Differential Diagnosis of CFS/CFIDS/ME and Fibromyalgia

Fibromyalgia (FM) means "soft tissue and muscle pain". The soft tissues are tendons and ligaments. It is a chronic pain syndrome often associated with the Chronic Fatigue Syndrome/Chronic Fatigue and Immune Dysfunction Syndrome/Myalgic Encephalopathy (CFS/CFIDS/ME) and sometimes confused with it. The pain can be severe enough to interfere with routine daily activities. It migrates, can be achy, throbbing, shooting, or stabbing, and is worse in areas used most, like the neck or back. FM is associated with "tender points" which are painful when pressure is applied to them. Individuals often say they awaken feeling as if they hadn't slept. A sudden onset of profound fatigue can occur during or following exertion. Many other symptoms are common to fibromyalgia, including stiffness on waking, memory and concentration problems, excessive sensitivity of the senses, headaches, Temporomandibular Joint Syndrome (TMJ), irritable bowel, and bladder and muscle spasm.

Fibrositis, an older name, is still used interchangeably with fibromyalgia.

Research authorities vary in viewpoint as to the relation of FM and CFS/CFIDS/ME, but the best research to date indicates that the two illnesses, while often associated, are different and separable—both in nature of causation and in their pathophysiologies (effects on processes in the body.) The fact that the two illnesses are the province of separate specialties can also lead to diagnostic problems. As a rheumatologist is trained in rheumatological illnesses, there are occurrences of CFS/CFIDS/ME being diagnosed as FM when the physician is not well versed in CFS/CFIDS/ME diagnosis. And an infectious disease specialist may be prone to misdiagnosing FM as CFS/CFIDS/ME. Therefore, when there is doubt about which illness a patient has, s/he should become familiar with the differences between the two illnesses and seek a physician who knows how to diagnose both illnesses.

Diagnosis of Fibromyalgia (FM)

The 1990 U.S. College of Rheumatology diagnostic criteria are straightforward:

1. Widespread pain for at least 3 months.
2. Pain in all four quadrants of the body: right side, left side, above and below the waist.
3. Pain in at least 11 of 18 specified tender points when they are pressed. These 18 sites cluster around the neck, shoulder, chest, hip, knee, and elbow regions.

No exclusions are made for the presence of concomitant radiographic or laboratory abnormalities.