Common painful non-inflammatory disorder characterised by chronic generalised diffuse musculoskeletal pain/aching and fatigue with tenderness at specific points. Fibromyalgia is at the severe end of the spectrum of widespread pain. Affects up to 2-4% of population (however prevalence may depend on definition used in studies – could be up to 11%). F>M. Average age of onset is around 35-40yrs. As a diagnosis, it is being made with increasing frequency, buts its validity as a diagnostic entity has been somewhat controversial in the recent past – some consider it as a variant of an anxiety disorder or as a “garbage-bin” for many unexplained chronic pain problems.
Many theories – largely unknown. There seems to be a genetic predisposition (more common in females; first degree relatives have a higher incidence) with a trigger by stress, trauma, infection or inflammation. Also there appears to be an aberrant central pain control mechanism or central hyperexcitability. Suggestions also include it being a disorder of muscle energy metabolism, an immunopathologic disorder of muscle, due to non-restorative deep sleep, a neuroendocrine imbalance (especially involving the thyroid and/or hypophyseal hormones), a disorder of serotonin or somatomedin-C metabolism, a pain modulation disorder. No pattern of inheritance has been identified – but it may require a predisposing factor that is genetic and a triggering factor (eg trauma, sleep disturbance, infection, stress) for the syndrome to develop. Most commonly believed hypothesis is that it is due to an aberrant processing of sensory input in CNS. The tissue mediators of inflammation excite receptors changes in pain sensitivity.
Generally have chronic widespread ‘muscle’ pain – predominantly neck and back, fatigue, headaches, poor sleep, morning stiffness, Raynaud’s phenomenon and tender points.
Clues to diagnosis: “I hurt all over”; “tests show nothing” symptoms (fatigue, pain, headaches, sleep problems); “nothing works”; “doctors don’t know what I have”.
Pain is diffuse, persistent, deep, aching, throbbing – sometimes stabbing; usually bilateral;
Associated signs and symptoms :
Widespread pain (97.6%); tenderness in > 11/18 tender points (90.1%); fatigue (81.4%); morning stiffness (77%); sleep disturbance (74.6%); paraesthesias (62.8%); headache (52.8%); anxiety (47.8%); dysmenorrhoea (40.6%); sicca symptoms (35.8%); prior depression (31.5%); irritable bowel syndrome (29.6%); urinary urgency (26.3%); Raynauds phenomenon (16.7%)
Physical examination and investigations will show no evidence of joint, osseous or soft tissue pathology, but fibromyalgia may be associated with other conditions – irritable bowel syndrome, tension & migraine headaches, dysmenorrhoea, chronic fatigue syndrome, Lyme disease, hypothyroidism, exposure syndromes (eg Gulf war syndrome).
Criteria chronic diffuse aching with tenderness in at least 11/18 characteristic locations.
Characteristics locations bilaterally suboccipital muscle insertions at occiput; lower cervical paraspinals; trapezius at midpoint of the upper border; suspraspinatus at its origin above the medial sacpular spine; 2nd costochondral junction; 2cm distal to lateral epicondyle in forearm; upper outer quadrant of buttock; greater trochanter; knee just proximal to medial joint line.
Many autoimmune rheumatological conditions may initially present with features that are indicative of fibromyalgia. Main differential diagnoses are chronic fatigue syndrome and regional pain syndrome.
Other differential diagnosis – non-pathological fatigue; myofascial pain syndrome; SLE; rheumatoid arthritis; osteomalacia; polymyalgia rheumatica; systemic sclerosis; obstructive sleep apnoea; polymyositis/dermatomyositis; Lyme disease and post-Lyme syndrome; thyroid disease; parathyroid disease; postviral syndromes; chronic fatigue syndrome; psychogenic rheumatism; somatisation disorder; irritable bowel syndrome, exposure syndromes.
There is considerable overlap between fibromyalgia and myofascial pain syndrome (they may represent different parts of the same spectrum). Differential diagnosis between fibromyalgia and myofascial pain syndrome (both may coexist in the same person):
Myofascial pain syndrome: Fibromyalgia:
• localised point tenderness • generalised widespread tenderness in muscle and non-muscle
• palpable band of muscle or nodule • no nodule can be palpated
• muscles are easily fatigues patient experiences generalised fatigue, weakness, and sleep disturbance
• few tender points (<7) • diffuse tender points (>7)
• stimulation produces a specific referred pain pattern • stimulation produces diffuse pain complaints
• may have reactive hyperaemia or erythema • reactive hyperaemia or erythema are not present
• NSAID’s may be useful • NSAID’s not useful
• latent hypersensitivity but no zone of reference latent (generalised tenderness persists)
Schneider & Brady (2001) suggest a reconsideration of the diagnosis and classification of fibromyalgia as they consider the criteria for diagnosis to be too strict. They suggest that those who present with widespread tenderness and fatigue be divided into ‘classic fibromyalgia syndrome’ (sleep disorder, anxiety syndrome, depression, alteration of CNS chemistry) and ‘pseudo fibromyalgia’ (various disorders – organic diseases eg anaemia, hypothyroidism, multiple sclerosis; functional disorders eg improper diets; musculoskeletal disorders eg postural problems).
Quality of life is generally “miserable” need to listen to the patient’s “struggle” attempt to lesson the effects of the symptoms on the quality of life. No single treatment is effective need multiple modes of management.
Health professional and patient need to have an accepting attitude.
Patient education and reassurance (“it’s a real disease”) – patient support groups helpful
Percent of patients that respond to each intervention is generally small.
Thyroid hormone levels and regulation may need to be assessed.
NSAID’s (may help some local pain); amitriptyline, cyclobenzaprine, alprazolam help some; improved posture; local injection of tender points; aerobic exercise (has been shown to be beneficial for symptoms and general well being) ; adequate sleep/regular sleep schedule; EMG biofeedback; acupuncture; cognitive/behaviour therapy; TENS; chiropractic/osteopathy (some patients have benefited)
Prognosis often poor; 3% free of all pain at 3 year follow up . After 14 years, 67% felt better