Application of the Glucose Hydrogen Breath Test for the Detection of Bacterial Overgrowth in Patients with Cystic Fibrosis––A Reliable Method?

Abstract

Patients with cystic fibrosis (CF) have recently been deemed highly susceptible for bacterial intestinal overgrowth (BIO). We aimed to define the prevalence of BIO in children with CF by applying the H(2)-glucose breath test. Forty children with CF and ten healthy children received 1 g/kg D-glucose orally. Breath samples for H(2) content (ppm) were collected for 3 h. BIO was suspected if the breath hydrogen content increased by more than 20 ppm or if baseline concentrations topped 20 ppm. In 27 of 40 CF children (68%), breath hydrogen content exceeded 20 ppm. Whereas the breath hydrogen exhalation persisted above 20 ppm in almost all these children throughout the sampling period, none of the remaining children increased above this threshold. The high rate of CF children with elevated fasting hydrogen breath concentrations indicates that this phenomenon is less a sign of BIO rather than a consequence of global malabsorption and intestinal dysmotility.

Gastrointestinal transit times and motility in patients with cystic fibrosis

“…We do not find that the patients have a generalized motility disorder as have previously been suggested [9,11]. Frequency patterns of contractions in the small intestine found with MTS-1 in this study are in agreement with studies using manometry [27].…”

“…This was indeed one of the aims of the present study, why MTS-1 was found to be a suitable choice of method. Other major methodological restrictions are present when performing breath tests in patient groups where bacterial overgrowth is common, including CF patients [9], where passing of the ileal-cecal junction is masked. Scintigraphy, recognized as the gold standard for assessment of gastric emptying time and small intestinal transit time, also has the disadvantage that most protocols determine orocecal transit time.…”

“…Breath test is easy to perform and widely used but associated with substantial sources of error [8]. Performing breath test in subjects with small intestinal bacterial overgrowth, as often seen in CF patients, will lead to inaccurate results [9]. Equally important, the method does not differentiate between transit time of the stomach and small intestine.…”

Hydrogen Breath Test – Diet and Basal H₂ Excretion: A Technical Note

“…Moreover, 1–4% of potentially absorbable starch escapes absorption in the small bowel in normal subjects and is fermented by the large bowel flora. Indeed, high basal H 2 excretion has been reported in patients with carbohydrate malabsorption [13,14] and some authors hypothesized that high fasting H 2 excretion may suggest intestinal malabsorption [15,16,17]. …”

Abdominal pain in adults with cystic fibrosis

“…Using the hydrogen glucose breath test as the diagnostic test, between 32 and 68% of CF patients were tested positive [19,21,22]. The hydrogen glucose breath test may result in a falsely high prevalence of SIBO, due to the slow intestinal transit commonly seen in CF [22]. The hydrogen glucose breath test may result in a falsely high prevalence of SIBO, due to the slow intestinal transit commonly seen in CF [22].…”