I have long suspected that subsets of fibromyalgia existed and should be studied. I think one of the roadblocks to finding successful treatment protocols in the past has been the tendency to lump all fibromyalgia patients together. In the end, it wouldn’t surprise me if scientists discover that several different problems or deficiencies result in what we know as fibromyalgia. Thankfully, some researchers are beginning to identify FM subsets and study how various treatments might help the FM patients who fall into those subsets.
Study 1: Growth hormone as concomitant treatment in severe fibromyalgia associated with low IGF-1 serum levels.
There is evidence of a deficiency of functional growth hormone in a subset of FM patients, identified by low serum levels of insulin-like growth factor (IGF-1). This study investigated the efficacy and safety of administering low doses of growth hormone in addition to the standard therapy patients were already receiving. Twenty-four patients with severe, prolonged fibromyalgia participated. Patients were randomly assigned to receive either a low dose of growth hormone in addition to standard therapy or standard therapy alone.
The results of the study were encouraging. The group receiving the growth hormone showed a 60 percent reduction in the mean number of tender points compared to the control group. Similar improvements were observed in the Fibromyalgia Impact Questionnaire scores and the Quality of Live visual analog scale. The administration of
growth hormone was well tolerated and most patients showed improvement within the first few months. No one discontinued the study due to adverse events.
The full report of this study can be downloaded here.
Study 2: A subset of fibromyalgia patients have findings suggestive of chronic inflammatory demyelinating polyneuropathy and appear to respond to IVIg.
Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated inflammatory disorder of the nervous system, caused by damage to the myelin sheath (the fatty covering that wraps around and protects nerve fibers) of the peripheral nerves. Since recent reports suggest that a subset of FM patients have an immune-mediated disease, the researchers set two objectives for their research: 1) To study FM patients for evidence of an immune-mediated demyelinating polyneuropathy; 2) To determine the effects of treating these FM patients with the immune modulator, intravenous immunoglobulin (IVIg).
Study participants included 58 FM patients, 26 rheumatic non-FM patients, and 52 non-rheumatic non-FM patients. Subjective measurements used were paraesthesias (skin sensations such as tingling, tickling, itching or burning), weakness, stocking hypaesthesia (tactile sensitivity), pain, fatigue and stiffness. Objective measures used were tenderness, proximal muscle strength and electrodiagnostic (EDX) evidence of polyneuropathy and demyelination.
Results showed that paraesthesias, subjective weakness and stocking hypaesthesia were more common in FM patients than in rheumatic non-FMS patients. And FM patients had less proximal muscle strength than rheumatic non-FMS patients. EDX demonstrated a distal demyelinating polyneuropathy, suggestive of chronic inflammatory demyelinating polyneuropathy (CIDP), in 33 percent of FM subjects. None of the rheumatic non-FM patients had polyneuropathy or demyelination. Subsequently, 15 FM/CIDP patients were subsequently treated with IVIg (400 mg/kg each day for five days). Their pain, tenderness and strength improved significantly and both fatigue and stiffness trended towards improvement.
This study was published in the February 2008 issue of the journal Rheumatology. The full text of the study can be purchased through the journal’s Web site.
Published On: January 27, 2008