New Diagnostic Criteria for Fibromyalgia
Twenty years after the American College of Rheumatology (ACR) published its first criteria for the diagnosis of Fibromyalgia, a new criteria has been proposed as an alternative method of diagnosis.
The 1990 Criteria 1
To be diagnosed with Fibromyalgia, patients need to have had pain in all four quadrants of the body (i.e. on both the left and right sides and above and below the waist) for at least 3 months.
Patients also need to have 11 out of 18 specifically chosen tender points. The tender points are spots on the body where everyone is more sensitive and so where it is easiest to test for the hypersensitivity to pain that characterises Fibro.
Issues with the 1990 Criteria
The following issues with the ACR 1990 classification definition have been identified 2:
The tender point count is rarely performed in primary care where most Fibromyalgia diagnoses occur, and when performed, is often performed incorrectly.
Many physicians do not know how to examine for tender points and some simply refuse to do so.
The importance of symptoms that had not been considered by the ACR Multicenter Criteria Committee (who published the 1990 Criteria) have become increasingly known and appreciated as key Fibromyalgia features: for example, fatigue, cognitive symptoms, and the extent of somatic symptoms.
A number of Fibromyalgia experts believe that tender points obscured important considerations and erroneously link the disorder to peripheral muscle abnormality.
Some physicians considered that Fibromyalgia is a spectrum disorder and is not well served by dichotomous criteria.
Patients who improve or whose symptoms and tender points decrease can fail to satisfy the ACR 1990 classification definition. It is not clear how to categorize or assess these patients.
The ACR 1990 classification criteria set such a high bar for diagnosis that there was little variation in symptoms among Fibromyalgia patients.
The 2010 Criteria 2
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This criteria set has been approved by the American College of Rheumatology (ACR) Board of Directors as Provisional. This signifies that the criteria set has been quantitatively validated using patient data, but it has not undergone validation based on an external data set. All ACR-approved criteria sets are expected to undergo intermittent updates.
A multicenter study of patients with a diagnosis of Fibromyalgia and a control group of rheumatic disease patients with noninflammatory disorders was carried out to address the issues of Fibromyalgia diagnosis and symptom severity. The objectives of this study were: 1) to identify non–tender point diagnostic criteria for Fibromyalgia; these criteria are not meant to replace the ACR classification criteria, but to represent an alternative method of diagnosis; 2) to integrate severity scale–based symptoms in these new clinical criteria, built on the characteristic features of Fibromyalgia; these criteria should be suitable for use in primary care and helpful in following patients longitudinally; and 3) to develop a Fibromyalgia symptom severity (SS) scale. 2
Criteria
A patient satisfies diagnostic criteria for fibromyalgia if the following 3 conditions are met:
- Widespread pain index (WPI) 7 and symptom severity (SS) scale score 5 or WPI 3–6 and SS scale score 9.
- Symptoms have been present at a similar level for at least 3 months.
- The patient does not have a disorder that would otherwise explain the pain.
Ascertainment
WPI: note the number of areas (below) in which the patient has had pain over the last week. In how many areas has the patient had pain? Score will be between 0 and 19.
Shoulder girdle, left; Hip (buttock, trochanter), left; Jaw, left; Upper back; Shoulder girdle, right; Hip (buttock, trochanter), right; Jaw, right; Lower back; Upper arm, left; Upper leg, left; Chest; Neck; Upper arm, right; Upper leg, right; Abdomen; Lower arm, left; Lower leg, left; Lower arm, right; Lower leg, right.
SS scale score:
Fatigue, Waking unrefreshed, Cognitive symptoms
For the each of the 3 symptoms above, indicate the level of severity over the past week using the following scale:
0 = no problem
1 =slight or mild problems, generally mild or intermittent
2 =moderate, considerable problems, often present and/or at a moderate level
3 = severe: pervasive, continuous, life-disturbing problems
Considering somatic symptoms in general, indicate whether the patient has:*
0 = no symptoms
1 = few symptoms
2 = a moderate number of symptoms
3 = a great deal of symptoms
The SS scale score is the sum of the severity of the 3 symptoms (fatigue, waking unrefreshed, cognitive symptoms) plus the extent (severity) of somatic symptoms in general. The final score is between 0 and 12.
*Somatic symptoms that might be considered: muscle pain, irritable bowel syndrome, fatigue/tiredness, thinking or remembering problem, muscle weakness, headache, pain/cramps in the abdomen, numbness/tingling, dizziness, insomnia, depression, constipation, pain in the upper abdomen, nausea, nervousness, chest pain, blurred vision, fever, diarrhea, dry mouth, itching, wheezing, Raynaud’s phenomenon, hives/welts, ringing in ears, vomiting, heartburn, oral ulcers, loss of/change in taste, seizures, dry eyes, shortness of breath, loss of appetite, rash, sun sensitivity, hearing difficulties, easy bruising, hair loss, frequent urination, painful urination, and bladder spasms.
Possible issues with the 2010 Diagnostic Criteria
The criteria removes hyperalgesia (sensitivity to pain) from the diagnostic criteria. This could be an issue because widespread hyperalgesia is one symptom that often differentiates Fibromyalgia from other conditions causing widespead pain.
Implicit in the 1990 ACR classification criteria was the requirement that clinical examination and clinical judgment had excluded other causes of chronic widespread pain, and such an exclusion is also implicit in the proposed diagnostic criteria. It is important for physicians to perform an appropriate clinical assessment to exclude other diagnoses, and/or to identify potential coexisting rheumatic diseases that may require treatment themselves. This is even more important with the 2010 Diagnostic Criteria as a measure of hyperalgesia has been removed.
In using the 2010 Diagnostic Criteria, it is crucial that not only have all comorbid conditions been identified, but that the patient can identify which symptoms are caused by their Fibromyalgia and which symptoms are caused by other conditions. Many patients would struggle with this, and it isn't uncommon for Fibromyalgia patients in the UK to have undiagnosed comorbidities when they are diagnosed with Fibromyalgia.
The 2010 Diagnostic Criteria, whilst being more user friendly to primary care physicians with little to training in performing the tender point examination, has the potential to lead to even more people being mis-diagnosed with Fibromyalgia.
References:
- Wolfe F, Smythe HA, Yunus MB, et al.: The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia. Report of the Multicenter Criteria Committee. Arthritis Rheum 1990, 33:160-172.
- Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB, Yunus MB. The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity. Arthritis Care Res (Hoboken). 2010 May;62(5):600-10.