Bloating in constipation: relevance of intraluminal gas handling

DIAGNOSIS AND MANAGEMENT OF CHRONIC IDIOPATHIC CONSTIPATION: A NARRATIVE REVIEW FROM A BRAZILIAN EXPERT TASK FORCE

ABSTRACT Background Chronic idiopathic constipation (CIC) is a condition that widely affects the global population, represents relevant healthcare resource utilization and costs, and impacts the individual’s well-being. Objective To review the consensus of expert societies and published guidelines on the diagnosis and treatment of CIC in adults, seeking to assist reasoning and decision-making for medical management of patients with CIC and provide a practical reference material. Methods A Brazilian medical task force searched the scientific literature in the following electronic databases: MEDLINE/PubMed, SciELO, EMBASE and Cochrane, using the following descriptors: chronic constipation, diagnosis, management of chronic constipation. In addition, a review of articles on the mechanism of action, safety, and efficacy of therapeutic options available in Brazil was carried out. Results The diagnostic approach and the understanding of the pathophysiology present in CIC are essential items to indicate the appropriate therapy and to understand the ecosystem of the patient’s needs. Conclusion CIC is a common condition in adults, occurring more frequently in the elderly and in women. Proper management is defined by detailed medical history and physical examination, together with appropriate therapeutics, regardless pharmacological or not, and depending on the best moment of indication. This way, the impact on quality of life is also optimized.

Symptom severity and clinical characteristics of patients with bloating

BACKGROUND

Abdominal bloating is common in functional gastrointestinal disorders (FGID). To better characterize this patient population, we evaluated clinical and psychological characteristics of bloating and analyzed their differences by bloating severity.

METHODS

Patients with FGIDs evaluated at a single academic outpatient referral gastroenterology clinic were surveyed. Bloating severity was classified as minimal, moderate or severe. Symptom-specific questionnaires were used to evaluate bowel habits, abdominal bloating, depression, anxiety, somatization and sleep disturbance. Associations between bloating severity, clinical characteristics and FGID subtypes were analyzed in univariate and multivariate modeling.

KEY RESULTS

Of 612 FGID patients included (78% female, mean age of 44 ± 16.5 years), bloating was reported as minimal in 231(37.8%), moderate in 217(35.4%), or severe in 164(26.8%). Patients with severe bloating were more likely to be female, younger, and have co-existing functional dyspepsia than those with minimal bloating (p < 0.05). Bloating severity and severity of abdominal distension were significantly correlated (p < 0.05). On multivariable regression, patients who met criteria for functional constipation and functional dyspepsia had 80% and 125% higher odds, respectively, of severe bloating compared to minimal to moderate bloating. Younger age, abdominal pain and constipation severity, and somatization scores were also independently associated with severity of bloating.

CONCLUSIONS & INFERENCES

Severe bloating is associated with younger age, and with more severe abdominal pain, constipation, and somatization. Patients who met criteria for functional constipation and functional dyspepsia are more likely to experience severe bloating.

Chronic Constipation

Constipation is a common symptom that may be primary (idiopathic or functional) or associated with a number of disorders or medications. Although most constipation is self-managed by patients, 22% seek health care, mostly to primary care physicians (>50%) and gastroenterologists (14%), resulting in large expenditures for diagnostic testing and treatments. There is strong evidence that stimulant and osmotic laxatives, intestinal secretagogues, and peripherally restricted μ-opiate antagonists are effective and safe; the lattermost drugs are a major advance for managing opioid-induced constipation. Constipation that is refractory to available laxatives should be evaluated for defecatory disorders and slow-transit constipation using studies of anorectal function and colonic transit. Defecatory disorders are often responsive to biofeedback therapies, whereas slow-transit constipation may require surgical intervention in selected patients. Both efficacy and cost should guide the choice of treatment for functional constipation and opiate-induced constipation. Currently, no studies have compared inexpensive laxatives with newer drugs that work by other mechanisms.

Linaclotide in Chronic Idiopathic Constipation Patients with Moderate to Severe Abdominal Bloating: A Randomized, Controlled Trial

BACKGROUND

Abdominal bloating is a common and bothersome symptom of chronic idiopathic constipation. The objective of this trial was to evaluate the efficacy and safety of linaclotide in patients with chronic idiopathic constipation and concomitant moderate-to-severe abdominal bloating.

