Visible abdominal distension in functional gut disorders: Objective evaluation.

Area of Science:

• Gastroenterology
• Functional Gut Disorders
• Abdominal Imaging and Electrophysiology

Background:

• Visible abdominal distension is a common symptom in functional gut disorders.
• Potential causes include distorted perception, intestinal gas, and abdominophrenic dyssynergia.

Purpose of the Study:

• To objectively investigate the underlying mechanisms of visible abdominal distension in patients with functional gut disorders.
• To differentiate between gas accumulation and abdominophrenic dyssynergia as causes of distension.

Main Methods:

• Analysis of 139 patients with functional gut disorders and visible abdominal distension.
• Objective measurements included tape measure, static abdominal CT scans, and dynamic EMG recordings of abdominal walls and diaphragm.
• Patients were evaluated under basal conditions and during self-reported distension episodes.

Main Results:

• Objective evidence of distension was confirmed in 138/139 patients by tape measure, 96/104 by CT, and 73/76 by EMG (reduced abdominal wall activity).
• Intestinal gas volume did not correlate with distension in most patients (99/104), with only 5 showing increased gas.
• Abdominophrenic dyssynergia was consistently observed, with diaphragmatic contraction (EMG: 34/35, CT: 82/103) and abdominal wall relaxation.

Conclusions:

• Subjective claims of visible abdominal distension are objectively verifiable.
• Increased intestinal gas is not the primary driver of visible abdominal distension.
• Abdominophrenic dyssynergia is the consistent finding, with dynamic EMG being more sensitive than static CT for diagnosis.