Methods of Diagnosis of Fibromyalgia: Diagnosis Using the ACR 1990 Criteria
- 1 Source
- 2 Author’s opinion on the advantages this method has over current purely subjective tests
- 3 Summary of the two main aspects
- 4 Diagnostic classification
- 5 The issue of borderline fibromyalgia
- 6 Method of palpation of tender points in testing for the ACR 1990
- 7 Author’s criticism of digital palpation, and the opportunity to improve on it
These are the criteria based on a document called the “The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: Report of the Multicenter Criteria Committee. Wolfe, F., Smythe HA, Yunus MB, Bennett RM, Bombardier C, et al., Arth. Rheum., 33, 160,1990 available in full online at: https://www.rheumatology.org/Portals/0/Files/1990_Criteria_for_Classification_Fibro.pdf”.
They were written by leading experts. They rely on the presence of widespread pains and the presence of at least 11 out of 18 tender points.
Author’s opinion on the advantages this method has over current purely subjective tests
In the opinion of the author, mechanical allodynia (painful over-reaction to mechanical pressure) is a critical central feature of fibromyalgia. The new criteria, since 2000, do not require testing for tender points, which is in effect saying that mechanical allodynia is not critical. Everyone can agree that a patient with widespread pain who does not have mechanical allodynia is different than one who does have it, so all should agree that tender point examination adds more information.
Any diagnosis that is based only on questions is by definition purely subjective.
The tender point exam is semi-objective in that they be accompanied by not only the subjective experience of pain but also the observable changes of facial expressions vocalization and withdrawal reflexes. This is an advantage over a purely subjective test. The tender point exam has great educational value to the patient because if they observe their reactions they quickly learn that they have a disorder of the pain system. Typically the observe that they had pain reactions in parts of their body where they have little or no pain. This sometimes comes a surprise to them.
They may not know that they are more tender and at lower forces than the general public, and it is helpful to notify them of this.
Summary of the two main aspects
These criteria can be summarized as follows:
History of widespread pain
Pain is considered widespread when all of the following are present: pain in the left side of the body, pain in the right side of the body, pain above the waist, and pain below the waist. In addition, axial skeletal pain (cervical spine or anterior chest or thoracic spine or low back) must be present. In this definition, shoulder and buttock pain is considered as pain for each involved side. "Low back” pain is considered lower segment pain.
Pain in 11 of 18 tender point sites on digital palpation
Pain, on digital palpation, must be present in at least 11 of the following 18 tender point sites:
Occiput: bilateral, at the suboccipital muscle insertions.
Low cervical: bilateral, at the anterior aspects of the intertransverse spaces at C5-C7.
Trapezius: bilateral, at the midpoint of the upper border.
Supraspinatus: bilateral, at origins, above the scapula spine near the medial border.
Second rib: bilateral, at the second costochondral junctions, just lateral to the junctions on upper surfaces
Lateral epicondyle: bilateral, 2cm distal to the epicondyles.
Gluteal: bilateral, in upper outer quadrants of buttocks in anterior fold of muscle.
Greater trochanter: bilateral, posterior to the trochanteric prominence.
Knee: bilateral, at the medial fat pad proximal to the joint line.
The authors state: “For classification purposes, patients will be said to have fibromyalgia if both criteria are satisfied. Widespread pain must have been present for at least 3 months. The presence of a second clinical disorder does not exclude the diagnosis of fibromyalgia.” (Comment on copyright: This short quotation is used under fair use provisions for educational reasons. It was clearly intended to be a guideline by the authors to physicians to e u se d clinically. It is not practical to paraphrase it and still preserve the exact meanings.)
The issue of borderline fibromyalgia
What if a patient has only had the pains for 11 weeks? What if they tell the doctor they were much worse two months ago, but they are getting more sleep now? What if their case was always minor, but they are feeling better now because of medication? If any of these people failed to meet all the criteria, they may have “borderline fibromyalgia” or “fibromyalgia in recovery”.
Method of palpation of tender points in testing for the ACR 1990
Digital palpation should be performed with an approximate force of 4 kg.
Tender points are only to be considered ‘positive’ if the subject states that palpation was painful.
Author’s criticism of digital palpation, and the opportunity to improve on it
Digital palpation is no adequately standardized because of differences between how any two clinicians apply it. These differences involve varying thumb tip sizes, approach speeds, precise duration of application of force and angle of thumb approach. Ideally, as many of them as possible should be standardized using a hand held mechanical algometer with a standardbred size disk shaped tip. This should be fixed such as at 1-squared-cm wide disc, or a disc with one-squared-cm of surface area.
The old criteria did not measure indicators of central sensitization such as facial grimaces or withdrawal reactions. This can be added. Now with YouTube, mass training is much easier, but doctor need to be convinced that it is worth their time. Fee codes are needed so they can do the extra work, possibly with video to capture the facial expressions and moans, etc.