Fibromyalgia pathophysiology

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

The cause of fibromyalgia is unknown. In fact it is not be due to a singular factor at all, but are due to a multiplicity of causes. Fibromyalgia does not, 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. Various hypothesis have been put through describing the pathogenesis of fibrommyalgia. Another study suggests that more than one clinical entity may be involved, ranging from a mild, idiopathic inflammatory process to clinical depression

Pathophysiology

The cause of fibromyalgia is unknown. In fact it is not be due to a singular factor at all, but are due to a multiplicity of causes. Fibromyalgia does not, 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. Various hypothesis have been put through describing the pathogenesis of fibrommyalgia. Another study suggests that more than one clinical entity may be involved, ranging from a mild, idiopathic inflammatory process to clinical depression

Stress

• Stress is a significant precipitating factor in the development of fibromyalgia.
• A non-mainstream hypothesis that fibromyalgia may be a psychosomatic illness has been described by John E. Sarno's "tension myositis syndrome".
• He believes many cases of chronic pain result from changes in the body caused by the mind's subconscious strategy of distracting painful or dangerous emotions.
• Education, attitude change, (and in some cases, psychotherapy) are treatments proposed to stop the brain from using that strategy.
• Robert G. Schwartz, MD has proposed an alternative view where in mind-body connections may play an important role in chronic disease (not just fibromyalgia). Through his program strategies to align incentives are offered.

Dopamine abnormality

• Dopamine is a catecholamine neurotransmitter known for its role in the pathology of schizophrenia, Parkinson's disease and addiction.
• Fibromyalgia has been commonly referred to as a "stress-related disorder" due to its frequent onset and worsening of symptoms in the context of stressful events.
• It was therefore proposed that fibromyalgia may represent a condition characterized by low levels of central dopamine that likely results from a combination of genetic factors and exposure to environmental stressors, including psychosocial distress, physical trauma, systemic viral infections or inflammatory disorders (e.g. rheumatoid arthritis, systemic lupus erythematosus).
• This conclusion was based on three key observations: (1) fibromyalgia is associated with stress; (2) chronic exposure to stress results in a disruption of dopamine-related neurotransmission and (3) dopamine plays a critical role in modulating pain perception and central analgesia in such areas as the basal ganglia;including the nucleus accumbens, insular cortex, anterior cingulate cortex thalamus, periaqueductal gray, and spinal cord
• As is the case with several of the neurotransmitters, there is evidence for a role of dopamine in restless leg syndrome, which is a common co-morbid condition in patients with fibromyalgia.
• Patients with restless legs syndrome have also been demonstrated to have hyperalgesia to static mechanical stimulation.

Serotonin

• 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.
• However, selective serotonin reuptake inhibitors (SSRIs) have met with limited success in alleviating the symptoms of the disorder.

Sleep disturbance

• The sleep disturbance hypothesis states that any event such as a trauma or illness causes sleep disturbance and also chronic pain that may initiate the disorder.
• According to the hypothesis stage 4 sleep is critical for normal functioning of the nervous system, as it is during that stage that certain neurochemical processes in the body 'reset'.
• It is during that stage 4 sleep, pain causes the release of the neuropeptide substance P in the spinal cord which has the effect of amplifying pain and causing nerves to become more sensitive to pain.
• If pain becomes chronic and body-wide this process can run out of control.
• The sleep disturbance hypothesis holds that deep sleep is critical to reset the substance P mechanism and prevent this out-of-control effect.
• The sleep disturbance/substance P hypothesis could explain "tender points" that are characteristic of fibromyalgia but which are otherwise enigmatic since their positions don't correspond to any particular set of nerve junctions or other obvious body structures.
• The hypothesis proposes that these locations are more sensitive because the sensory nerves that serve them are positioned in the spinal cord to be most strongly affected by substance P.
• This hypothesis could also explain some of more general neurological features of fibromyalgia, since substance P is active in many other areas of the nervous system.
• The sleep disturbance hypothesis could also provide a possible connection between fibromyalgia, chronic fatigue syndrome (CFS) and post-polio syndrome through damage to the ascending reticular activating system of the reticular formation.
• This area of the brain, in addition to apparently controlling the sensation of fatigue, is known to control sleep behaviors and is also believed to produce some neuropeptides, and thus injury or imbalance in this area could cause both CFS and sleep-related fibromyalgia.
• Electroencephalography 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.

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.
• Most patients with fibromyalgia with low IGF-I levels failed to secrete HGH after stimulation with clonidine and l-dopa.
• This view is supported by the fact that those hormones under the direct or indirect control of HGH, including IGF-1, cortisol, leptin and neuropeptide Y are abnormal in people with fibromyalgia.
• In addition, treatment with exogenous HGH or growth hormone secretagogue reduces fibromyalgia related pain and restores slow wave sleep though there is disagreement about the proposition.

Deposition disease

• The 'deposition hypothesis of fibromyaglia' poses that fibromyalgia is due to intracellular phosphate and calcium accumulations that eventually reaches levels sufficient to impede the ATP 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.
• Calcium is required for the excess phosphate to enter the cells. The additional phosphate slows down the ATP process; however the excess calcium prods the cell to continue producing ATP.
• The phosphate build-up hypothesis explains many of the symptoms present in fibromyalgia and proposes an underlying cause.

Other hypotheses

• 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.
• Another hypothesis on the cause of symptoms in fibromyalgia states that patients suffer from vasomotor dysregulation causing improper vascularflow and hypoperfusion (decreased blood flow to a given tissue or organ).

Associated Conditions

• Fibromyalgia is always a comorbid disorder, occurring in combination with some other disorder that likely served to trigger the fibromyalgia in the first place.
• Two possible triggers are gluten sensitivity and/or irritable bowel.
• Irritable bowel is found at high frequency in fibromyalgia and a large celiac support group survey of adult celiacs revealed that 7% had fibromyalgia and also has a co-occurrence with chronic fatique.
• In some cases, the original disorder abates on its own or is separately treated and cured, but the fibromyalgia remains. This is especially apparent when fibromyalgia seems triggered by major surgery.
• In other cases the two disorders coexist. Since it can be extremely complex to treat the source of fibromyalgia, and since it is most probably a multifactoral disorder that is different from one afflicted patient to the next, the concept of has been proposed.
• In this instance the total number of things that does not allow a patient to get well is treated, one at a time, taking into consideration the unique conditions of that individual patient.Reducing Total Load