Fibromyalgia vs. CFS, differences in symptoms, causes, and treatment

fibromyalgia vs chronic fatigue syndromeFibromyalgia and chronic fatigue syndrome (CFS) are two conditions that are often mistaken for each other because of their numerous similarities. At the same time, there are some key differences that distinguish one from another, and these differences help doctors properly diagnose one or the other.

Some experts suggest that fibromyalgia and CFS are related conditions and are quite similar, even interchangeable. Others believe they are two completely separate conditions, and there is still a very small group that contests that either condition exists at all.


It’s easy to say that there are definitely similarities between fibromyalgia and chronic fatigue syndrome, and some patients may even have both conditions together. But to avoid any confusion we will outline those key differences in symptoms, causes, and treatment in order to provide you with a better understanding of both.

Connection between fibromyalgia fatigue and chronic fatigue syndrome

Fatigue is seen as a primary symptom of both fibromyalgia and CFS. Because the presence of fatigue is so strong in both fibromyalgia and CFS, many doctors believe that one condition is actually an expression of the other.

Fibromyalgia affects a greater amount of people than CFS, with five million Americans living with fibromyalgia compared to only one million living with CFS. But the line between fibromyalgia and CFS is so thin that studies have shown many fibromyalgia patients – up to 50 percent – also meet the criteria for CFS.

Fibromyalgia researchers are often rheumatologists and arthritis experts, whereas those who study CFS are often immunologists and virus experts. Due to research differences, fibromyalgia is often believed to be a muscle disorder whereas CFS is believed to stem from an infection.

Another strong commonality is the age of occurrence. Both conditions typically occur in mid-life and affect women more than men.

There is still much research required in order to have a better understanding of both conditions.

CFS and fibromyalgia rating scale

Both CFS and fibromyalgia can vary greatly in severity, with some patients living fairly normal lives unfazed by their condition and others who can barely perform daily tasks. A rating system can help you compare your day-to-day symptoms and determine whether you are improving or worsening. Below is the rating system you can use to gauge either condition.

 CFS & Fibromyalgia Rating Scale
100Fully recovered. Normal activity level with no symptoms.
90Normal activity level with mild symptoms at times.
80Near normal activity level with some symptoms.
70Able to work full time but with difficulty. Mostly mild symptoms.
60Able to complete about 6-7 hours of work a day. Mostly mild to moderate symptoms.
50Able to complete about 4-5 hours of work (or similar activity at home) a day. Daily rests required. Symptoms mostly moderate.
40Able to leave house every day. Moderate symptoms on average. Able to complete about 3-4 hours of work (or activity like housework, shopping, computer use) a day.
30Able to leave house several times a week. Moderate to severe symptoms most of the time. Able to do about 2 hours a day of work at home or activity like housework, shopping, computer use.
20Able to leave house once or twice a week. Moderate to severe symptoms. Able to concentrate for one hour or less per day.
10Mostly bedridden. Severe symptoms.
0Bedridden constantly. Unable to care for oneself.

Fibromyalgia vs. CFS: U.S. prevalence and economic impact

Roughly two to four percent of the U.S. population are affected by fibromyalgia. Estimates of U.S. prevalence were done based on the 1990 American College of Rheumatology (ACR) guidelines for the fibromyalgia diagnosis, which accounted for roughly 10 million cases of fibromyalgia. But it has since been argued that these estimates are too low and the guideline fails to capture many patients who could be living with fibromyalgia unknowingly.

Some estimates of the economic impact of fibromyalgia amount to over $10,000 per patient annually. On average, a fibromyalgia patient will miss up to 17 days of work.

CFS, on the other hand, affects 0.2 to 0.7 percent of the population. The estimated costs of CFS are $9 to $14 billion annually, and nearly one-quarter of these costs are paid out of pocket. Lost productivity costs are estimated between $9 and $37 billion, and CFS patients are less likely to get employed due to disability.

Distinguishing between fibromyalgia and CFS signs and symptoms

Migraine headaches with auras may double the risk of strokeSigns and symptoms similar to both fibromyalgia and CFS include anxiety and depression, fatigue, unrefreshing sleep, irritable bowel syndrome symptoms – such as bloating, diarrhea, and constipation – chronic headaches, association with temporomandibular joint syndrome (TMJ), thinking and memory difficulties, dizziness, and impaired coordination.

