Fibromyalgia myths: The truth
Rheumatology (Oxford). 2008 Feb;47(2):208-11.
A subset of fibromyalgia patients have findings suggestive of
chronic inflammatory demyelinating polyneuropathy and appear to
respond to IVIg.
Dr Caro XJ, Winter EF, Dumas AJ.
Source
Division of Rheumatology, David Geffen School of Medicine at
UCLA, Los Angeles, CA, USA.
Abstract
OBJECTIVES:
The Cause of the fibromyalgia syndrome (FMS) remains unknown. Recent
reports, however, suggest that a subgroup of FMS subjects has an
immune-mediated disease. Therefore, our primary objective was to
study FMS subjects for evidence of an immune-mediated demyelinating
polyneuropathy. Our secondary objective was to determine the effects
of treating these FMS subjects with the immune modulator,
intravenous immunoglobulin (IVIg).
METHODS:
Fifty-eight FMS subjects, 26 rheumatic non-FMS subjects and 52
non-rheumatic non-FMS subjects were studied. Subjective measures of
paraesthesias, weakness, stocking hypaesthesia, pain, fatigue and
stiffness were made. Objective measures of tenderness, proximal
muscle strength and electrodiagnostic (EDX) evidence of
polyneuropathy and demyelination were also made. Eleven other FMS
subjects underwent sural nerve biopsy.
RESULTS:
Paraesthesias, subjective weakness and stocking hypaesthesia were
more common in FMS than in rheumatic non-FMS (P < or = 0.0001).
Proximal muscle strength was less in FMS than in rheumatic non-FMS
(P < or = 0.0001). EDX demonstrated a distal demyelinating
polyneuropathy, suggestive of chronic inflammatory demyelinating
polyneuropathy (CIDP), in 33% of FMS subjects. No rheumatic non-FMS
subject had polyneuropathy (P = 0.005), or demyelination (P = 0.05).
Fifteen FMS/CIDP subjects were subsequently treated with IVIg (400
mg/kg each day for 5 days). Pain (P = 0.01), tenderness (P = 0.001)
and strength (P = 0.04) improved significantly. Fatigue and
stiffness trended towards improvement.
CONCLUSIONS:
A significant subset of FMS subjects have clinical and EDX findings
suggestive of CIDP. IVIg treatment shows promise in treating this
subset. These observations have implications for better
understanding and treating some FMS patients.