Gastrointestinal sensory abnormalities in functional dyspepsia

Unrecognized Functional Dyspepsia Among Those With Refractory Chronic Constipation: Analysis of a Tertiary Cohort

BACKGROUND AND AIMS

Patients with functional constipation (FC) are frequently dissatisfied with current treatment options which may be related to persistent, unaddressed symptoms. We hypothesized that refractory FC may actually represent functional dyspepsia (FD) overlap. Among adults presenting with refractory FC, we sought to (1) identify the prevalence of concurrent FD and (2) identify the symptoms and presentations most frequently associated with concurrent FD and FC.

METHODS

We assembled a retrospective cohort of 308 patients sequentially presenting to a tertiary neurogastroenterology clinic for evaluation of refractory FC, defined as having failed first-line therapy. Using Rome IV criteria, trained raters identified the presence and characteristics of concurrent FD in addition to demographics, presenting complaints, and psychological comorbidities.

RESULTS

Among 308 patients presenting with refractory FC (average of 3.0 ± 2.3 constipation treatments tried unsuccessfully), 119 (38.6%) had concurrent FD. Aside from meeting FD criteria, the presence of concurrent FD was associated with patient complaints of esophageal symptoms (Odds ratio = 3.1; 95% confidence interval, 1.80-5.42) and bloating and distension (Odds ratio = 2.67; 95% confidence interval, 1.50-4.89). Patients with concurrent FD were more likely to have a history of an eating disorder (21.0% vs 12.7%) and were also more likely to present with current avoidant/restrictive food intake disorder-related symptoms (31.9% vs 21.7%).

CONCLUSION

Almost 40% of adult patients referred for refractory FC met criteria for concurrent FD in a tertiary-level cohort. The presence of both FC and FD was associated with greater esophageal symptoms and bloating/distention. Determining presence of concurrent FD may represent an additional therapeutic opportunity in refractory patients who may attribute symptoms to FC alone.

Epidemiology of upper gastrointestinal symptoms in Brazil (EpiGastro): A population-based study according to sex and age group

AIM: To determine the prevalences of symptoms consistent with gastroesophageal reflux disease (GERD) and dyspepsia in South America.

METHODS: A telephone survey was conducted among adult owners of land-based telephones in São Paulo, Brazil, using previously validated computer-assisted sampling and survey protocols. The Portuguese-language survey included (1) sociodemographic characteristics (e.g., weight, height, smoking) and comorbidities; (2) dietary habits; (3) presence of symptoms consistent with GERD or dyspepsia within the prior 3 mo; and (4) use of medications and other therapies to manage symptoms. Data were stratified post-hoc into three homogeneous geographical regions of São Paulo according to the Social Exclusion Indices of the districts and postal codes. Survey response data from each respondent were weighted by the numbers of adults and landline telephones in each household. The analyses were weighted to account for sampling design and to be representative of the São Paulo population according to city census data.

RESULTS: Among 4570 households contacted, an adult from 3050 (66.7%) agreed to participate. The nonresponse rate was 33.3%. The mean (SE) respondent age was 42.6 (16.0) years. More than half of all respondents were women (53.1%), aged 18 through 49 years (66.7%), married or cohabitating (52.5%), and/or above normal-weight standards (i.e., 35.3% overweight and 16.3% obese). A total of 26.5% of women were perimenopausal. More than 20% of respondents reported highly frequent symptoms consistent with GERD (e.g., gastric burning sensation = 20.8%) or dyspepsia (e.g., abdominal swelling/distension = 20.9%) at least once per month. Prevalences of these symptoms were significantly (approximately 1.5- to 2.0-fold) higher among women than men but did not vary significantly as a function of advancing age. For instance, 14.1% of women reported that they experienced stomach burning (symptom of GERD) at least twice per week, compared to 8.4% of men (P = 0.012 by χ² test). A total of 15.7% of women reported that they experienced abdominal swelling (symptom of dyspepsia) at least twice per week, compared to 6.4% of men (P < 0.001 by χ² test). Despite frequent manifestations of GERD or dyspepsia, most (≥ 90%) respondents reported that they neither received prescription medications from physicians, nor took behavioral measures (e.g., dietary modifications), to manage symptoms.

