Diagnosing Fibromyalgia

The diagnosis of fibromyalgia is currently based on the Classification Criteria developed by The American College of Rheumatology in 1990.  These diagnostic recommendations are based on 2 features:

1. A history of widespread pain of 3 months or more.  Widespread is defined as pain in an axial distribution plus pain of both left and right sides of the body, and pain above and below the waist. 
Thus, a patient with axial pain, plus pain in 3 body segments would qualify - as seen below.

2. The palpation of 18 specified locations of tenderness (so called “tender points”).  To make a diagnosis of fibromyalgia there needs to be pain on digital palpation of 11 or more out of the18 specified tender points.  The recommendations specify that the palpation be at a final force of 4 kg (the amount of pressure required to blanch a thumbnail) starting at 1 kg and incrementing by 1 kg at a rate of 1 kg per second.  The anatomical locations of the tender point locations are as follows

1. Occiput: Bilateral, at the suboccipital muscle insertions.
2. Low cervical: bilateral, at the anterior aspects of the  
    intertransverse spaces at C5-C7.
3. Trapezius: bilateral, at the midpoint of the upper border.
4. Supraspinatus: bilateral, at origins, above the scapula spine
    near the medial border.
5. Second rib: bilateral, at he second costochondral junctions,
    just lateral to the junctions on upper surfaces.
6. Lateral epicondyle: bilateral, 2 cm distal to the epicondyles.
7. Gluteal: bilateral, in upper outer quadrants of buttocks in
    anterior fold of muscle.
8. Greater trochanter: bilateral, posterior to the trochanteric
    prominence.
9. Knee: bilateral, at the medial fat pad proximal to the joint line. 

  Here are the approximate tender point locations on a mannequin:

 Other common symptoms

Symptoms such as sleep disturbance, fatigue, stiffness, skin fold tenderness, and cold intolerance, are common in fibromyalgia patients, but their inclusion did not improve diagnostic accuracy.  The recommended number of tender points -- i.e., 11 or greater -- was originally derived from a receiver operating curve and relates to the number giving the best sensitivity and specificity. 

Fibromyalgia pain typically waxes and wanes in intensity; flares are associated with unaccustomed exertion, soft tissue injuries, lack of sleep, cold exposure, and psychological stressors.  Although most patients have widespread body pain, there are typically one or two locations that are the major foci.   These pain foci often shift to other locations -- often in response to new biomechanical stresses or trauma.  Fibromyalgia is more than a muscle pain syndrome, as most patients have an array of other somatic complaints.  Nearly all fibromyalgia patients have severe fatigue, poor sleep, and post-exertional pain.  Other symptoms include: tension type headaches, cold intolerance, dry mouth, unexplained bruising, poor memory and concentration, fluid retention, chest pain, jaw pain, dyspnea, dizziness, abdominal pain, paresthesiae, and low grade depression and anxiety.  Some symptoms relate to specific syndromes whose prevalence appears to be increased; these include:  irritable bowel syndrome, irritable bladder syndrome migraine, premenstrual syndrome, Raynaud’s and restless leg syndrome.

Do you need blood tests and imaging tests to diagnose fibromyalgia?

The 1990 ACR recommendations state that "fibromyalgia is not a diagnosis of exclusion". This means that you do not need special tests to rule out other conditions. If a patient meets the historic and exam findings of tender points they can be diagnosed as having FM. This is an important concept, as some physicians only consider a diagnosis of FM after they have done exhaustive testing to rule out other conditions.
However, it is equally important to understand that FM often accompanies other conditions such as osteoarthritis, lupus (SLE), rheumatoid arthritits and multiple sclerosis. Thus, depending on the history and physical exam, further testing is often quite appropriate. In fact a careful evaluation for all other conditions that may be contributing to pain is an essential part of an informed treatment plan. However, I stress that the finding of another condition does not necessarily rule out a diagnosis of FM.

Acceptance of Fibromyalgia as a valid Diagnosis

The publication of the ACR criteria led to widespread interest and research into this disorder. For instance, the US Government provided research funding for fibromyalgia through the NIH, and both the Social Security Administration and the Veterans Administration recognize fibromyalgia as a potential cause for disability. More recently, the American Boards of Internal Medicine have included questions on fibromyalgia in their certifying examinations.  Interestingly many soldiers suffering from “Gulf-War Syndrome” have been found to have fibromyalgia. Here are some links to Government and other influential organizations that recognize fibromyalgia:

 http://www.ama-cmeonline.com/pain_mgmt/module08/06fibro/02_01.htm

The Social Security Administration recognizes fibromyalgia as a potential cause of disability - http://www.myalgia.com/SSA_FM

The American Boards of Internal Medicine requires that physicians taking their recertification examination be familiar with fibromyalgia - http://www.superscore.com/abim_recertification_exam_course.htm

The Veterans Administration recognizes fibromyalgia as a potential cause of disability - http://www.myalgia.com/vah disability.htm

The Mayo Clinic recognizes fibromyalgia as a common cause of pain - http://www.mayoclinic.com/invoke.cfm?id=DS00079

The Cleveland Clinic contributes to the WebMD website on fibromyalgia - http://www.clevelandclinic.org/arthritis/treat/facts/fibromyalgia.htm

The National Institutes of Health recognize fibromyalgia as a common problem - http://www.niams.nih.gov/hi/topics/fibromyalgia/fibrofs.htm

The National Institutes of Health supports research on fibromyalgia - http://www.niams.nih.gov/rtac/funding/grants/ep3.htm