Fibromyalgia Syndrome Diagnosis by Symptoms

Diagnosis of Fibromyalgia Syndrome (Fibro) is possible without the tender point test, or so suggests an article recently published in the German journal Zeitschrift für Rheumatologie.

A symptom-based diagnosis method for Fibro without needing the tender point examination would be helpful, especially as most examining physicians have had little to no training in how to best perform the tender point examination. The researchers aimed to test whether a symptom-based diagnosis of Fibro can be based on the symptoms of musculoskeletal pain and fatigue. [1]

The most frequent and severe symptoms in Fibro patients from four different settings were assessed using the Giessen Subjective Complaints List GBB 24. Of the respondents who filled in the list, 464 came from a self-help organisation, 162 from medical expertise, 33 from a private rheumatology practice and 36 from a tertiary-care pain department. The most frequent and severe symptoms were assessed and compared to those of a representative German population sample and a k-means cluster analysis was performed to identify sub-groups within the total sample of Fibro patients.[1]

The researchers found that the most frequent and severe symptoms in all four sub-samples were low back pain, limb pain and fatigue. The greatest difference between the Fibro patients and the healthy controls was with the symptoms "limb pain" and "fatigue". [1]

Cluster analysis identified three sub-groups of patients which were all characterized by severe limb pain and fatigue, as well as varying degrees of cognitive symptoms. [1]

The researchers concluded that:

"Following the exclusion of inflammatory rheumatoid, endocrinological and neurological diseases, a symptom-based clinical diagnosis of FMS can be based on of the key symptoms of chronic widespread musculoskeletal pain, as well as chronic fatigue." [1]

No mention is made however, of specific diagnoses that have been ruled out. Chronic myofascial pain for example is often confused with Fibro and one of the difficulties in accurately performing the tender point examination is the need for the examiner to be able to differentiate between myofascial trigger points and tender points. This suggested diagnosis by symptoms may not even try to exclude this condition. Multiple regional pain conditions, such as carpal tunnel and a back problem, could also be mis-diagnosed as Fibro with the suggested diagnosis here.

The tender point examination is far from ideal as a diagnostic tool: it biases diagnosis towards women; is often relied on despite being extremely badly performed; and needs an expert examiner in order to avoid false positive results. However, it is a relatively simple way of checking for the hyperalgesia (hypersensitivity to pain) that is a core symptom of Fibro.

If diagnosis of Fibro is to be made by symptoms alone, then exclusion of differential conditions needs to be far stricter than it currently is. Using a questionnaire looking for phrases such as "hypersensitive to pain", "even hugs hurt", "everything hurts, even my skin" and "pain that is unpredictable and moves around" would be far more accurate than simply looking for chronic widespread pain, which could be due to a number of causes that do not show up on regular test results.

References:

1. Häuser W, Akritidou I, Felde E, Klauenberg S, Maier C, Hoffmann A, Köllner V, Hinz A. [Steps towards a symptom-based diagnosis of fibromyalgia syndrome : Symptom profiles of patients from different clinical settings.] Z Rheumatol. 2008 Oct;67(6):511-5.