CONCLUSION: Symptoms consistent with dyspepsia and GERD are prevalent in Brazil and represent major public-health and clinical challenges.

Effects and mechanisms of gastric electrical stimulation on visceral pain in a rodent model of gastric hyperalgesia secondary to chemically induced mucosal ulceration

BACKGROUND

Gastric electrical stimulation (GES) has been suggested as a potential treatment for patients with gastric motility disorders. The aim of this study was to examine the effects and mechanisms of GES on visceral pain in awaken rats.

METHODS

Under anesthesia, acetic acid was injected into the submucosal layer of the stomach wall in Sprague-Dawley (SD) male rats. Each rat was chronically placed with an intragastric balloon and two pairs of electrodes on gastric serosa for GES and at the neck muscles for electromyography (EMG) recordings respectively. The study was composed of four experiments. Exp 1 was designed to determine optimal GES parameters in reducing EMG response to gastric distention (GD). Exp 2 was performed to investigate the effect of GES on gastric tone/accommodation. Exp 3 was to investigate if the opioid pathway was involved in the analgesic effects of GES. Exp 4 was to assess the effectiveness of GES on the spinal cord neurons (T9-T10) responding to GD.

KEY RESULTS

(i) Gastric electrical stimulation with a train on of 0.1 s and off of 0.4 s, 0.25 ms, 100 Hz, and 6 mA significantly reduced GD-induced EMG responses at GD 40, 60, and 80 mmHg. (ii) The inhibitory effects of GES on the GD-induced EMG responses were blocked by Naloxone. (iii) GES inhibited 90% of high-threshold (HT) spinal neurons in response to GD. However, GES with the same parameters only suppressed 36.3% low-threshold (LT) neuronal response to GD.

CONCLUSIONS & INFERENCES

Gastric electrical stimulation with optimal parameters inhibits visceral pain; the analgesic effect of GES on visceral pain is mediated via the endogenous opioid system and the suppression of spinal afferent neuronal activities.

Pancreatic insulin and exocrine secretion are under the modulatory control of distinct subpopulations of vagal motoneurones in the rat

Brainstem vago-vagal neurocircuits modulate upper gastrointestinal functions. Derangement of these sensory-motor circuits is implicated in several pathophysiological states, such as gastroesophageal reflux disease (GERD), functional dyspepsia and, possibly, pancreatitis. While vagal circuits controlling the stomach have received more attention, the organization of brainstem pancreatic neurocircuits is still largely unknown. We aimed to investigate the in vitro and in vivo modulation of brainstem vagal circuits controlling pancreatic secretion. Using patch clamp techniques on identified vagal pancreas-projecting neurones, we studied the effects of metabotropic glutamate receptor (mGluR) agents in relation to the effects of exendin-4, a glucagon-like peptide 1 analogue, cholecystokinin (CCK) and pancreatic polypeptide (PP). An in vivo anaesthetized rat preparation was used to measure pancreatic exocrine secretion (PES) and plasma insulin following microinjection of metabotropic glutamate receptor (mGluR) agonists and exendin-4 in the brainstem. Group II and III mGluR agonists (2R,4R-4-aminopyrrolidine-2,4-dicarboxylate (APDC) and L(+)-2-amino-4-phosphonobutyric acid (L-AP4), respectively) decreased the frequency of miniature inhibitory and excitatory postsynaptic currents (mIPSCs and mEPSCs, respectively) in the majority of the neurones tested. All neurones responsive to L-AP4 were also responsive to APDC, but not vice versa. Further, in neurones where L-AP4 decreased mIPSC frequency, exendin-4 increased, while PP had no effect upon, mIPSC frequency. Brainstem microinjection of APDC or L-AP4 decreased plasma insulin secretion, whereas only APDC microinjections increased PES. Exendin-4 microinjections increased plasma insulin. Our results indicate a discrete organization of vagal circuits, which opens up promising avenues of research aimed at investigating the physiology of homeostatic autonomic neurocircuits.

