Sunday, March 02, 2008

Fibromyalgia Is Not a Rheumatologic Disease Anymore

George T. Griffing, MD
Think of your last patient with difficult-to-treat fibromyalgia: Aren't they all? Did you refer that person to a rheumatologist?
Since the 1950s, when it was first described by Dr. Graham, "fibrositis" or fibromyalgia was thought to be a rheumatologic disorder because it was characterized by musculoskeletal pain similar to other rheumatologic diseases.[1]
In 1990, The American College of Rheumatology established diagnostic criteria based on the scoring of 18 potential tender points.[2] It turns out, however, that these tender points have nothing to do with fibromyalgia. Biopsy of the tender points shows no pathologic changes, and numerous studies have not shown any abnormalities in the musculoskeletal tissues that are painful.
Current evidence points to a neurologic disorder of central pain processing.[3] Fibromyalgia patients experience pain differently and have lower pain thresholds compared to normals. Research has demonstrated that various pain-related processes in the brain and spinal cord are abnormal in fibromyalgia.[4] But more work remains to be done.
Market surveys show the number one class of drugs used to treat fibromyalgia is nonsteroidal anti-inflammatory drugs.[5] Since fibromyalgia is not an inflammatory disease, it is not surprising we have a lot of treatment failures.
The pharmaceutical industry knows this, and they are viewing fibromyalgia as the prototypical central pain state. The 2 main drug classes of interest are the dual receptor reuptake inhibitors, like duloxetine or Cymbalta, and the antiepileptic drugs, like pregabalin or Lyrica. In fact, pregabalin has shown enough efficacy, that it is the first and only drug approved by the FDA for the treatment of fibromyalgia.[6]
Therefore, in the future, with new insights and therapies on the horizon, we will no longer need to refer our fibromyalgia patients to the rheumatologist.
That's my opinion. I'm Dr. George Griffing, Professor of Medicine at St. Louis University and Editor-in-Chief of Internal Medicine for eMedicine.

References
Graham W. The fibrositis syndrome. Bull Rheum Dis. 1953;3:33-34.
Wolfe F, Symthe 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.
Abeles AM, Pillinger MH, Solitar BM, Abeles M. Narrative review: the pathophysiology of fibromyalgia. Ann Intern Med. 2007;146:726-734.
Clauw DJ. Fibromyalgia: update on mechanisms and management. J Clin Rheumatol. 2007;13:102-109.
Rooks DS. Fibromyalgia treatment update. Curr Opin Rheumat. 2007;19:111-117.
Crofford LJ, Rowbotham MC, Mease PJ, et al. Pregabalin for the treatment of fibromyalgia syndrome: results of a randomized, double-blind, placebo-controlled trial. Arthritis Rheum. 2005;52:1264-1273.

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