Functional somatic syndrome: how it could be relevant to rheumatologists

Abstract

Functional somatic syndrome (FSS) is defined as a group of related syndromes characterized more by symptoms, suffering, and disability than by structural or functional abnormality. The diagnostic criteria and/or symptoms of FSS often overlap, and co-morbidity is commonly found among the diseases of FSS. For example, patients with irritable bowel syndrome often suffer from chronic pain, and a high percentage of co-morbidity can be found with fibromyalgia. Accumulating evidence indicates the presence of visceral and somatic hyperalgesia in FSS as a common feature, and the central sensitization mechanism has been suggested to play an important role in the pathophysiology of FSS. In the present article, the authors introduce the concept of FSS focusing on its possible relevance to rheumatology in terms of pain perception. A possible implication of mast cells and proteinase-activated receptor-2 (PAR-2) in FSS is also reviewed.

Developments in the scientific and clinical understanding of fibromyalgia

“…Functional somatic syndromes (FSS) are defined as a group of related syndromes characterized more by symptoms, suffering and disability than by structural or functional abnormality [17]. It is now known that FM overlaps and is associated with a variety of other FSS, including chronic fatigue syndrome, irritable bowel syndrome, post-traumatic stress disorder, and more.…”

A sudden onset of a pseudo-neurological syndrome after HPV-16/18 AS04-adjuvated vaccine: might it be an autoimmune/inflammatory syndrome induced by adjuvants (ASIA) presenting as a somatoform disorder?

“…In fact, patients fulfilling criteria for one syndrome often do it for others. At present, diagnostic criteria of FSS require a history of unexplained physical complaints, including several pain or pain-related symptoms (at least four), usually beginning before 30 years of age, persisting years (but, at least 6 months) and leading to significant impairment of individual global functioning, which usually carries to treatment seeking [33][34][35]. Therefore, the phenomenological denominations are being overcome, and it is supposed that all FSS might recognize similar pathological mechanisms.…”

“…Since then, the category of FSS has been applied to a growing number of syndromes, characterized by medically unexplained symptoms and by different denominations, depending on the type of symptoms and the main localization of pain (Fig. 1) [33]. That unification under the umbrella of FSS is supported also by the analysis of symptoms prevalence by syndrome, which revealed a considerable clinical overlap.…”

“…In this regard, also serotonergic and noradrenergic pathways have been suggested to play a role: indeed, they are involved in the transmission of emotional inputs, physical (autonomic) functions and pain regulation. Some reports raised a possible relationship between mast cells mediators and hyperalgesia [33,37]. Recently, Theoharides et al [38] reviewed a FSS subset as being neuroinflammatory syndromes, suggesting still elusive immunological mechanisms.…”

Sleep Disturbed by Chronic Pain in Fibromyalgia, Irritable Bowel, and Chronic Pelvic Pain Syndromes

“…Pain hypersensitivity/sensitization and stress-immune dysregulation are evident across these syndromes in the context of emotional arousal and physiologic activation. Because no clear pathological indicators are available, these conditions are sometimes referred to as functional somatic syndromes (FSSs) [2,3] or multisymptom illnesses [4]. Without the availability of definitive diagnostic tests, these conditions are mainly diagnosed through excluding other disease possibilities.…”