Fibromyalgia is a common and potentially disabling condition predominantly affectinhg young to middle-aged women.1 Fibromyalgia has a varied and fluctuating clinical spectrum. The symptoms of Fibromyalgia are musculoskeletal pain and tenderness, sleep issues and significant levels of fatigue. The other key symptoms include cognitive disturbances, particularly problems with concentration, memory, and high distress levels.2 Fibromyalgia can be considered part of a group of clinical syndromes, including chronic fatigue syndrome, multiple chemical sensitivities and irritable bowel syndrome, whose clinical features reflect similar pathophysiological processes – termed by some as ‘central sensitivity syndromes’.3 These different diagnoses are used depending on the predominant clinical features. For example, patients with fatigue as their most severe symptom may receive a diagnosis of chronic fatigue syndrome.
Fibromyalgia has been thought to be caused by the development of changes in the central nervous system (CNS)4,5 that alter the processing of afferent sensory input, and can be grouped together under the term ‘central sensitisation’.6 Central sensitisation changes are often triggered by long-standing psychological or physical stress.7 These changes result in the intensity of usually non-painful stimuli being amplified and experienced as painful. Other effects include abnormality in the sleep cycle, where patients are unable to achieve deep, restorative, stage IV non-REM sleep, and disturbances in the hypothalamic-pituitary axis, with altered levels of serum cortisol, decreased 24-hour urinary free cortisol and blunted cortisol responses to dynamic testing.8
Genetic polymorphisms resulting in alteration in CNS serotonergic and catecholaminergic processes continue to be investigated, and appear to increase the risk of developing fibromyalgia.9
Aside from any genetic predisposition, clinical fibromyalgia is frequently triggered. In an internet survey of 2 596 fibromyalgia patients in North America, 79% described potential triggering events at the onset of the their fibromyalgia,10 while 88.7% of patients seen in an Australian public hospital fibromyalgia clinic reported recognisable triggers.11 A physical or psychological stressor in a susceptible individual can result in a chronic, maladaptive stress response, which, in turn, mediates the central changes.12
Fibromyalgia is diagnosed according to criteria published by the American College of Rheumatology (ACR). The initial classification criteria were published in 1990 and included widespread musculoskeletal pain and tenderness measured by the ‘tender point count’ on physical examination.13 These criteria was useful in defining a standard group for research purposes, however it did not and does not recognize the broader spectrum or fluctuating nature of fibromyalgia symptoms.
In 2010 the ACR published diagnostic criteria, taking these aspects into consideration.14 This criteria now accounts for chronic musculoskeletal pain, as well as fatigue, sleep problems, cognitive disturbance and other symptoms. In publishing this criteria, the authors recognised that fibromyalgia symptoms fluctuate significantly over time and they aimed to be able to recognise a spectrum of severity in patients with central sensitisation symptoms – rather than just those with the most severe illness who satisfied the traditional definition of fibromyalgia. The severity scale captured by the new criteria has been termed by some as a degree of ‘fibromyalgianess’ or a ‘polysymptomatic distress scale’.15,16 Recent research focus uses this gauge of central sensitisation symptom severity to investigate the extent of sensitisation syndrome features in patients with fibromyalgia, chronic pain and other associated conditions.16 It is clear, however, that many clinical features of central sensitisation are also found in a large number of other chronic illnesses.
The diagnosis of fibromyalgia is often not initially considered. In a large North American survey, 46% of fibromyalgia patients had consulted 3–6 health care providers regarding their symptoms, prior to their fibromyalgia diagnosis.10
When should fibromyalgia be considered?
Fibromyalgia has multiple, varied and fluctuating symptoms. It should be considered when a patient describes chronic musculoskeletal pain, fatigue and poor sleep. These symptoms are usually accompanied by a number of other problems such as depression or anxiety, sensitivity to chemicals, irritable bowel or restless legs. The symptoms often start or worsen during a period of severe psychosocial or physical stress.
The key symptoms of fibromyalgia are also commonly found in many other illnesses, and a thorough examination and investigation needs to be undertaken in order to ensure there is not another pathological cause for the symptoms – particularly if there are any ‘red flags’ in the patient’s history suggestive of another serious pathology (Table 1).
• Older age at new symptom onset
• Weight loss
• Night pain
• Focal pain
• Fever or sweats
• Neurological features
• History of malignancy