Gender-related differences in dyspepsia: a qualitative systematic review

BACKGROUND

Relative to men, women are diagnosed more frequently with functional gastrointestinal (GI) disorders. With increased awareness of basic gender differences in perception and treatment of visceral pain, there has been new interest in research on gender disparity in the care of people with functional GI disorders. Past attention has focused on irritable bowel syndrome, whereas gender differences in other disorders are less well described.

OBJECTIVE

Our aim was to systematically review studies that have examined gender-related differences among patients with dyspepsia.

METHODS

MEDLINE, HealthSTAR, and PsycINFO databases were searched for English-language articles on dyspepsia published between 1966 and August 2001. Epidemiologic studies, clinical trials, review articles, and conceptual articles from peer-reviewed journals were included for review. Findings were summarized and discussed within a framework of biological and psychosocial factors. Statistical analysis of combined data was inappropriate because of the inconsistent definition of dyspepsia among different studies and wide variation in the types of articles reviewed.

RESULTS

Studies that examine gender-related differences in patients with dyspepsia have focused their investigations on the clinical epidemiology and pathophysiology of dyspepsia. In most epidemiologic studies, no gender analysis was performed beyond a description of sample demographics, and when statistical significance was tested, few consistent gender differences were found. Overall, it appears that men and women with dyspepsia possibly differ with respect to pattern of symptoms, pain perception or modulation, and antinociceptive mechanisms, but these observations have not been confirmed. No study evaluated the clinical implications of these possible differences.

CONCLUSIONS

Future efforts should be directed to not only examine gender-related differences in the clinical epidemiology of dyspepsia, but also understand their clinical significance. Therefore, well-designed population-based studies using a consistent definition of dyspepsia are needed to investigate the prevalence of dyspepsia symptoms and patterns of dyspepsia management among men and women.

Acid-sensing properties in rat gastric sensory neurons from normal and ulcerated stomach

Gastric acid contributes to dyspeptic symptoms, including abdominal pain, in patients with disorders of the proximal gastrointestinal tract. To examine the molecular sensor(s) of gastric acid chemonociception, we characterized acid-elicited currents in dorsal root ganglion (DRG) and nodose ganglion (NG) neurons that innervate the stomach and examined their modulation after induction of gastric ulcers. A fluorescent dye (DiI) was injected into the stomach wall to retrogradely label gastric sensory neurons. After 1-2 weeks, gastric ulcers were induced by 45 s of luminal exposure of the stomach to 60% acetic acid injected into a clamped area of the distal stomach; control animals received saline. In whole-cell voltage-clamp recordings, all gastric DRG neurons and 55% of NG neurons exhibited transient, amiloride-sensitive, acid-sensing ion-channel (ASIC) currents. In the remaining 45% of NG neurons, protons activated a slow, sustained current that was attenuated by the transient receptor potential vanilloid subtype 1 antagonist, capsazepine. The kinetics and proton sensitivity of amiloride-sensitive ASIC currents differed between NG and DRG neurons. NG neurons had a lower proton sensitivity and faster kinetics, suggesting expression of specific subtypes of ASICs in the vagal and splanchnic innervation of the stomach. Effects of Zn2+ and N,N,N',N'-tetrakis-(2-pyridylmethyl)-ethylenediamine on acid-elicited currents suggest contributions of ASIC1a and ASIC2a subunits. Gastric ulcers altered the properties of acid-elicited currents by increasing pH sensitivity and current density and changing current kinetics in gastric DRG neurons. The distinct properties of NG and DRG neurons and their modulation after injury suggest differential contributions of vagal and spinal afferent neurons to chemosensation and chemonociception.

Dyspepsia consulters and patterns of management: a population-based study

BACKGROUND

Although dyspepsia is common, management patterns in the United States are unknown.

AIM

To determine the pattern of dyspepsia evaluation and treatment over 20 years in a population-based cohort, and test the hypothesis that the management was influenced by dyspepsia subgroup and gender.

