Differences between CFS/ME and Fibromyalgia
Are Chronic Fatigue Syndrome and Fibromyalgia the Same Thing?
Nov 12, 2008
Fibromyalgia and CFS/ME have very similar symptoms. Some doctors think that they are the same illness, or two different sides of the same condition. Both can cause debilitating pain and fatigue as well as a myriad of other symptoms.
Similarities and Differences
There are several similarities between CFS/ME and fibromyalgia
- Similar symptoms, e.g. pain, fatigue, sleeping problems, cognitive impairment
- Commonly comorbid (occur together)
- Both are much more common in women (but so are most autoimmune diseases and some other illnesses)
- Some shared risk factors (e.g. joint hypermobility)
- Both are commonly comorbid with e.g. migraine, IBS, temporomandibular pain, multiple chemical sensitivity, sleep apnea, endometriosis and restless legs
But there are also differences
- Fibromyalgia has generally not been connected with viral and bacterial infections (with a few exceptions, such as mycoplasma and parvovirus B19)
- CFS/ME has occurred in epidemics, but none have been reported for fibromyalgia
- Fibromyalgia is not thought to ever be progressive or life-threatening (as CFS/ME can be in rare cases)
- Fibromyalgia does not usually cause severe immune dysfunction, neurological symptoms and exercise intolerance
- CFS/ME usually does not cause allodynia (exaggerated response to pain: non-painful stimuli experienced as painful)
- Diagnosis of fibromyalgia requires tender points (painful areas in the muscle that occur in certain places)
Causes
Another thing CFS/ME and fibromyalgia have in common is that the cause isn't known - but the same goes for many other conditions. Currently ICD-10 labels fibromyalgia as a functional disorder and CFS/ME as a neurological illness. But most doctors currently believe that fibromyalgia, too, has a neurological origin. Both illnesses can be seen as "misconfiguration" of the brain.
CFS/ME has been strongly connected with infectious agents, especially viruses. There is strong evidence that both enteroviruses and herpesviruses like HHV-6 can play a part. Fibromyalgia, on the other hand, is often triggered by a physical injury or trauma, but sometimes it is fully idiopathic (no cause or trigger is found).
Some doctors consider both CFS/ME and fibromyalgia to be autoimmune diseases. Both have been connected with some autoantibodies and fibromyalgia commonly occurs with some autoimmune illnesses (e.g. lupus and rheumatoid arthritis), but there is no convincing evidence of an autoimmune origin. Most medications used in autoimmune diseases are useless, except for low dose naltrexone.
The Bottom Line
How can you tell whether you have chronic fatigue syndrome/myalgic encephalomyelitis or fibromyalgia? Often people get one diagnosis but think they might have the other one - or both. If you don't have tender points, you don't have fibromyalgia. If you don't experience exercise intolerance or post-exertional malaise, you don't have CFS/ME. Usually it is not that simple, though.
Does it even matter which diagnosis you get? In most cases it doesn't. Both illnesses can be treated with many of the same drugs and supplements. In most countries it is equally difficult to get disability benefits with either diagnosis. But if you do have CFS/ME, it is much more important to avoid excessive overexertion, as recovery could take weeks, months or even years.
It is also important to avoid confusion with other illnesses. Hypothyroidism can be misdiagnosed as both fibromyalgia and CFS/ME, especially as most doctors do not realize that low normal thyroid hormone levels may not be adequate for everyone. There are many conditions that can cause pain and chronic fatigue, and some doctors may be too quick to make the diagnosis before overruling other possibilities.
