Fibromyalgia that is diagnosed and labelled by physicians in clinical practice and even research interchangeably with Chronic Fatigue Syndrome is still a controversy by some, while a clear diagnostic entity by others. As the label of fibromyalgia denotes, it is a condition of generalized body (musculoskeletal) and joint pains. The Chronic Fatigue Syndrome label indicates the patient suffering from a general body fatigue. These two labels if they are two conditions may overlap as some patients and present with both generalized symptom clusters. That is why the two conditions are considered by some as one and inter-related. While these conditions were misdiagnosed or under-diagnosed in the past, they may be over-diagnosed in the recent years. Either way the diagnosis of these conditions often is clinical and by history and physical examinations (only if muscle and joint tenderness present) as any lab or imaging tests are often non-conclusive. Therefore the pathophysiology of these conditions is still known by many as idiopathic, without any known aetiology or pathologic pathway(s).
More than a controversy, Fibromyalgia and Chronic Fatigue Syndrome (FCFS) are elusive and the diagnosis by many could be descriptive and clinical by symptoms counting like major depression. But there is at least one or more types of FCFS that are associated with many other medical conditions, e.g. IBS (Irritable Bowel Syndrome), non-ulcer dyspepsia, esophageal dysmotility, interstitial cystitis, chronic prostatitis, vulvodynia, vulvar vestibulitis, temporomandibular joint syndrome, sickle cell anaemia, osteoarthritis to name a few. The association with some of these comorbidities that are known as autoimmune disorders, could easily classify this type (s) of FCFS as an autoimmune condition(s) (1). The common conception behind the pathogenesis of FCFS is over-focussing on the pain symptoms that could be due to super-sensitivity or hyperalgesia of the nociceptive process in the central nervous system. But here the focus will be more on the type or types of FCFS that have some true underlying pathologies (1-2). This or these pathological condition (s) are inflammatory, systemic throughout the body and associated with one or more inflammatory or autoimmune disorders (e.g. 3-4).
In the Search of a True Pathologic Fibromyalgia & CFS:
A Chronic Pain Syndrome or A Systemic Musculoskeletal Inflammation?
The first thing to reach the truth of FCFS is to separate these two different conditions that currently are diagnosed under the generic umbrella of fibromyalgia and chronic fatigue syndrome. First of all since both a chronic pain syndrome due to hyperalgesia or super-sensitivity of the nociceptive receptors in the central nervous system, and a systemic musculoskeletal inflammation could cause chronic fatigue syndrome, this secondary or post-morbid condition in this article will be excluded and the literature on fibromyalgia is solely explored (5-8).
Although a systemic musculoskeletal inflammatory condition could cause chronic generalized body pain, but the reason for the pain is not hyperalgesia or hyper-sensitivity of the nociceptive receptors in the central nervous system, but peripheral inflammations. This inflammatory condition is separated and searched for its underpinning pathology as the true pathological fibromyalgia, as pain even a generalized type could be subjective and not a true objective and pathological condition. Even tenderness of the muscles and joints without any proof of underlying pathology such as inflammation could be all subjective. Therefore this subjective condition or “Chronic Pain Syndrome” that could be due to a hyperalgesia or hyper-sensitivity of the nociceptive receptors of the brain or in a simpler word due to hyper-perception of pain by an individual is separated from a true fibromyalgia in this paper. This sole pain condition that is simply subjective could be perhaps associated more with other subjective conditions such as depression or being influenced by psychosocial processes (9-12).
Fibromyalgia: A Systemic Musculoskeletal Inflammatory Condition
Unfortunately since most samples of fibromyalgia studies are mixed with chronic pain syndrome and other subjective conditions without any underlying physical pathology, the physical findings of any inflammatory biomarkers are below the real level of the pathological reality of the condition. But despite this limitation, there are studies that have been able to show the presence of an underlying inflammatory process in the true cases of fibromyalgia.
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