Small bowel intestinal bacterial overgrowth linked to pain levels in fibromyalgia

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Rheumawire

Apr 5, 2004

Small bowel intestinal bacterial overgrowth linked to pain levels in

fibromyalgia

Los Angeles - Lactulose breath tests (LBT) suggest that patients with

fibromyalgia (FM) have bacterial overgrowth in the small intestine, and

the degree of breath test abnormality correlates with somatic pain

levels, Dr Mark Pimentel and colleagues report in the ls of the

Rheumatic Diseases[1].

" Our most important findings were that FM patients are more likely than

controls or inflammatory bowel syndrome (IBS) patients to have abnormal

LBT, that FM patients have higher hydrogen profiles, peak hydrogen, and

AUC than subjects with IBS, and that somatic pain levels in FM patients

correlate with the hydrogen level, " Pimentel tells rheumawire. " What we

hope this means is that the bacterial levels are higher in fibromyalgia

which could explain the hyperalgesia, since endotoxin is known to

produce hyperalgesia. "

The researchers had previously reported an association between IBS and

abnormal findings on the LBT [2]. They decided to examine LBT data in

fibromyalgia patients because bowel complaints are so common in that

disease, affecting up to 81% of FM patients [3]. There appears to be a

relationship between hydrogen levels on LBT and degree of bacterial

load.

The study included 42 subjects with FM,111 with IBS, and 15 normal

controls. After an overnight fast, baseline LBTs were performed and

subjects drank 10g of lactulose syrup. LBT was then repeated every 15

minutes for 3 hours and all test results were coded, randomized, and

interpreted by a blinded reader. The LBT was considered normal if there

was no rise in hydrogen or methane concentration before 90 minutes after

lactulose ingestion and no rise more of more than 20 ppm during 3 hours

of measurement.

All 42 of the FM subjects had abnormal LBT, versus 84% of the subjects

with IBS (p<0.05) and 20% of normal controls (p<0.0001). Hydrogen

production was significantly greater in the FM subjects than in the IBS

subjects (p<0.01), and peak hydrogen production was significantly higher

in the FM subjects than in the IBS group (p<0.00001).

" We were very surprised, " Pimentel says. " We had anticipated that there

might be a high prevalence of abnormal breath tests but were fortunate

to show the dramatically higher hydrogen production in the FM group. "

Forty-one of the 42 FM subjects completed visual analogue scores for

pain. In these patients, degree of pain correlated significantly with

peak hydrogen level (r-0.42, p<0.01), as did area under the curve and

pain score. This suggests that bacterial activity in the small bowel is

the reason for the correlation between FM pain and LBT findings.

" We have no proof in FM that there is an increased endotoxin level, but

this is a possible explanation for the findings, " Pimentel says.

The investigators write, " What remains to be determined is the

relationship between bacteria in the gut and hyperalgesia. " They note

that endotoxin produces global hyperalgesia and that translocation of

endotoxin-producing enteric organisms does occur in small intestinal

bacteria overgrowth. Such translocation has been linked to hepatic

inflammation due in part to a TNF-alpha response to endotoxin.

The obvious next question is whether using antibiotics to reduce the

small bowel bacterial environment and normalize the LBT might produce an

improvement in both FM pain and FM bowel complaints. Such an improvement

has already been documented for IBS patients treated with antibiotics

[2].

" We would like to conduct a double blind, randomized controlled trial

[of antibiotic treatment in FM] with endpoints being bowel symptoms,

somatic pain levels, and tender points, " Pimentel says.

Janis

Sources

1. Pimentel M, Wallace D, Hallegua D et al. A link between irritable

bowel syndrome and fibromyalgia may be related to findings on lactulose

breath testing. Ann Rheum Dis 2004; 63:450-452.

2. Pimentel M, Chow EJ, Lin HC. Normalization of lactulose breath

testing correlates with symptom improvement in irritable bowel syndrome:

a double-blind placebo-controlled study. Am J Gastroenterol 2003;

98:412-419.

3. Triadafilopoulos G, Simms RW, Goldenberg DI. Bowel dysfunction in

fibromyalgia syndrome. Dig Dis Sci 1991; 36:59-64.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org