| Ileus | |
|---|---|
 | |
| Gangrene of the bowel causing gangrenous ileus | |
| Pronunciation | |
| Specialty | Gastroenterology,general surgery |
Ileus is a disruption of the normalpropulsive ability of theintestine. It can be caused by lack ofperistalsis or bymechanical obstruction.[1]The word 'ileus' derives from Ancient Greek εἰλεός (eileós) 'intestinal obstruction'. The term 'subileus' refers to a partial obstruction.[2]
Symptoms of ileus include, but are not limited to:[citation needed]
Decreased propulsive ability may be broadly classified as caused either bybowel obstruction or by intestinalatony or paralysis. However, instances with symptoms and signs of a bowel obstruction occur, but with the absence of a mechanical obstruction, mainly in acute colonicpseudo-obstruction,Ogilvie's syndrome.[3] In 2023 the USFDA reported gastrointestinal ileus as anadverse effect of the medicationsemaglutide, with frequency and causal relationship unknown.[4]
A bowel obstruction is generally a mechanical obstruction of the gastrointestinal tract and can occur anywhere from theLigament of Treitz to theanus. When the obstruction affects only the small intestine, it is generally referred to as a small bowel obstruction to distinguish it from a colonic obstruction, which may or may not affect the small intestine. The distinction helps to narrow the possible causes and treatment.
Common causes of small bowel obstruction include post-operativeadhesions,hernias,intussusception, and intraabdominaltumors. Common causes of colonic obstruction include primarycolon cancer,volvulus and post-operative adhesions. When theileocecal valve is competent, colonic obstruction may manifest as gaseous distention of the colon, but not the small intestine; when the ileocecal valve is incompetent, it does not prevent retrograde passage of air and stool and a colonic obstruction will cause dilation of both large and small bowel.
Bowel obstructions can be partial or complete. They can be differentiated on imaging by the intestinal gas pattern. Partial obstructions will have gas distal to the obstruction, whereas a complete obstruction will not. Sounds of "rushes and tinkles" are associated with partial obstructions[5] and represent brief passages of fluid and gas (respectively) through the partial obstruction. Complete obstructions do not make these sounds.
Paralytic ileus is paralysis of the intestine, whether or not complete, sufficient to prohibit the passage of food through the intestine and lead to intestinal blockage. It causes constipation and bloating. On listening to the abdomen with astethoscope, no bowel sounds are heard because the bowel is inactive.[citation needed] It is a common side effect of some types of surgery, termed postsurgical ileus. It can also result from certain drugs and from various injuries and illnesses, such asacute pancreatitis.
A temporary paralysis of a portion of the intestines occurs typically after abdominal surgery. Since the intestinal content of this portion is unable to move forward, food or drink should be avoided untilperistaltic sound is heard, byauscultation (use of a stethoscope) of the area where this portion lies. Intestinal atony or paralysis may be caused by inhibitory neural reflexes, inflammation or other implication of neurohumoral peptides.[citation needed]
Traditionally,nothing by mouth was considered to be mandatory in all cases, but gentle feeding by enteralfeeding tube may help to restore motility by triggering the gut's normal feedback signals, so this is the recommended management initially.[7] When the patient has severe, persistent signs that motility is completely disrupted,nasogastric suction andparenteral nutrition may be required until passage is restored. In such cases, continuing aggressive enteral feeding causes a risk of perforating the gut.
Several options are available in the case of paralytic ileus. Most treatment is supportive. If caused by medication, the offending agent is discontinued or reduced. Bowel movements may be stimulated by prescribinglactulose,erythromycin or, in severe cases that are thought to have a neurological component (such asOgilvie's syndrome),neostigmine. There is also evidence from a systematic review ofrandomized controlled trials that chewing gum, as a form of 'sham feeding', may stimulate gastrointestinal motility in the post-operative period and reduce the duration of postoperative ileus.[8]
If possible the underlying cause is corrected (e.g. replace electrolytes).
Ileus can occur in other mammals. Ileus is a cause ofcolic in horses due to functional obstruction of the intestines. It is most commonly seen in horses postoperatively, especially following colic surgery.[9] Horses experiencing ileus are at risk for gastric rupture due to rapid reflux build-up, and require intense medical management with frequent nasogastric intubation.[9] Ileus may increaseadhesion formation, because intestinal segments have more prolonged contact and intestinal distention causes serosal injury andischemia. It is usually treated with aggressive fluid support,prokinetics, and anti-inflammatories.[9]
Ileus can also be seen in cats.[10][11]
ICD-10 coding reflects both impaired-peristalsis senses and mechanical-obstruction senses of the term as modified by various adjectives.[1] Some authors have argued for trying to reserve the term for the impaired-peristalsis senses,[12][13] under whichprescription certain older terms such as "gallstone ileus" and "meconium ileus", although now technicallymisnomers, are still accepted as correct owing to their long-established usage.[14]