Even though there are so many similarities between the signs and symptoms of both fibromyalgia and CFS, there are distinguishing differences, too. For starters, pain is the primary symptoms in fibromyalgia and fatigue is the primary symptom in CFS. Fibromyalgia pain is widespread and chronic, and can be accompanied by fatigue. Fatigue in CFS is worse than just normal fatigue and can be so severe that is prevents a person from doing anything.

Also, in CFS flu-like symptoms may appear, and CFS patients show chronic immune system activation as if their bodies are fighting off an infection. Fibromyalgia diagnosis does not include checking for a low-grade fever and sore throat – unlike CFS, which does. Fibromyalgia can often be treated by targeting emotional or physical trauma. The pain can be improved through massage techniques, which is not the case in the CFS pain.

These key differences can help not only diagnose either condition quicker but can help better choose a more effective treatment method.

Difference between CFS and fibromyalgia causes

The exact cause of chronic fatigue syndrome is unknown, but it has been speculated that viruses, low blood pressure, a weakened immune system, and hormonal imbalances could contribute to CFS. Other theories suggest that some individuals may have a genetic disposition for the condition.

Although it has been suggested that a viral infection could result in CFS, no known infection has been highlighted as a possible cause. So far, Epstein-Barr virus (EBV), human herpes virus 6, Ross River virus (RRV), rubella, Coxiella burnetti, and mycoplasma have been studied as possible causes for CFS.

The CDC suggests that CFS may be the end stage of other diseases rather than being a separate disease on its own. For example, 10 to 12 percent of people with Epstein-Barr virus, Ross River virus, and Coxiella burnetti develop a condition that meets the criteria for a CFS diagnosis.

Also, patients with CFS often have weakened immune system, but whether this is a cause or part of CFS is unclear.

The cause of fibromyalgia is largely theorized, as it is not well understood. Researchers and doctors believe that a fibromyalgia patient experiences amplified pain as a result of abnormal sensory processing in the central nervous system. Much research has detected physiological abnormalities in fibromyalgia, including increased levels of substance P in the spinal cord, low levels of blood flow to the thalamus region of the brain, HPA axis hypofunction, low levels of serotonin and tryptophan, and abnormalities in cytokine function. Other fibromyalgia triggers include genetic factors and traumatic events or injuries.

CFS and fibromyalgia differences in risk factors

Being a female, having a family history of fibromyalgia or having a close relative with fibromyalgia, and having another rheumatic disease increase your risk of fibromyalgia.

Risk factors for CFS include being a female, being 40 to 50 years of age, and having difficulty managing stress.

CFS vs. fibromyalgia diagnosis and treatment

doctor signs of chronic inflammatThere isn’t a specific test for chronic fatigue syndrome, so at first your doctor will try to rule out other conditions that may have similar symptoms. These conditions may include ruling out a sleep problem by undergoing a sleep test, conducting lab tests to look at your blood, and possibly having your mental health evaluated by speaking with a counselor.

Diagnostic criteria for CFS includes memory and thinking issues, sore throat, enlarged lymph nodes, unexplained muscle pain, pain that moves without redness or swelling, headache, unrefreshing sleep, and extreme exhaustion lasting for over 24 hours.

There isn’t a specific test for fibromyalgia either, but doctors may use a form of testing that checks 18 specific trigger points, which have been found to be in majority of fibromyalgia patients. Not all doctors use trigger point exams anymore, but rather they narrow in on a fibromyalgia diagnosis if a person has experienced widespread pain for at least three months. Your doctor may also refer you for some blood work to rule out other conditions.

Treating fibromyalgia can be difficult as its exact cause is unknown. Therefore, the goal of fibromyalgia treatment is symptom management. A doctor may prescribe analgesics, or painkillers, to address fibromyalgia. However, there is a risk of developing an addiction to these drugs, so doctors may recommend this option with caution. Nonsteroidal anti-inflammatory drugs (NSAIDs) can also be taken for pain management, but once again long-term use of these drugs can yield unwanted side effects. In some cases, antidepressants may be prescribed as well.


Some alternative and complementary therapies and treatments for fibromyalgia include massages, acupuncture, cognitive behavioral therapy, movement therapies, and chiropractic.

Treatments for CFS can include medications such as antidepressants and sleeping pills, and therapy like graded exercise where the therapist works with the patient, and psychological counseling to discuss your feelings and limitations living with CFS as the syndrome may trigger anxiety or depression.

Neither fibromyalgia nor CFS have a cure.


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