18% of patients with FM had been diagnosed with CFS, 80% of those with CFS had received a diagnosis of FM. Compared with control subjects, patients with CFS received diagnoses of CFS, FM, and IBS significantly more often. 80% of patients reported a history of clinician-diagnosed FM, the FM symptom score was high, yet on examination only 20% met American College of Rheumatology criteria for FM; only 18% of FM patients carried a diagnosis of CFS, although 64% actually met the Centers for Disease Control criteria. ~2000 Study
Unique features for CFS included fever or sore throat; for FM, a more frequent history of low back pain that was made better by heat or massage and was exacerbated with sitting or standing (above link). Fibromyalgia and CFS patients may exist on a continuum where patients first develop pain and then fatigue, however exercise improves fibromyalgia but can worsen me/cfs.
Some have suggested muscle dysfunction as a pathological mechanism behind CFS: ‘Bioenergetic muscle dysfunction is evident in CFS/ME, with a tendency towards an overutilisation of the lactate dehydrogenase pathway following low-level exercise, in addition to slowed acid clearance after exercise.’
Those who lump FM/CFS together and use mineral excretories such as guafenesin to address calcium accumulation in the muscles, support this view. Others maintain that true ‘fibromyalgia’ is where there are no observable muscle knots or pressure points causing pain, as the mechanism behind FM is the nervous system, as opposed to the muscles themselves.
Fibromyalgia patients have been shown to have more nerve endings in their hands, and also may experience central nervous system sensitisation (see blog post here for definition and management). This is interesting as some me/cfs studies suggest excessive sympathetic nervous system activation (at rest- and inadequate sympathetic activity during exercise). Fibromyalgia studies have suggested vagus nerve stimulation may be useful. Vagus nerve stimulation (VNS) is used in chronic pain and other illness and is hypothesised to reduce inflammation, oxidative stress, autonomic nervous system activity, the opioid response, central sensitization, and pain perception- and perhaps even reduce neuroinflammation and cytokines in the brain.
Reduced heart rate variability (HRV) findings suggest an underactive vagus nerve may not be keeping the sympathetic nervous system (fight/flight system) under control in chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM). Acute stressors can produce a SNS surge followed by an even more excessive parasympathetic rebound (with nauseous, sweating, lightheadedness, with diarrhea and fatigue). If you feel physically jacked up and bothered by small emotional or physical events and then depleted afterwards, this could be the reason. Pocinki also found that the inGUT microbiome, SIBO, dysbiosisitial PNS surge from taking a large breath caused a large SNS reaction followed by another PNS surge.Link
VNS has been used with depressed patients, as it elevates the activity of serotoninergic and noradrenergic neurons in the brain. Thus it may help with primary fibromyalgia patients- as seen in this small pilot study (though a significant portion of the sample had depression).
Interestingly, 42/42- 100% of fibromylagia patients were found to have Small Intestinal Bacterial Overgrowth (SIBO) through abnormal breath tests. This ties in with recent studies which suggest autoimmunity to bacteria, possibly through leaky gut syndrome- see GUT microbiome, SIBO, dysbiosis
Flattened diurnal cortisol is often found (adrenal fatigue) in fibromyalgia. See Cortisol
‘From fatigue to fantastic’ by Tietlebaum
‘What your doctor won’t tell you about fibromyalgia’
For an overview of fibromyalgia, see NY Times Article