Original Contribution
The American Journal of Gastroenterology (2005) 100, 383–389; doi:10.1111/j.1572-0241.2005.40100.x
Visceral Sensitivity and Symptoms in Patients with Constipation- or Diarrhea-predominant Irritable Bowel Syndrome (IBS): Effect of a Low-Fat Intraduodenal Infusion
Maria Pia Caldarella MD1, Angelo Milano MD1, Francesco Laterza MD1, Flora Sacco MD1, Crysanthi Balatsinou MD1, Domenico Lapenna MD1, Sante Donato Pierdomenico MD1, Franco Cuccurullo MD1 and Matteo Neri MD1
1Department of Medicine and Ageing Sciences, Section of Internal Medicine and Gastroenterology; and the Centre of Excellence on Ageing, Gabriele D'Annunzio University and Foundation, Chieti, Italy
Correspondence: Matteo Neri, MD, Patologia Medica, Ospedale SS. Annunziata, 66100 Chieti, Italy
Received 22 January 2004; Revised 0000; Accepted 23 June 2004.
Abstract
BACKGROUND:
Visceral hypersensitivity is common in Irritable Bowel Syndrome (IBS) patients, and symptoms exacerbate postprandially. Yet the effects of nutrients on visceral sensitivity and symptoms in these patients have not been fully explored.
AIMS:
To evaluate the differences of visceral sensitivity and symptoms in healthy subjects and IBS patients during fasting and intraduodenal lipids infusion.
METHODS:
Graded rectal distensions at fixed tension levels were performed in 16 IBS patients (8 IBS-C and 8 IBS-D) and 6 healthy subjects before and during intraduodenal lipids infusion at 0.5 kcal/min. Tension levels were increased in 4 gr increments up to 64 gr or discomfort during both conditions. At each step, perception and symptoms were measured by means of a validated questionnaire.
RESULTS:
In basal conditions, perception thresholds in IBS patients and health were, respectively, 8 
2 gr versus 32 9 gr (p < 0.001) with no changes during lipids. Intraduodenal lipids infusion significantly lowered threshold of discomfort in IBS patients in comparison to fasting (24 6 gr vs 34 4 gr; p < 0.05), while health tolerated all distension without discomfort. No differences of compliance, perception, or discomfort were observed between the two subgroups of patients at each tension step. The predominant symptom elicited in patients with IBS-C was abdominal pain (54%), while patients with IBS-D exhibited urgency (63%, p < 0.005); this pattern was maintained during lipids.
CONCLUSIONS:
Intraduodenal lipids increase visceral sensitivity in both IBS-C and IBS-D; symptoms specificity in response to rectal distension is maintained in the postprandial period. Lipids may be responsible for the postprandial symptoms exacerbation in IBS.
