What is the management of abdominal distension?

Management of Abdominal Distension

Immediate Triage: Acute vs. Chronic Presentation

The first critical decision is determining whether abdominal distension represents an acute surgical emergency requiring immediate intervention or a chronic functional disorder amenable to medical management. 1

Acute Presentation Requiring Emergency Evaluation

If the patient presents with acute onset distension plus peritoneal signs (guarding, rebound tenderness), hemodynamic instability, or severe pain, immediate surgical consultation is mandatory 1:

• Initiate NPO status, IV fluid resuscitation, nasogastric tube decompression, broad-spectrum antibiotics, and serial lactate monitoring 1
• Order plain abdominal radiographs immediately looking for "coffee bean sign" (sigmoid volvulus) or free air (perforation) 1
• Obtain CT scan with IV contrast urgently if plain films are non-diagnostic or if bowel ischemia/perforation is suspected 2, 1
• Never assume absence of peritonitis means absence of ischemia—lactate levels and serial examinations are essential 1

Critical laboratory testing must include: complete blood count, blood gas and lactate levels, electrolytes and renal function, C-reactive protein, and liver function tests 1. Elevated lactate with peritoneal signs indicates bowel ischemia requiring emergency surgery 1.

Chronic/Subacute Presentation

For patients with chronic or recurrent distension without alarm features, proceed with systematic evaluation below.

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Diagnostic Algorithm for Chronic Abdominal Distension

Step 1: Assess for Constipation

If constipation is present, use Rome IV criteria to diagnose IBS-C or chronic constipation 2:

• Perform anorectal manometry to diagnose pelvic floor dyssynergia, which is present in a significant proportion of patients with distension and difficult evacuation 2
• Biofeedback therapy is effective for bloating and distension when pelvic floor disorder is identified 2

Step 2: Evaluate for Food Intolerances

The simplest and most economically sound approach is a 2-week dietary restriction trial 2:

• Lactose intolerance (51% prevalence) and fructose intolerance (60% prevalence) are common across all disorders of gut-brain interaction 2
• If dietary restriction fails, consider hydrogen-based breath testing with glucose or lactulose for carbohydrate malabsorption 2
• Test for celiac disease with tissue transglutaminase IgA and total IgA levels in patients with IBS-D or alarm symptoms (weight loss, iron-deficiency anemia) 2
• Small bowel biopsy is required to confirm celiac disease if serology is positive 2

Step 3: Rule Out Small Intestinal Bacterial Overgrowth (SIBO)

SIBO should be suspected in high-risk patients: those with chronic watery diarrhea, malnutrition, weight loss, or systemic diseases causing small bowel dysmotility (cystic fibrosis, Parkinson disease) 2:

• Hydrogen-based breath testing with glucose or lactulose is the preferred diagnostic approach 2
• Small bowel aspirates are an alternative but more invasive 2
• Rifaximin is the most studied antibiotic for SIBO, though not FDA-approved for this indication; systemically absorbed alternatives include amoxicillin, fluoroquinolones, and metronidazole 2

Step 4: Consider Imaging and Endoscopy (Selective Use Only)

Abdominal imaging and upper endoscopy should be ordered only in patients with alarm features, recent worsening symptoms, or abnormal physical examination 2:

• Alarm features include: vomiting, weight loss >10%, GI bleeding, family history of IBD 2
• CT/MRI or abdominal ultrasound to exclude structural abnormalities 2
• Gastric emptying studies should not be ordered routinely for bloating and distension, but may be considered if nausea and vomiting are prominent 2

Step 5: Diagnose Primary Functional Bloating/Distension

Use Rome IV criteria to diagnose functional abdominal bloating and distension after excluding organic causes 2:

• Abdominophrenic dyssynergia (APD): distension not explained by increased intestinal gas, worse after meals 2
• Visceral hypersensitivity: abdominal pain with severe bloating 2

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Treatment Algorithm

Dietary Modifications (First-Line)

A gastroenterology dietitian should preferably monitor dietary treatment 2:

• Low FODMAP diet reduces bacterial fermentation and gas production, but should not be used in malnourished individuals 2
• Simple fiber reduction can decrease abdominal distension by reducing bacterial fermentation 2
• Peppermint oil may help with distension and pain 2

Pharmacologic Management

For constipation-predominant distension:

• Medications used to treat constipation should be considered if constipation symptoms are present 2
• Osmotic laxatives, stimulant laxatives, or secretagogues (linaclotide) 2, 3

For pain and spasm:

• Antispasmodics (otilonium bromide, peppermint oil, hyoscine butylbromide) for gastrointestinal smooth muscle spasm 2, 3
• Hyoscine butylbromide is poorly absorbed orally; intramuscular preparations may be more effective for long-term use 2

For SIBO:

• Rifaximin is the most studied antibiotic, though expensive and not FDA-approved for SIBO 2
• Alternative antibiotics include amoxicillin, fluoroquinolones, and metronidazole 2

For visceral hypersensitivity:

• Central neuromodulators (antidepressants) reduce visceral hypersensitivity, raise sensation threshold, and improve psychological comorbidities 2
• Options include tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and buspirone 3

Probiotics should not be used to treat abdominal bloating and distention 2.

Behavioral and Physical Therapies

For abdominophrenic dyssynergia:

• Diaphragmatic breathing and central neuromodulators are the primary treatments 2
• Speech therapy may also be beneficial 2

For functional bloating with IBS:

• Psychological therapies (hypnotherapy, cognitive behavioral therapy, brain-gut behavioral therapies) are effective 2
• Biofeedback therapy is effective when pelvic floor disorder is identified 2

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Critical Pitfalls to Avoid

• Never attribute chronic symptoms solely to functional disorders without excluding channelopathies, especially with family history of sudden cardiac death 1
• Avoid high-dose opioids and cyclizine in chronic dysmotility; consider narcotic bowel syndrome and supervised withdrawal 1
• Do not delay diagnostic laparoscopy if there is high clinical suspicion and alarming signs, even with negative radiological assessment 2
• Complete absence of bowel sounds indicates paralytic ileus, not mechanical obstruction; manage conservatively with NGT decompression, electrolyte correction, and minimizing opioids 1, 4