© Springer International Publishing Switzerland 2017
Bobby Desai and Alpa Desai (eds.)Primary Care for Emergency Physicians10.1007/978-3-319-44360-7_1616. Bloating
(1)
Emergency Medicine, University of Florida, Gainesville, FL, USA
(2)
Community Health and Family Medicine, University of Florida, Newberry, FL, USA
Keywords
BloatingAbdominal painFunctional bloatingGas transitGas production16.1 Introduction
Bloating is a bothersome complaint that is commonly reported to physicians; it ranks second to only abdominal pain in frequency of complaint to physicians [3]. It is estimated that around 11 % of the general population report frequent bloating [1], while in another study, 31 % of patients met the Rome I criteria for functional bloating [5]. In fact, 90 % of patients with a diagnosis of irritable bowel syndrome will report symptoms of bloating [6]. Unfortunately, bloating is a nonspecific term that relates to the patient’s subjective sensation of their abdominal distention, fullness or excessive gas, and the physician’s objective determination of true abdominal distention [2]. Furthermore, abdominal bloating is present in multiple functional abdominal disorders which include both non-emergent and emergent processes. When bloating is not part of another functional gastrointestinal process, it is included in the Rome III criteria as “functional bloating” [source]. The Rome III criteria for functional bloating include the repeated feeling of bloating or a noticeable abdominal distention for at least 3 days per month, onset of symptoms for at 6 months prior to diagnosis along with the presence of symptoms for at least 3 months, and inability to diagnose dyspepsia, irritable bowel syndrome, or another functional gastrointestinal disorder [7].
Since the natural history of bloating is poorly understood, diagnosis of this entity is sometimes difficult to the inability of the clinical to identify measureable parameters for assessment and grading, and, in many instances, bloating lacks a clear pathophysiologic explanation and a singular management strategy which makes the entity a quandary for physicians. Unfortunately, bloating can cause significant patient distress and concern which may prompt a subsequent presentation to the emergency department (ED). In fact, in those patients who did not have a diagnosis of irritable bowel syndrome, three-fourths described their symptoms as moderate to severe, and 50 % reduced their daily activities due to the symptoms of bloating [8].
16.2 Pathophysiology
The pathophysiology of this disorder is complicated and relies on the understanding on a multitude of factors. These include the natural production of gas within the gastrointestinal tract (GIT), the role of gut microflora, transit time of intestinal contents, and, finally, neuronal functional with the GIT [9]. Furthermore, there are different theories on bloating etiology that range from an increase in luminal contents ranging from fat, liquids, gas, and stools to an impairment of abdominal emptying to an alteration in intra-abdominal volume displacement (also known as the abdomino-phrenic theory) or increased intestinal stimuli due to the use of specific treatments or medications. These include antibiotics, probiotics, prokinetic agents, medications for spasm and gas reduction, and tricyclic antidepressants [4].
16.2.1 Intestinal Gas Production
The normal individual has approximately 100–200 cc of gas within the gastrointestinal tract, which increases after eating, especially in the colon. Stomach distention and corresponding small bowel stimulation subsequent to eating can accelerate the transit of gas; lipids, however, can cause the retention of gas, especially within the early small bowel [10, 11]. Gas production in the colon occurs primarily through bacterial metabolism, especially those foods that are not completely digested within the small intestine, including sugars such as lactose and fructose [14]. Other foods such as legumes and complex carbohydrates are metabolized within the colon. Additional sources of gas within the GI tract include the swallowing of air, ingestion of carbonated beverages, and acid/alkali neutralization in the upper GIT [12, 13]. Furthermore, the small intestine readily absorbs carbon dioxide which may be promptly consumed by some colonic bacterial species which also consume hydrogen. Thus, the total amount of gas in the intestine is ever in flux due to the normal passing of flatus; healthy patients tolerate intestinal gas easily due to the efficient evacuation.
Even though an excessive volume of intestinal gas has been proposed as a mechanism for bloating and distention, the vast majority of studies do not support this theory [15]. Infusion of a large amount of gas into the intestinal tract of healthy volunteers produced only small changes in abdominal girth, whereas patients with IBS show large changes in abdominal girth even in the absence of gas infusion [17]. While it is known that increased gas volumes are present in IBS patients compared to controls, there is a poor correlation between intra-abdominal gas contents and bloating [16]. Therefore, it has been theorized that the impaired transit of gas or an abnormal distribution of gas may be more problematic.
16.2.2 Impairment of Gas Transit
Studies have shown that patients with IBS have abnormalities in intestinal transit which may cause the symptoms of gas and bloating. Patients with IBS-related constipation have an increased prevalence of abdominal distention and bloating. Furthermore, in the study of gas infusion noted above, patients with IBS experienced more during the infusion than healthy volunteers. Furthermore, in another study of IBS patients subsequent to gas infusion, 90 % of IBS patients developed intestinal gas retention compared to control subjects [17]. The amount of abdominal distension correlated with gas retention in these patients. IBS patients also had impaired gas clearance from both the small intestine and proximal (not distal) colon [18].
16.2.3 Impaired Evacuation
The ineffective evacuation of gas results in gas retention and the symptom of pain with abdominal bloating. Specific patients, especially those with IBS, constipation, and functional bloating, have difficulty effectively evacuating gas and more likely to develop symptoms of abdominal distention [19].
16.2.4 Other Potential Causes
These include the unconscious changing of body position to a more lordotic one, abnormal abdominal-diaphragmatic reflexes where the diaphragms of specific patients descend while the ventral muscles relax which leads to a subsequent abdominal girth [20], and abnormal sensation or perception where patients with IBS are more sensitive to stretch and distention [21].
16.3 Risk Factors
Females
Especially during menstruation
Younger age
Presence of functional gastrointestinal disorder
Irritable bowel syndrome
Dyspepsia
Higher Somatic Symptom Checklist score
History of cholecystectomy
In terms of functional bloating
History of hysterectomy
In terms of functional bloating
History of abdominal surgery
For organic bloating
16.4 Differential Diagnosis
Abnormal colonic transit
Acute or subacute bowel ischemia
Aerophagia
Anorexia and bulimia
Bacterial overgrowth in the small bowel
Celiac disease
Changes or disturbances to colonic microflora
Constipation
Acute or chronic
Dietary
Increased carbohydrate intake
Consumption of nonabsorbable sugars
Sorbitol
Lactose intolerance
Intolerance to fructose
Sensitivity to gluten
Disorders of the pelvic floor
Diverticulosis
Small or large bowel
Enteropathogenic infections
Functional bloating
Functional dyspepsia
Gastroparesis
Gastric outlet obstructionRelated posts:
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