Fibromyalgia is a disorder classified by the presence of chronic widespread pain and tactile allodynia (allodynia=is a painful response to a usually non-painful stimulus and can be either static or mechanical. It differs from reffered pain but can occur in areas other than the one stimulated. It is also differs from hyperalgesia, an extreme reaction to a stimulus which is normally painful.) While the criteria for such an entity have not yet been thoroughly developed, the recognition that fibromyalgia involves more than just pain has led to the frequent use of the term “fibromyalgia syndrome”. It is not contagious, and recent studies suggest that people with fibromyalgia may be genetically predisposed. The disorder is not directly life-threatening. The degree of symptoms may vary greatly from day to day with periods of flares (severe worsening of symptoms) or remission; however, the disorder is generally perceived as non-progressive.
The cause of fibromyalgia is unknown. Fibromyalgia can, but does not always, start as a result of some trauma such as a traffic accident, major surgery, or disease. Some evidence shows that Lyme Disease may be a trigger of fibromyalgia symptoms. Another study suggests that more than one clinical entity may be involved, ranging from a mild, idiopathic inflammatory process to clinical depression.
Fibromyalgia may exhibit a modest genetic component; if one pair of an identical twin has chronic widespread pain, there is a a 15% chance their twin will as well; the risk is only 7% for fraternal twins.
- StressStress is a significant precipitating factor in the development of fibromyalgia, and that PTSD (Posttraumatic Stress Disorder) is linked with fibromyalgia.
- Sleep disturbanceElectroencephalography studies have shown that people with fibromyalgia lack slow-wave sleep and circumstances that interfere with stage four sleep (pain, depression, serotonin deficiency, certain medications or anxiety) may cause or worsen the condition. According to the sleep disturbance hypothesis, an event such as a trauma or illness causes sleep disturbance and possibly initial chronic pain that may initiate the disorder.
Other hypotheses have been proposed related to various toxins from the patient’s environment, viral causes such as the Epstein-Barr Virus, growth hormone deficiencies possibly related to an underlying (maybe autoimmune) disease affecting the hypothalamus gland, an aberrant immune response to intestinal bacteria, neurotransmitter disruptions in the central nervous system, and erosion of the protective chemical coating around sensory nerves. A 2001 study suggested an increase in fibromyalgia among women with extracapsular silicone gel leakage, compared to women whose implants were not broken or leaking outside the capsule.
Cutting across several of the above hypotheses is the proposition that fibromyalgia is almost always a comorbid disorder, occurring in combination with some other disorder (or trauma) that likely served to “trigger” the fibromyalgia in the first place.
Dopamine is a catecholamine neurotransmitter perhaps best known for its role in the pathology of schizophrenia, Parkinson’s disease and addiction. There is also strong evidence for a role of dopamine in restless leg syndrome, which is a common co-morbid condition in patients with fibromyalgia. In support of the dopamine hypothesis of fibromyalgia, a reduction in dopamine synthesis has been reported by a study that used positron emission tomography (PET) and demonstrated a reduction in dopamine synthesis among fibromyalgia patients in several brain regions in which dopamine plays a role in inhibiting pain perception, including the mesencephalon, thalamus, insular cortex and anterior cingulate cortex.
Serotonin is a neurotransmitter that is known to play a role in regulating sleep patterns, mood, feelings of well-being, concentration and descending inhibition of pain. Accordingly, it has been hypothesized that the pathophysiology underlying the symptoms of fibromyalgia may be a dysregulation of serotonin metabolism, which may explain (in part) many of the symptoms associated with the disorder.
Human growth hormone
An alternate hypothesis suggests that stress-induced problems in the hypothalamus may lead to reduced sleep and reduced production of human growth hormone (HGH) during slow-wave sleep. People with fibromyalgia tend to produce inadequate levels of HGH.
The ‘deposition hypothesis of fibromyaglia’ posits fibromyalgia is due to intracellular phosphate and calcium accumulations that eventually reaches levels sufficient to impede the ATP (Adenosine Triphosphate) process, possibly caused by a kidney defect or missing enzyme that prevents the removal of excess phosphates from the blood stream. Accordingly, proponents of this hypothesis suggest that fibromyalgia may be an inherited disorder, and that phosphate build-up in cells is gradual but can be accelerated by trauma or illness.