Adynamic ileus is the failure of passage of enteric contents through the small bowel and colon that are not mechanically obstructed. Essentially it represents the paralysis of intestinal motility.
Patients may be asymptomatic or present with symptoms similar to a mechanical bowel obstruction such as nausea/vomiting, distension, and reduced or absent bowel movements. Bowel sounds may also be absent.
Adynamic ileus can be caused by a number of conditions:
- drugs: e.g. opioids
- metabolic: e.g. hyponatremia
- sepsis: especially gram-negative bacteria
- abdominal trauma or surgery (see below)
- myocardial infarction / congestive heart failure
- head injury or neurosurgery
- intra-abdominal inflammation and peritonitis
- retroperitoneal hematoma
The cause of ileus is thought to be complex and multifactorial, involving bowel inflammation 6, inhibitory neural reflexes 7, and neurohormonal peptides 8.
Postoperative ileus vs. paralytic ileus
Some degree of ileus is a normal and expected finding after abdominal surgery, including C-section 9. Conventional recovery times have been reported at 4:
- small intestine: 0-24 hours
- stomach: 24-48 hours
- colon: 48-72 hours
These intervals, however, may be overestimations 5.
Prolonged postoperative ileus (>72 hours) has been termed "paralytic" ileus by some and is concerning for small bowel obstruction, bowel perforation, peritonitis, and intra-abdominal abscess.
Improving postoperative ileus is often determined clinically as much as radiographically, with the resumption of oral intake and flatus.
- generalized, uniform, gaseous distension of the large and small bowel
- involvement of large bowel and lack of a transition point help distinguish it from small bowel obstruction
- when localized, there may be a sentinel loop
History and etymology
"Ileus" ultimately derives from είλειν ("to twist"), which also gave rise to the section of the bowel termed the "ileum". At one time what we now call ileus had been called the "iliack passion" because it was believed that the intestines were twisted 3.
- 1. Brant WE, Helms CA. Fundamentals of diagnostic radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781765188. Read it at Google Books - Find it at Amazon
- 2. Eisenberg RL. Gastrointestinal radiology. Lippincott Williams & Wilkins. (2003) ISBN:0781737060. Read it at Google Books - Find it at Amazon
- 3. Skinner HA. Origin of Medical Terms. Hafner Publishing Co Ltd. ISBN:0028523903. Read it at Google Books - Find it at Amazon
- 4. Miedema BW, Johnson JO. Methods for decreasing postoperative gut dysmotility. Lancet Oncol. 2003;4 (6): 365-72. Pubmed citation
- 5. Böhm B, Milsom JW, Fazio VW. Postoperative intestinal motility following conventional and laparoscopic intestinal surgery. Arch Surg. 1995;130 (4): 415-9. Pubmed citation
- 6. Kalff JC, Schraut WH, Simmons RL et-al. Surgical manipulation of the gut elicits an intestinal muscularis inflammatory response resulting in postsurgical ileus. Ann. Surg. 1998;228 (5): 652-63. Free text at pubmed - Pubmed citation
- 7. Barquist E, Bonaz B, Martinez V et-al. Neuronal pathways involved in abdominal surgery-induced gastric ileus in rats. Am. J. Physiol. 1996;270 (4 Pt 2): R888-94. Pubmed citation
- 8. Cullen JJ, Eagon JC, Kelly KA. Gastrointestinal peptide hormones during postoperative ileus. Effect of octreotide. Dig. Dis. Sci. 1994;39 (6): 1179-84. Pubmed citation
- 9. Kammen BF, Levine MS, Rubesin SE, Laufer I. Adynamic ileus after caesarean section mimicking intestinal obstruction: findings on abdominal radiographs. (2000) The British journal of radiology. 73 (873): 951-5. doi:10.1259/bjr.73.873.11064647 - Pubmed