What is the appropriate workup for abdominal bloating?

Workup for Abdominal Bloating

Begin with a focused clinical history and physical examination to identify alarm features, then reserve invasive testing exclusively for patients with red flags—most patients with isolated bloating require minimal or no diagnostic testing. 1, 2

Initial Clinical Assessment

Key History Elements to Elicit

• Alarm features that mandate immediate investigation: unintentional weight loss, gastrointestinal bleeding, persistent vomiting, iron-deficiency anemia, family history of GI malignancy 2
• Age and sex considerations: In women ≥50 years, maintain high suspicion for ovarian cancer, as bloating is often a presenting symptom 2, 3
• Bowel habits: Straining with soft stool, digital disimpaction, splinting, or fecal incontinence suggest pelvic floor disorders 1
• Associated symptoms: Nausea, vomiting, early satiety, or postprandial fullness may indicate gastroparesis or functional dyspepsia 1, 4
• Geographic and risk factors: High Helicobacter pylori prevalence regions, diabetes, prior gastric surgery, medication use (opioids, anticholinergics) 1, 4

Physical Examination Priorities

• Digital rectal examination to identify increased/decreased sphincter tone, pelvic floor dyssynergia, rectal prolapse, anal stricture, or rectocele 1, 3
• Assess for abdominal distention (objective increase in girth) versus subjective bloating sensation 3
• Evaluate hydration status, abdominal tenderness, and presence of distension 4

Diagnostic Testing Algorithm

First-Line Testing (Selective, Not Routine)

Order these tests ONLY if clinically indicated:

• Celiac disease serologic testing (tissue transglutaminase IgA + total IgA) in patients with bloating, particularly with diarrhea or weight loss 2
• Abdominal imaging and upper endoscopy are reserved exclusively for patients with alarm features, recent symptom worsening, or abnormal physical examination 1, 2, 3
• Upper endoscopy specifically in patients >40 years with dyspeptic symptoms in high H. pylori prevalence regions 2

Carbohydrate Intolerance Evaluation

Use a stepwise approach prioritizing cost-effectiveness:

• Start with dietary restriction trials as the simplest and most cost-effective first step 2
• Hydrogen/methane breath testing for lactose, fructose, or sucrose intolerance only after failed dietary trials 1, 2
• In a small subset of at-risk patients, consider small bowel aspiration and glucose- or lactulose-based breath testing for small intestinal bacterial overgrowth 1

Motility Studies (Highly Selective)

Do NOT order gastric emptying studies routinely for bloating alone. 1, 2, 3

Consider gastric emptying scintigraphy (4-hour protocol) only when:

• Nausea and vomiting are prominent symptoms 1, 2, 3
• Postprandial functional dyspepsia subtype is suspected 1

Reserve whole gut motility studies and antroduodenal manometry for:

• Refractory upper GI symptoms with severe bloating, distention, and weight loss 1
• Suspected intestinal neuromyopathic disorders based on supporting history 1
• Treatment-refractory lower GI symptoms warranting evaluation for neuromyopathic disorders 1

Anorectal Physiology Testing

Consider in specific populations:

• Women with IBS-C not responding to standard therapies 1
• Patients with suspected pelvic floor disorders based on history or examination findings 1, 3
• Bloating thought to be related to constipation or difficult evacuation 1, 3
• Confirm pelvic floor dyssynergia with anorectal physiology testing combined with balloon expulsion 1, 3

Rome IV Diagnostic Criteria

Use Rome IV criteria to diagnose primary abdominal bloating and distention in patients without alarm features or structural abnormalities. 1, 2, 3

Critical Pitfalls to Avoid

• Do not over-test functional bloating—the diagnostic yield is extremely low without alarm symptoms 2
• Do not miss ovarian cancer in women ≥50 years despite benign examination 2, 3
• Do not attribute all distention to gas accumulation—small increases in intraluminal gas (~10%) can trigger significant distention in patients with abnormal pelvic-diaphragmatic coordination 3
• Do not order routine probiotics—evidence does not support efficacy for abdominal bloating 3
• Approximately 40% of gastroparesis patients report bloating, but symptoms do not correlate with degree of gastric emptying delay, so avoid ordering gastric emptying studies based on bloating severity alone 1

When to Escalate Testing

Proceed with advanced evaluation only when:

• Alarm features are present at any point 1, 2
• Symptoms worsen despite conservative management 1, 2
• Physical examination becomes abnormal 1, 2
• Severe constipation coexists with upper GI symptoms (>30% of severe gastroparesis patients have delayed small bowel/colonic transit) 1