A pilot study on duodenal acid exposure and its relationship to symptoms in functional dyspepsia with prominent nausea.
BACKGROUND
Duodenal hypersensitivity to acid and decreased duodenal clearance of exogenous acid have been reported in functional dyspepsia (FD). However, the relevance of these abnormalities to spontaneous duodenal acid exposure and dyspeptic symptoms in FD is unknown.


OBJECTIVE
To determine spontaneous duodenal acid exposure and its relationship with symptoms, duodenal sensitivity to acid, and the effects of a 5-HT(3) receptor antagonist on duodenal responses to acid in FD.


METHODS
Eleven FD patients with prominent nausea and 11 healthy controls underwent 24-h ambulatory duodenal pH monitoring with assessment of dyspeptic symptoms. On the next day, duodenal bolus infusions of 5 ml of acid and normal saline were given in a randomized double-blind manner and repeated after ondansetron or a placebo.


RESULTS
Nighttime duodenal acid exposure was similar, but FD patients had lower duodenal pH and higher duodenal % time (pH < 4) than controls during the daytime and in the second postprandial 2 h (p < 0.05). Seven patients (64%) with duodenal acid exposure above the normal range had higher severity scores for several dyspeptic symptoms including nausea. However, the symptom severity was poorly or weakly correlated to duodenal pH, and brief duodenal acid infusion did not affect any symptoms. Duodenal responses to exogenous acid were unaffected by 5-HT(3) receptor antagonism.


CONCLUSIONS
Spontaneous duodenal acid exposure is increased in a subset of FD patients with prominent nausea, and this is associated with more severe dyspeptic symptoms. However, a direct relationship between duodenal acid exposure and symptom severity is lacking.
Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, University of Leuven, Herestraat 49, B-3000 Leuven, Belgium.
Kwang-Jae
KJ
Lee
Brunello
B
Demarchi
Ingrid
I
Demedts
Daniel
D
Sifrim
Petra
P
Raeymaekers
Jan
J
Tack
D000328:Adult; D016022:Case-Control Studies; D004311:Double-Blind Method; D004386:Duodenum / Q000187:drug effects* / Q000378:metabolism; D004415:Dyspepsia / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007263:Infusions, Parenteral; D007419:Intestinal Secretions / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D009853:Omeprazole / Q000008:administration & dosage*; D010865:Pilot Projects; D019518:Postprandial Period; D011336:Probability; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D009853:Omeprazole; D006851:Hydrochloric Acid