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What is the link between trauma and fibromyalgia?
[FIBROMYALGIA (FM) is a chronic condition characterised by widespread deep musculoskeletal pain accompanied by various other non-specific symptoms, including chronic fatigue, sleep and mood disturbances and cognitive problems. The condition is relatively common, occurring in around 2-8% of the adult population, and is much more common in women than in men.
For years the existence of FM was a controversial topic, but nowadays it is generally accepted as a real entity. However, there is still no available test to confirm diagnosis and the reporting of symptoms is entirely subjective. It has been suggested that in up to one third of cases FM may be triggered by previous traumatic events in the patient’s life, with the other two thirds occurring spontaneously.
Physical trauma, often in the form of an accident at work or a traffic collision, is commonly cited as a precipitating event for FM. However, it is difficult to prove causation, particularly where an incident has not caused any visible injury. Despite that, increased rates of FM following accidents have been widely reported. Studies in the UK, US and Israel have reported incidence rates of between 1% and 22% for FM or diffuse pain for individuals involved in car and train accidents.
Those rates appear much higher than would be expected in the general population, particularly in individuals in whom the original injury occurred in the neck. Furthermore, in one study an ‘at-risk’ group could be identified on the basis of poorer health and psychological variables. However, a study conducted in Lithuania, where disablement is both less common and less well compensated, found no cases of chronic neck pain following a motor vehicle accident.
Workplace injury is also often cited as a causal factor in FM. Prospective studies of new workers have reported that, 12 months after starting the job, rates of chronic widespread pain were as high as 15%. The majority of cases appear to be due to a single injury, with the lower back and shoulder being the most commonly cited areas of damage. However, generalised activities such as repetitive movements, lifting, pushing or pulling heavy weights, kneeling or squatting and working with the hands at or above shoulder height have also been claimed as triggering factors. Psychosocial factors, such as monotonous work and low social support, appear to increase the risk even further.
Psychological trauma and FM
As well as physical trauma, many studies have reported an increased prevalence of psychological trauma in FM patients. Adversity in early life appears to be particularly important. Factors such as being taken into care, the death of a parent, family financial hardship, emotional neglect and behavioural problems have all been linked to chronic widespread pain later in life, and those associations appear to be more marked in patients who are not concurrently suffering from depression. A clear gradient of increasing loss of function in participants with higher trauma scores, which again was seen more clearly in non-depressed individuals, has also been reported. Childhood abuse nearly doubles the risk of developing a chronic pain condition, including FM, in adulthood. However, a lifelong history of sexual abuse does not show an association with FM, suggesting that the timing of the trauma may be critical.
When taken as a whole, there does appear to be evidence of a link between trauma and the development of FM. A review of 51 studies found that the majority reported a significant association between physical or emotional trauma and the onset of chronic widespread pain or FM. The evidence appeared to be strongest for psychological trauma and FM, where the link was widely demonstrated. However, many of the studies on which this review was based provided data which was of low-quality, when assessed by GRADE criteria.
One major problem with most of the evidence regarding trauma and FM is that it comes from retrospective studies, which are reliant on the participants’ recollection of traumatic events. Patients who are suffering from a disease with no obvious cause may look for past events in an attempt to explain their condition. However, research shows that adult recall of adverse childhood experiences actually tends to underreport such events. That would tend to dilute any associations seen between trauma and FM.
Some adults do not report childhood trauma because they feel they have ‘moved on’ and no longer identify as a trauma survivor. Others will simply not remember events that happened in very early childhood. Individuals who continue to report trauma may have been more negatively affected by the event and thus more likely to experience greater pain-related disability in later life.
Another issue with retrospective studies, particularly those of a cross-sectional design, is that the temporal relationship between trauma and FM cannot always be established. A clear and logical time sequence is critical in trying to prove causality. Finally, physical trauma, such as a serious accident, is almost always accompanied by psychological sequelae and it is difficult to separate out the role that each plays in the causation of FM.
The mechanisms by which trauma leads to FM are not entirely clear. It has been suggested that certain aspects of physical work may result in centralised pain sensitivity. Traumatic experiences in early life may predispose to FM by excessively activating stress responses during a critical period of development, thus altering normal development and reactions to stress and painful stimuli through hyperalgesic priming. As the resulting pain is a stressor, it may lead to a positive feedback loop, which serves to increase anxiety levels and further impact on stress regulation.
Alteration of the stress response appears to be mediated via the hypothalamic-pituitary-adrenal axis, although the precise way that happens is not yet known. Trauma increases the responsiveness of the central nervous system due to decreased functional connectivity in the descending pain-modulating system and heightened sensory responses. Furthermore, childhood abuse has been linked to a disruption of normal diurnal cortisol levels – a hormone associated with stress – and that effect has also been observed in FM patients.
The observation that experiences in early life can lead to FM many decades later suggests that the neuroplastic changes associated with stress are part of a chronic process that develops slowly. It is also likely that the effects of traumatic events are mediated by the individual’s genetic predisposition and psychological status.
Treatments for FM
FM is a difficult condition to treat: pharmacological treatments are not effective for many patients. As a result, non-pharmacological interventions such as cognitive behavioural therapy (CBT) are often recommended, but frequently only lead to modest improvements in the patient’s condition.
Recently, research has examined the concept of customising treatment on the basis of psychosocial needs to increase its efficacy. One approach, called emotional awareness and expression therapy (EAET), combines techniques from several other psychologically-based therapies. That approach tries to reduce pain and other symptoms by framing FM as a central nervous system-based process that is strongly
influenced by emotions relating to trauma, adversity or conflict that are avoided or unexpressed. The model also encourages awareness and expression of those emotions. Compared to other non-pharmacological treatments, patients treated with EAET reported a reduction in pain, psychological symptoms and cognitive difficulties and improvements in functioning and life satisfaction. The results were comparable to those achieved through medication, but had the advantage of lasting for at least six months after treatment was stopped. As the model of EAET used in the trial did not include many CBT components, it is likely that combining these two therapies would produce even better results.
While the available evidence may not prove that trauma is linked to FM, it also does not prove that the condition cannot be caused by an injury or adverse event. However, it appears unlikely that trauma is the sole factor in the onset of FM. Instead, a combination of factors – including previous physical and psychological health and genetic susceptibility – are likely to work together to initiate and maintain FM, and it is difficult to determine the relative importance of any single factor in any one individual. By identifying risk factors that occur early in life, it may be possible to prevent chronic pain later in life and provide more effective treatments when it does occur. q
• Dr Ivan Ramos-Galvez is a consultant in pain medicine at the Royal Berkshire Hospital with a private practice at Spire Dunedin and Circle Hospitals in Reading. After extensive training in spinal surgery at the Oxford Deanery, he undertook further specialisation in pain medicine. His understanding of the interactions between those complex areas of medicine means he is often called upon to provide an opinion within his clinical practice, or as an expert witness where spinal surgery has led to complications.
Dr Ramos-Galvez has a special interest in neuropathic pain and CRPS and has developed a treatment portfolio ranging from simple oral anti-neuropathic agents to neuromodulation. Read his full biography and download his CV at www.medicolegal-partners.com/ramos-galvez.
