~70% of me/cfs patients have *comorbid* fibromyalgia. Some have fibro initially but go on to develop ME/CFS later. They are not, however, the same condition. Fibromyalgia is dominantly pain, whereas people can have ME/CFS without pain being a dominant symptom. An infection usually triggers ME/CFS, whereas fibromyalgia is usually related to trauma.
– Brain: Fibro (and conditions like depression) show overactivity in certain areas of the brain whereas CFS doesn’t and is dominantly low blood flow. Reduced midbrain and cortical blood flow may be found in both [link].
– Immunity: They have different immune signatures. Flu-like Sore throats and swollen glands are a symptom of ME/CFS but not fibromyalgia.
– Nerves. Biopsy of small nerve fibres shows an increased density in fibromyalgia. (Equivalent studies have not been done for ME/CFS, this may in fact be a predisposing factor for later CFS). Small fibre peripheral neuropathy is being investigated in relation to both.
– Exercise: ME/CFS is worse from progressive exercise with PEM (brain fog, flu symptoms) with documented aerobic dysfunction which doesn’t improve as it should. Fibromyalgic well-being and endurance will usually improve with the same exercise regime.
– Antidepressants: Antidepressants help fibromyalgia. There is no proof of efficacy for ME/CFS.
– Depression is shown to worsen pain perception and coping, and catastrophising is an exacerbating factor in fibromyalgia. Depression is also common in ME/CFS but often follows the onset of PEM from pleasurable activities, rather than preceding it.
Diagnosis: Many fibromyalgia criteria are similar to ME/CFS with the exception of PEM. Earlier criteria omitted PEM and so may have resulted in some conflation.
– Treatment: There are some biomarkers tests and even a vaccine which may have efficacy for fibromyalgia. Diagnosis by cytokines and chemokines (Prohealth), (healthrising) (lab) or skin biopsy (research) is developing in place of pressure point diagnosis. The medical equivalent for ME/CFS is the CPET which shows aerobic impairment and dysfunction, immune activation from exercise and lack of recovery or improvement from exercise.
Cytokine pattern: Test results are based upon a 1–100 scoring system, with fibromyalgia patients having scores higher than 50. With sensitivity for FM/a® approaching 93%, patients can rely on a high degree of accuracy.
– Substance P, a neurotransmitter responsible for the transmission of pain is elevated in the spinal cord in FM but not CFS
– RNaseL, a cellular antiviral enzyme is elevated in CFS but not in FM. This may account for pain vs PEM differences.
– Sympathetic dominance is found in ME/CFS, whereas nervous system sensitisation is emphasised in fibromyalgia, though both show disturbed Stage 4 sleep.
– The similarities between ME/CFS and fibromyalgia are partially documented. Equivalent research is not always performed. Only recently a study was published showing orthostatic intolerance (POTS/NMH) is also common in fibromyalgia. SIBO was found in 100% of fibromyalgia patients but was not assessed in ME/CFS. Gut and metabolomic disturbances were found in ME/CFS but not assessed in fibromyalgia. Both disorders share similar comorbodities such as IBS and raynaud’s. Both show disturbances in cortisol suggesting suppression of the HPA.
[research] reduced serum or CSF serotonin levels; and suppression of growth hormone, somatomedin C, or IGF1
– authors such as [name] who promoted the ‘guafenesin protocol’ conflated CFS with fibro, and maintained that a cough medicine which affects the way calcium is managed within cells, causing it to be dumped, resulted in eventual clinical improvement after a period of exacerbation. This is consistent with Griffith universities recent research which relates SNP’s to calcium channel receptor issues throughout the body; they suggest magnesium may help. The clinical study on guafenesin, however, found no proof of efficacy and ME/CFS criteria were not considered.
– In the strictest sense of the term, fibromyalgia should be central nervous system dysfunction ONLY, in the absence of muscle knots and misalignments. This conflicts with ME/CFS or fibro patients who have muscle spasms as PEM crash symptom, misaligned hips and ribs, or muscle tightness (as suggested due to calcium overactivity). In this sense the diagnostic criteria is conflated and prevalence and research may not be accurate. Illness definition in ME/CFS is also conflated and research may not be accurate. Prevalence of ‘chronic fatigue’ (idiopathic) is 20%, prevalence of chronic fatigue syndrome is 2% and prevalence of ME/CFS is 0.2%. Prevalence of fibromyalgia is 6% according to labtest. Prevalence may also differ as ME/CFS requires exclusion of medical and psychiatric causes of fatigue.
– There is also a body of research focusing on ME/CFS & FM patients compared to pure CFS or pure FM (similarly to ME/CFS & IBS vs pure ME/CFS) with differences found between these groups also.
The most recent and comprehensive review ‘Evaluating the single syndrome hypothesis’ was published in 2013. ‘FM. By continuing to preserve the unique illness definitions of the two syndromes, clinicians will be able to better identify, understand and provide treatment for these individuals.’
Image: FM & CFS. Note the above differences for CFS by gender are likely not accurate.
See my other blogs on this topic:
– Brain scans in ME/CFS, fibromyalgia and mood disorders
– Differentiating ME/CFS from depression
– Fibromyalgia and CNSS