METHODS

The validated Bowel Disease Questionnaire was mailed to a random sample of Olmsted County, Minnesota residents (1988-1990). Of the 835 survey respondents, 213 subjects were identified as having dyspepsia according to Rome I Criteria. The medical chart of each dyspeptic subject who had not denied research authorization (n = 206) was reviewed to identify all episodes of care for dyspepsia symptoms 10 years before and 10 years after the date the Bowel Disease Questionnaire was completed. Of these 206 subjects (mean age 47 years, 48% female), 34% had ulcer-like dyspepsia, 32% had dysmotility-like dyspepsia, and 37% had reflux-like dyspepsia.

RESULTS

Nearly half (n = 98, 48%) had episodes of care for dyspepsia symptoms over 20 years. Of these 98 subjects, 49% had upper gastrointestinal endoscopy, 4% motility studies and 12% were tested for Helicobacter pylori. At the first visit of the episode of care closest to Bowel Disease Questionnaire completion, 72% were seen in primary care, 16% in emergency medicine and 2% in gastroenterology. In addition, 13% were referred to gastroenterology clinic within this episode. During the study period, 70% were given an 'acid' diagnosis, 7% a 'motility' diagnosis and 54% a 'functional' diagnosis; 78% received acid suppression agents (28% proton pump inhibitors), 18% psychotropic agents and 7% prokinetic agents. No significant association was found between gender and test usage, specialty referral or type of treatment, although women were three times less likely to receive proton pump inhibitors (odds ratio 3.3, 95% CI: 1.2-9.1). Symptom severity, frequency and pattern were risk factors for health care seeking in dyspepsia.

CONCLUSIONS

Delivery of care for dyspepsia was similar among dyspepsia subgroups and in men and women.

Experimentally induced ulcers and gastric sensory-motor function in rats

Prior studies have demonstrated that inflammation can sensitize visceral afferent neurons, contributing to the development of hyperalgesia. We hypothesized that both afferent and efferent pathways are affected, resulting in changes in motor and sensory function. Kissing ulcers (KU) were induced in the distal stomach by injecting 60% acetic acid for 45 s into a clamped area of the stomach. In controls, saline was injected into the stomach. A balloon catheter was surgically placed into the stomach, and electromyographic responses to gastric distension were recorded from the acromiotrapezius muscle at various times after ulcer induction. The accommodation reflex was assessed by slowly infusing saline into the distally occluded stomach. Gastric pressure changes in response to vagal stimulation were measured in anesthetized rats. Contractile function of circular muscle strips was examined in vitro using force-displacement transducers. KU caused gastric hypersensitivity that persisted for at least 14 days. Fluid distension of the stomach led to a rapid pressure increase in KU but not in control animals, consistent with an impaired accommodation reflex. Gastric ulcers enhanced the contractile response to vagal stimulation, whereas the effect of cholinergic stimulation on smooth muscle in vitro was not changed. These data suggest that inflammation directly alters gastric sensory and motor function. Increased activation of afferents will trigger vagovagal reflexes, thereby further changing motility and indirectly activating sensory neurons. Thus afferent and efferent pathways both contribute to the development of dyspeptic symptoms.

Characteristics of patients with erosive and nonerosive GERD in high-Helicobacter-pylori prevalence region

It is still not known whether there are differences between erosive and nonerosive GERD. The aim of the present study is to evaluate the prevalence of Helicobacter pylori (HP) infection, and other differences between erosive and nonerosive gastroesophageal reflux disease (NERD) patients. One-hundred and four consecutive GERD patients (mean age: 41.6 +/- 12.3 years) were interviewed, endoscoped and tested for HP. Erosive GERD was defined according to the Los Angeles classification. Patients who had no erosions in the esophagus but complained of heartburn or/and acid regurgitation at least twice a week and for whom these symptoms had a negative impact on daily activities were considered to be NERD patients. Erosive GERD was identified in 53 (51%) patients (mean age: 41.0 +/- 12.7 years) and NERD in 51 (49.0%) patients (mean age: 42.2 +/- 11.9 years). HP infection was found in 32 (60.4%) erosive GERD patients, and 41 (80.4%) NERD patients, P < 0.05. Multivariate analysis revealed that there were two statistically significant prediction factors for NERD: female sex with odds ratio (OR) of 6.34 (95% CI: 2.41-16.64; P = 0.0002) and HP infection with odds ratio (OR) of 3.28 (95% CI: 1.26-8.58; P = 0.015). The presence of HP and female sex are found to be statistically significant predictors of NERD.

