients (Dell’Osso et al., 2011).