Diagnosis of IBS by the breath test is correct?


Office Uno Column; Yoshiharu Uno, M.d.,Ph.D.

 

 November 9, 2015, the prevalence of SIBO in functional gastrointestinal disorders (including IBS) was reported from Shimane Medical University. SIBO was diagnosed with glucose breath test (GHBT).

2015年11月9日、島根医大から、IBSを含む機能性胃腸障害でのSIBOの頻度が報告された。SIBOは、グルコース呼気テスト(GHBT)で診断された。

Small intestinal bacterial overgrowth in patients with refractory functional gastrointestinal disorders.

Shimura S, Ishimura N, Mikami H, Okimoto E, Uno G, Tamagawa Y, Aimi M, Oshima N, Sato S, Ishihara S, Kinoshita Y.

J Neurogastroenterol Motil. 2015 Nov 9. doi: 10.5056/jnm15116. [Epub ahead of print]

Abstract

BACKGROUND/AIMS:

Small intestinal bacterial overgrowth (SIBO) is considered to be involved in the pathogenesis of functional gastrointestinal disorders (FGID). However, the prevalence and clinical conditions of SIBO in patients with FGID remain to be fully elucidated. Here, we examined the frequency of SIBO in patients with refractory FGID.

METHODS:

We prospectively enrolled patients with refractory FGID based on Rome III criteria. A glucose hydrogen breath test (GHBT) was performed using a gas analyzer after an overnight fast, with breath hydrogen concentration measured at baseline and every 15 minutes after administration of glucose for a total of 3 hours. A peak hydrogen value ≥ 10 ppm above the basal value between 60 and 120 minutes after administration of glucose was diagnosed as SIBO.

RESULTS:

A total of 38 FGID patients, including 11 with functional dyspepsia (FD), 10 with irritable bowel syndrome (IBS), and 17 with overlapping with FD and IBS, were enrolled. Of those, 2 (5.3%) were diagnosed with SIBO, both of whom were initially diagnosed with FGID (1 with FD, 1 with overlapping FD and IBS). Their symptoms were clearly improved and breath hydrogen levels decreased to normal following levofloxacin administration for 7 days.

CONCLUSIONS:

Two patients initially diagnosed with FD and IBS were also diagnosed with SIBO as assessed by GHBT. Although the frequency of SIBO is low among patients with FGID, it may be important to be aware of SIBO as differential diagnosis when examining patients with refractory gastrointestinal symptoms, especially bloating, as a part of routine clinical care.

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 The morbidity of SIBO was only 5.3 percent.

SIBOはわずか5.3％だった。(SIBOはクラビットで除菌療法された。)

 
 Morbidity is low in Japan?

日本では、欧米よりSIBOは少ないのか？

 
しかし、 

その前に、そもそも、呼気テスト自体に問題がある。

出典：Ghoshal UC, Srivastava D. Irritable bowel syndrome and small intestinal bacterial overgrowth: Meaningful association or unnecessary hype. W J Gastroenterol 2014; 20: 2484-91.

 
 About positive rate of SIBO by the breath test, there is a difference between researchers.In different studies, frequency of SIBO among patients presenting with IBS varied from 4 to 78%.

Further, HBT and the HBT has a different positive rate.

Breath testing to diagnose SIBO is based on the principle that the gut bacteria readily ferment carbohydrates and produce gases.  These gases, once produced by the gut bacteria, readily diffuse into abdominal venous circulation and are transported to lung, where they are detected in exhaled breath.

Increasing bacteria always occurs gas symptoms?

Really will the gas is increasing?

This can be evaluated by plain abdominal X-ray.

空腸吸引液での陽性率は４％であるが、
グルコース呼気テスト(GHBT)では8.5～46％とあまりにその陽性率は異なっている。
そして、ラクツロース呼気テスト(LHBT)では34.5～78％と明らかに陽性率が高い。
 

このような状況においてこの診断法は正しいと言えるのであろうか？

再現性がない実験のレベルの試験ではないのか？

そもそも、SIBOを診断するための呼気テストは、小腸でガスが増えるために、それが血流に取り込まれて、肺からは排泄されることを原理としている。

であれば、
わざわざ呼気を調べるのではなく、グルコースやラクツロースを飲ませて、その前後のレントゲン写真を比較すればいいだけではないのか？

食後にお腹が張って痛くなるのであれば、
そして、それが食事による発酵が原因であるならば、
食前と食後（症状あり）のレントゲン写真を比較すればいいだけなのではないか？

 
 A 78-year-old female with a 2-year history of abdominal bloating was admitted to the hospital because of investigation of her symptom.

下のレントゲン写真は78歳の女性の食前の状況である。（2015年5月に経験した症例）
この患者は、食後2時間に嘔気、腹痛を毎日訴えていた。
この写真撮影時点では症状はなかった。

次の写真は、その直後にグルコースを100ｇ服用させ、
腹部症状を来した時点の写真である。

明らかに下腹部全体で小腸ガスが増加している。

After ingestion of 100 g glucose, the patient complained bloating and increased gas were demonstrated in the small intestine
 

Namely, simple and reasonable diagnosis of SIBO is possible by comparing the X-ray before and after ingestion of the glucose.
 

そのため、私はSIBOと診断し、除菌療法で軽快した。

このケースは、私に呼気テストは不要ではないか？
もっと確実に症状を反映する方法はないのか？
と考えさせるきっかけとなった。