An abnormal lactulose breath test (LBT), indicative of small intestinal bacterial overgrowth, in fibromyalgia patients and in irritable bowel syndrome (IBS) patients may help to explain common features of the conditions, researchers report in the April issue of the Annals of the Rheumatic Diseases.
Dr. Mark Pimentel from Cedars-Sinai Medical Center, Los Angeles, California and colleagues note that nearly a third of fibromyalgia patients in some studies are also diagnosed with IBS, suggesting a causal link between the two disorders.
The researchers tested their hypothesis that the lactulose breath test would be abnormal in both IBS and fibromyalgia by performing the test in 42 fibromyalgia patients, 111 IBS patients, and 15 healthy controls.
All 42 patients with fibromyalgia had an abnormal LBT, compared with 93 (84%) of IBS patients and 3 (20%) of the controls.
Hydrogen production was significantly greater in fibromyalgia patients than in IBS patients or healthy controls. Moreover, the researchers note that in 41 fibromyalgia patients, there was a significant correlation between their visual analogue pain score and the peak hydrogen level and hydrogen area under the curve seen on the LBT.
“The additional finding in our study that the degree of pain in fibromyalgia seems to correlate with the degree of hydrogen suggests a possible link between the LBT findings and hyperalgesia,” the investigators write.
“This study suggests that an abnormal LBT may be a common link between subjects with fibromyalgia and IBS,” the authors conclude. “Further study is needed to determine if treatment and normalization of the breath test with antibiotic treatment can produce an improvement in fibromyalgia in addition to bowel complaints.”
Ann Rheum Dis 2004;63:450-452. (Reported on by Medscape – www.medscape.com)