Intestinal Pseudo-Obstruction and Adynamic Ileus

Definition and Characteristics

The American Gastroenterological Association notes that adynamic ileus is an acute and reversible disorder of intestinal motility that typically resolves within days, while chronic intestinal pseudo-obstruction (CIPO) is a chronic syndrome (>6 months) with persistent failure of intestinal propulsion that frequently requires long-term nutritional support 1, 2
Adynamic ileus is characterized by a temporary condition that generally resolves spontaneously or with conservative treatment in days, affecting patients with reversible causes such as post-abdominal surgery, abdominal trauma, sepsis, and metabolic or endocrine disorders 1, 3
Chronic intestinal pseudo-obstruction is a syndrome that persists for more than 6 months with recurrent or continuous symptoms, often requiring long-term nutritional support, and is associated with structural abnormalities such as myopathy or neuropathy 1, 2

The European Society for Clinical Nutrition and Metabolism states that CIPO can be caused by myopathy, neuropathy, or secondary to systemic diseases such as scleroderma or connective tissue disorders 5, 4
Adynamic ileus can be caused by reversible conditions such as abdominal surgery, trauma, sepsis, metabolic disorders, endocrine disorders, or medication use 3, 4

The American College of Radiology notes that adynamic ileus is characterized by diffuse dilation of intestinal loops with air-fluid levels and no transition point, while CIPO is characterized by chronic dilation of the small intestine, which is a defining feature 1, 3
CIPO may also affect the colon and is associated with slow transit documented by radiological studies 1, 5

The American Neurogastroenterology and Motility Society states that adynamic ileus is characterized by a temporary absence of contractile activity, while CIPO is characterized by persistent propulsive failure and absence of migrating motor complexes (MMC) 1, 6
CIPO may also be associated with abnormal giant contractions 1

The American Gastroenterological Association notes that adynamic ileus typically presents with acute abdominal distension, absence of bowel sounds, nausea, vomiting, and absence of flatus or bowel movements 3
CIPO presents with chronic abdominal pain, recurrent vomiting, persistent abdominal distension, and alternating constipation and diarrhea, and may lead to progressive malnutrition 1, 2, 6

The European Society for Clinical Nutrition and Metabolism recommends that CIPO requires management in a specialized multidisciplinary center, with frequent need for nutritional support, and notes that patients with myopathy have a poorer prognosis than those with neuropathy 1, 5
Adynamic ileus typically resolves within days with conservative treatment, while CIPO has a variable prognosis with a mortality rate of 10% at 2 years in severe cases 1, 3