Impact of coexisting irritable bowel syndrome on symptoms and pathophysiological mechanisms in functional dyspepsia

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS).

AIM

The aim of the present study was to investigate whether coexisting IBS is also associated with symptom pattern or pathophysiology in FD.

METHODS

In 309 consecutive FD patients (207 women, age 42 +/- 0.8 yr), questionnaires were used to assess the dyspepsia symptom pattern and the Rome II criteria for IBS. The overall symptom severity was calculated adding the severity score (0-3, 0 = absent, 3 = severe) of eight dyspepsia symptoms. All patients underwent Helicobacter pylori testing, gastric barostat to determine sensitivity to distention and accommodation to a meal, and gastric emptying breath test.

RESULTS

Fifty-four percent of the patients had FD alone, whereas 46% had FD + IBS. FD + IBS patients were more likely to be female (75%vs 60%, p < 0.01) and to have a greater weight loss (5.4 +/- 0.6 vs 3.5 +/- 0.4 kg, p < 0.05). Coexisting IBS did not increase the risk of having any of the dyspeptic symptoms but the overall symptom severity was significantly higher in FD + IBS (12.4 +/- 0.4 vs 9.8 +/- 0.3, p < 0.01). FD + IBS patients had a lower threshold for first perception (2.9 +/- 0.3 vs 3.8 +/- 0.3 mmHg, p < 0.05) and for discomfort (7.9 +/- 0.4 vs 9.5 +/- 0.5 mmHg, p < 0.05) and a greater prevalence of hypersensitivity to gastric distention (44%vs 28%, p < 0.05). Gastric emptying, accommodation to a meal, and prevalence of H. pylori infection did not differ in the two groups.

CONCLUSION

About half of the FD patients fulfill the Rome II criteria for IBS. FD + IBS is more prevalent in female patients and is associated with a higher weight loss, with greater overall symptom severity, and with hypersensitivity to distention.

Psychosocial factors and perceived severity of functional dyspeptic symptoms: a psychosocial interactionist model

OBJECTIVE

A psychosocial interactionist model was presented to provide a systematic account of individual differences in perceived functional dyspeptic symptom severity.

METHODS

In a population-based survey, 4038 Hong Kong subjects (age 18-80 years) were interviewed. Five hundred ninety interviewees (14.6%) met the diagnostic criteria for functional dyspepsia (FD), and 396 of them participated in this study.

RESULTS

Results from multiple regression analyses revealed significant main effects of monitoring, emotional support, and coping flexibility on perceived FD symptom severity. A significant emotional support by coping flexibility interaction effect was also found.

CONCLUSIONS

The present findings provided support for the psychosocial interactionist model in showing that (1) monitoring is a risk factor related to greater perceived symptom severity, (2) emotional support and coping flexibility are resource factors related to lower perceived symptom severity, and (3) the beneficial role of emotional support is present only among those higher in coping flexibility but not among those lower in coping flexibility.

Gastric mucosal mast cells are increased in Helicobacter pylori-negative functional dyspepsia

BACKGROUND & AIMS

Mast cells might be involved in pathogenesis of functional dyspepsia because they can release a wide range of potent mediators, capable of altering gastric nerve and muscle function. This study aimed to determine whether mast cell numbers were increased in the gastric mucosa of patients with functional dyspepsia compared to control subjects.

METHODS

Biopsy samples were taken from the antrum and corpus of 111 patients: 20 asymptomatic control subjects, 62 patients with Rome criteria functional dyspepsia (33 Helicobacter pylori positive, 29 H. pylori negative), and 29 inflammatory control subjects (H. pylori positive). Mast cells were detected immunohistochemically by using a mouse monoclonal antibody specific for tryptase. Quantification was performed with light microscopy, and results were expressed as mast cells/mm(2) +/- standard error of mean.

RESULTS

Mast cells were significantly increased in H. pylori negative functional dyspepsia samples compared to normal control samples in the antrum (230.1 +/- 11.3 vs. 94.8 +/- 8.4, P < 0.001) and corpus (264.1 +/- 27.1 vs. 123.9 +/- 11.5, P = 0.001). Mast cells were also significantly increased in the antrum of patients with H. pylori positive functional dyspepsia compared to asymptomatic control subjects (166.5 +/- 17.0 vs. 94.8 +/- 8.4, P < 0.03). However, there was no significant difference between mast cell numbers in patients with H. pylori positive functional dyspepsia compared to inflammatory control subjects.

CONCLUSIONS

Mast cells are increased in functional dyspepsia, independently of inflammation. This might contribute to the pathogenesis of functional dyspepsia by altering signaling in the brain-gut axis.

A randomized controlled trial of psychotherapy in patients with chronic functional dyspepsia

BACKGROUND & AIMS

This study aimed to determine whether brief psychodynamic-interpersonal (PI) psychotherapy is more efficacious than a psychological control for patients with chronic, intractable functional dyspepsia (FD), and whether patients with abnormal gastric function respond differently than those with normal gastric function.

METHODS

Ninety-five consecutive patients with chronic symptoms of FD who had failed to respond to conventional pharmacologic treatments were approached. Thirty-seven received PI psychotherapy, and 36 the control condition (supportive therapy). Patients completed self-report questionnaires before and after treatment and 12 months later. The patients' gastroenterologists, who were blind to the study groups, conducted independent ratings before and after treatment. Forty-nine patients also underwent a radioisotope gastric emptying study. An intention-to-treat analysis was used with baseline scores as covariates.

RESULTS

At the end of treatment, there were significant advantages for PI psychotherapy compared with controls for the gastroenterologists' (P = 0.002) and patients' total symptom score (P = 0.015). One year after treatment, the symptomatic scores were similar. However, a subanalysis showed that PI therapy was superior to the control condition at 1 year, when patients with severe heartburn were excluded. There was no difference in outcome between patients with normal and abnormal gastric emptying.

CONCLUSIONS

PI therapy may have both short- and long-term effects in patients with dyspepsia, but further evaluation is required. Its cost-effectiveness needs to be determined.

Common functional gastrointestinal disorders: nonulcer dyspepsia and irritable bowel syndrome

Up to 35% of the world population suffer from functional gastrointestinal disorders (FGD), accounting for about 40% of gastroenterologic and 12% of primary care practice. Society incurs high costs from FGD morbidity in terms of medical workups and absenteeism from work. FGD are characterized by chronic and recurrent symptoms of the gastrointestinal (GI) tract without detectable structural or biochemical abnormalities. In the absence of universal biologic markers, the diagnosis is based on consensus symptom criteria (1). This chapter reviews current knowledge of the pathophysiology and provides a practical approach to patients with functional dyspepsia and irritable bowel syndrome, 2 of the most common functional GI syndromes.

Nonulcer dyspepsia

Nonulcer dyspepsia, characterized by unexplained persistent or recurrent epigastric pain or discomfort, affects approximately 20% of the general population. Symptom-based diagnostic criteria, first developed by an international group of experts, have been refined in the past year in an effort to increase the applicability of the criteria (Rome II criteria). New disease-specific questionnaires that were developed to measure quality of life in patients with dyspepsia are now available and are expected to be widely used in clinical research studies. Studies on the pathophysiology and management of nonulcer dyspepsia were other major topics in the past year, including three large, well-conducted randomized controlled trials of Helicobacter pylori eradication and symptom resolution.