From the Guidelines
Abdominal distention is primarily caused by excess gas, fluid accumulation, and mechanical obstruction, with the most recent and highest quality evidence suggesting that bowel obstruction, ascites, and inflammatory conditions are significant contributors to this condition. The causes of abdominal distention can be multifactorial, including:
- Excess gas in the digestive tract
- Constipation
- Swallowed air
- Food intolerances
- Intestinal disorders like irritable bowel syndrome (IBS)
- Fluid accumulation in the abdomen (ascites) resulting from liver disease, heart failure, or certain cancers
- Hormonal fluctuations during menstruation
- Small intestinal bacterial overgrowth (SIBO)
- Certain medications such as opioids, anticholinergics, and some antidepressants
- Inflammatory conditions like Crohn's disease or ulcerative colitis
- Partial bowel obstruction from adhesions, hernias, or tumors
According to the most recent study 1, mesenteric vein thrombosis can also lead to bowel distention and ischemia. The management of abdominal distention depends on identifying the underlying cause, which may involve dietary modifications, probiotics, medications targeting specific conditions, or in severe cases, medical procedures to remove excess fluid or relieve obstructions.
Key factors to consider in the management of abdominal distention include:
- Grading of ascites, with mild, moderate, and large ascites requiring different management approaches 2
- Identification of bowel obstruction, which can be caused by adhesions, hernias, or tumors, and may require surgical intervention 3, 4
- Recognition of inflammatory conditions, such as Crohn's disease or ulcerative colitis, which may require specific medical therapy
- Consideration of less common causes of bowel obstruction, such as carcinomatosis, endometriosis, and intussusception 5
Overall, a comprehensive approach to diagnosing and managing abdominal distention is essential to improve patient outcomes and reduce morbidity and mortality.
From the Research
Causes of Abdominal Distention
The causes of abdominal distention are multifaceted and can be attributed to various factors. Some of the possible causes include:
- Food intolerances 6
- Previous infection that perturbed the intestinal microbiota 6
- Disordered visceral sensation 6
- Delayed intestinal transit 6
- Abnormal viscero-somatic reflux 6
- Visceral hypersensitivity 7, 8
- Hyposensitivity and delayed transit 7
- Impaired handling of gas in irritable bowel syndrome 7
- Abnormal relaxation of the anterior abdominal musculature in irritable bowel syndrome patients 7
- Poorly absorbed fermentable carbohydrates 8
- Microbiome alterations 8
- Intestinal strictures, which can be a complication in inflammatory bowel disease (IBD) 9
Pathophysiology and Overlapping Mechanisms
The pathophysiology of abdominal distention is not completely understood, but it is believed to involve different, but overlapping, mechanisms 7, 8. These mechanisms may include:
- Behavioral induced abnormal abdominal wall-phrenic reflexes 8
- The effect of poorly absorbed fermentable carbohydrates 8
- Microbiome alterations 8
- Visceral hypersensitivity and hyposensitivity 7
Relationship to Other Functional Gastrointestinal Disorders
Abdominal distention often coincides with other functional gastrointestinal disorders, such as: