Transparent Pain. But you don't Look Sick at All...

Manuela Di Franco, Cristina Iannuccelli
Reumatologia, Dipartimento di Medicina Interna e Specialità Mediche, Sapienza – University of Rome, Rome, Italy

The IASP (International Association for the Study of Pain) defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. 

Fibromyalgia (FM) is one of the most severe and disabling chronic pain syndromes characterized by the absence of structural pathology (so-called “organic cause”) and accompanied by fatigue, sleep, memory and mood issues. 

FM patients complain of strange and variable pain described from time to time  as burning, aching, sharping, stabbing, exhausting, cramping, gnawing, tingling, etc

This description of the pain changes during the hours, the days, the months, the years often with different and capricious characteristics. 
Because of that the patients are not taken into consideration by relatives and sometimes also by physicians. Their inexplicable pain is transparent and consequently the patients result “transparent”: they are not considered sick at all. 

The problem is that FM etiopathogenesis is still a matter of debate and consequently validated biological biomarkers have not yet been identified. Currently, according to 2016 ACR criteria, FM diagnosis is based exclusively on a comprehensive clinical assessment. 

A recent study showed as a patient-centered care and an empathetic behavior towards the patient are significantly higher for patients who have visible signs of pain (rheumatoid arthritis and complex regional pain syndrome) than for those who have no visible signs (Ehler–Danlos syndrome and fibromyalgia). 

How this disease can be made non-transparent? How those patients can be made “non-transparent”?

During the years there have been numerous attempts to find some markers for the disease but no one was conclusive. Recent attempts to make the pain objective included studies with functional magnetic resonance imaging that showed an abnormal resting state functional connectivity of the periaqueductal gray suggesting that patients with FM have an endogenous pain modulatory system dysfunction, possibly causing an impaired descending pain inhibition. Moreover some authors described a high prevalence of small fiber pathology in FM. 

Unfortunately those data are not so strong to be used in the clinical practice.
Likely it is necessary to look not only for biological or instrumental markers, but also for other possible markers such as psychological and anthropological findings. 

From a psychological point of view, various subgroups based on distinct characteristics have been identified (essential pain, concurrent distress, particularly depression and anxiety) suggesting the existence of heterogeneous and interacting etiopathogenetic processes. Clusters of patients have been also described using psychological measures but findings are not univocal. FM patients have been found to show a dysfunctional representation of their illness and to adopt coping strategies that are ineffective and focused on a catastrophic view. Conversely, one of the few protective factors that has been investigated in the context of chronic pain is pain acceptance, which seems to reduce negative emotions in response to pain and to favor effective pain coping strategies. 

From an anthropological point of view, chronic pain is a phenomenon determined by the interaction of several factors, which include cultural and social determinants. Specifically, experiences such as isolation and marginalization, sense of abandonment, lack of support, or complications in family, social, and work relationships can aggravate the level of psychological distress, which in turn adversely affects pain perception. At the same time, personal and social factors, such as lived trauma, subordination status, social suffering, or forced identity redefinition, can be considered as illness’ determinants in themselves.

The development of clinimetric assessment tools and/or patient-centered questionnaires tested on large population could be useful to evaluate FM pain and consequently to bring out the transparent pain.

To conclude pain invisibility can be a barrier to quality of care. It is necessary to educate caregivers to look to the transparent FM pain and to “transparent” FM patients in order not to underestimate this frequent condition.