METHODS

This Phase 3b, randomized, double-blind, placebo-controlled clinical trial randomized patients to oral linaclotide (145 or 290 μg) or placebo once daily for 12 weeks. Eligible patients met Rome II criteria for chronic constipation upon entry with an average abdominal bloating score ≥5 (self-assessment: 0 10-point numerical rating scale) during the 14-day baseline period. Patients reported abdominal symptoms (including bloating) and bowel symptoms daily; adverse events were monitored. The primary responder endpoint required patients to have ≥3 complete spontaneous bowel movements/week with an increase of ≥1 from baseline, for ≥9 of 12 weeks. The primary endpoint compared linaclotide 145 μg vs. placebo.

RESULTS

The intent-to-treat population included 483 patients (mean age=47.3 years, female=91.5%, white=67.7%). The primary endpoint was met by 15.7% of linaclotide 145 μg patients vs. 7.6% of placebo patients (P<0.05). Both linaclotide doses significantly improved abdominal bloating vs. placebo (P<0.05 for all secondary endpoints, controlling for multiplicity). Approximately one-third of linaclotide patients (each group) had ≥50% mean decrease from baseline in abdominal bloating vs. 18% of placebo patients (P<0.01). Diarrhea was reported in 6% and 17% of linaclotide 145 and 290 μg patients, respectively, and 2% of placebo patients. AEs resulted in premature discontinuation of 5% and 9% of linaclotide 145 μg and 290 μg patients, respectively, and 6% of placebo patients.

CONCLUSIONS

Once-daily linaclotide (145 and 290 μg) significantly improved bowel and abdominal symptoms in chronic idiopathic constipation patients with moderate-to-severe baseline abdominal bloating; in particular, linaclotide significantly improved abdominal bloating compared to placebo, an important finding given the lack of agents available to treat abdominal bloating in chronic idiopathic constipation patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01642914.

Fasting and postprandial volumes of the undisturbed colon: normal values and changes in diarrhea-predominant irritable bowel syndrome measured using serial MRI

BACKGROUND

Previous assessments of colon morphology have relied on tests which were either invasive or used ionizing radiation. We aimed to measure regional volumes of the undisturbed colon in healthy volunteers (HV) and patients with diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

3D regional (ascending, transverse, and descending) colon volumes were measured in fasting abdominal magnetic resonance (MR) images of 75 HVs and 25 IBS-D patients. Thirty-five of the HV and all 25 IBS-D subjects were fed a standard meal and postprandial MRI data obtained over 225 min.

KEY RESULTS

Colonic regions were identified and 3D maps from cecum to sigmoid flexure were defined. Fasted regional volumes showed wide variation in both HVs being (mean ± SD) ascending colon (AC) 203 ± 75 mL, transverse (TC) 198 ± 79 mL, and descending (DC) 160 ± 86 mL with no difference from IBS-D subjects (AC 205 ± 69 mL, TC 232 ± 100 mL, and DC 151 ± 71 mL, respectively). The AC volume expanded by 10% after feeding (p = 0.007) in the 35 HV possibly due to increased ileo-colonic inflow. A later rise in AC volume occurred from t = 90 to t = 240 min as the meal residue entered the cecum. In contrast, IBS-D subjects showed a much reduced postprandial response of the AC (p < 0.0001) and a greater increase in TC volume after 90 min (p = 0.0244) compared to HV.

CONCLUSIONS & INFERENCES

We have defined a normal range of the regional volumes of the undisturbed colon in fasted and fed states. The AC in IBS-D appeared less able to accommodate postprandial inflow which may account for faster colonic transit.

Abdominal bloating: pathophysiology and treatment

Abdominal bloating is a very common and troublesome symptom of all ages, but it has not been fully understood to date. Bloating is usually associated with functional gastrointestinal disorders or organic diseases, but it may also appear alone. The pathophysiology of bloating remains ambiguous, although some evidences support the potential mechanisms, including gut hypersensitivity, impaired gas handling, altered gut microbiota, and abnormal abdominal-phrenic reflexes. Owing to the insufficient understanding of these mechanisms, the available therapeutic options are limited. However, medical treatment with some prokinetics, rifaximin, lubiprostone and linaclotide could be considered in the treatment of bloating. In addition, dietary intervention is important in relieving symptom in patients with bloating.

Intestinal microbiota, pathophysiology and translation to probiotic use in patients with irritable bowel syndrome

Probiotic agents have received growing attention in recent years as an alternative therapeutic tool in the management of irritable bowel syndrome. In this article, we will discuss the rationale that support this indication, including the role of intestinal microbiota in gastrointestinal function in both human and animal models, potential links between an impaired microbiota imbalance and the psycho-immunopathophysiology of irritable bowel syndrome, and the results of the available clinical trials to date.