What is the best approach for assessing abdominal distention?

Best Approach for Assessing Abdominal Distention

The best approach for assessing abdominal distention is to use Rome IV criteria for diagnosis, followed by targeted evaluation for abdominophrenic dyssynergia (APD) using abdominothoracic wall motion assessment. 1

Diagnostic Approach

Initial Assessment

• Use Rome IV criteria to diagnose primary abdominal bloating and distention, which provides standardized diagnostic parameters 1
• Differentiate between true abdominal distention (objective increase in abdominal girth) and bloating (subjective sensation of abdominal fullness) 1
• Perform a digital rectal examination to identify potential pelvic floor disorders, which frequently present with bloating and distention 1

Identifying Abdominophrenic Dyssynergia (APD)

• Assess for APD, which is characterized by paradoxical diaphragmatic contraction (downward movement) and relaxation of anterior abdominal wall muscles 1
• APD can be identified through:
  • Observation of abdominothoracic wall motion during episodes of distention 2
  • Inductance plethysmography using adaptable belts to record abdominal and thoracic wall motion 2
  • Electromyography (EMG) of the abdominothoracic wall during basal conditions and during episodes of distention 3

Advanced Diagnostic Testing

• Reserve abdominal imaging and upper endoscopy for patients with alarm features, recent worsening symptoms, or abnormal physical examination findings 1
• Consider anorectal physiology testing combined with balloon expulsion in patients with suspected pelvic floor disorders 1
• Avoid routine gastric emptying studies for isolated bloating and distention; only consider if nausea and vomiting are present 1
• Rule out carbohydrate enzyme deficiencies with dietary restriction and/or breath testing 1

Measurement Techniques

Objective Measurement

• Computed tomography (CT) can objectively measure changes in abdominal volume and diaphragmatic position during distention episodes 4
• Inductance plethysmography provides real-time measurement of abdominal and thoracic wall motion 2
• EMG recordings of intercostal and abdominal wall muscles can quantify the muscular activity associated with distention 3

Clinical Assessment

• Measure abdominal girth with a measuring tape at standardized anatomical landmarks during both basal state and distention episodes 5
• Use graphic rating scales for patients to record subjective sensation of abdominal distention over consecutive days 5
• Document the temporal relationship between meals and distention episodes, as APD often occurs during or immediately after meals 1

Common Pitfalls and Caveats

• Avoid attributing all abdominal distention to gas accumulation, as studies show that even small increases in intraluminal gas (approximately 10%) can trigger significant distention in patients with APD 1
• Do not routinely order probiotics for abdominal bloating and distention, as evidence does not support their efficacy 1
• Recognize that patients with severe intestinal dysmotility (e.g., intestinal pseudo-obstruction) may present with similar symptoms but without the APD pattern 1
• Be aware that bloating and abdominal fullness can be presenting symptoms in women with ovarian cancer, particularly those 50 years or older 1

Treatment Considerations Based on Assessment

• For confirmed APD, consider diaphragmatic breathing techniques which reduce vagal tone and sympathetic activity 1
• EMG-guided, respiratory-targeted biofeedback therapy has been shown to effectively reduce abdominal distention by correcting the abdominothoracic muscle activity 3, 5, 2
• For distention associated with constipation, consider medications used to treat constipation 1
• Central neuromodulators (e.g., antidepressants) may be effective for treating distention by reducing visceral hypersensitivity 1
• When dietary modifications are needed, involve a gastroenterology dietitian to monitor treatment 1