Ileus is a disruption of the normal propulsion ability of the intestine. It can be caused by lack of peristalsis or by mechanical obstruction.
Signs and symptoms
Symptoms of ileus include, but are not limited to:
Cause
Decreased propulsive ability may be broadly classified as caused either by bowel obstruction or by intestinal
atony or paralysis. However, instances with symptoms and signs of a bowel obstruction occur, but with the absence of a mechanical obstruction, mainly in acute colonic pseudo-obstruction, Ogilvie's syndrome.
[Ponec RJ, Saunders MD, Kimmey MB (1999). "Neostigmine for the treatment of acute colonic pseudo-obstruction". N. Engl. J. Med. 341 (3): 137–41. doi:10.1056/NEJM199907153410301. PMID 10403850.] In 2023 the US
FDA reported gastrointestinal ileus as an
Side effect of the medication
semaglutide, with frequency and causal relationship unknown.
Bowel obstruction
A bowel obstruction is generally a mechanical obstruction of the gastrointestinal tract and can occur anywhere from the Ligament of Treitz to the
anus. 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-operative adhesions, hernias, intussusception, and intraabdominal Neoplasm. Common causes of colonic obstruction include primary colon cancer, volvulus and post-operative adhesions. When the ileocecal 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
Intestinal paralysis
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 a
stethoscope, no bowel sounds are heard because the bowel is inactive. 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 as acute 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 until peristaltic sound is heard, by auscultation (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.
Risk factors
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gastrointestinal surgery or other GI procedures
-
electrolyte imbalance (Namely hypokalemia and hypercalcemia)
-
diabetic ketoacidosis (DKA),
-
hypothyroidism
-
diabetes
-
medications (e.g. opioids or )
-
severe illness (inflammation with peritonitis)
-
spinal cord injury, those with injury above thoracic vertebra 5 (T5) will have hypomotility problems within the bowel
-
acute intermittent porphyria
Treatment
Traditionally, nothing by mouth was considered to be mandatory in all cases, but gentle feeding by enteral
feeding tube may help to restore motility by triggering the gut's normal feedback signals, so this is the recommended management initially.
When the patient has severe, persistent signs that motility is completely disrupted, nasogastric suction and parenteral 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 prescribing lactulose, erythromycin or, in severe cases that are thought to have a neurological component (such as Ogilvie's syndrome), neostigmine. There is also evidence from a systematic review of randomized 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.
If possible the underlying cause is corrected (e.g. replace electrolytes).
Other animals
Ileus can occur in other mammals. Ileus is a cause of colic in horses due to functional obstruction of the intestines. It is most commonly seen in horses postoperatively, especially following colic surgery.
Horses experiencing ileus are at risk for gastric rupture due to rapid reflux build-up, and require intense medical management with frequent nasogastric intubation.
Ileus may increase adhesion formation, because intestinal segments have more prolonged contact and intestinal distention causes serosal injury and
ischemia. It is usually treated with aggressive fluid support,
, and anti-inflammatories.
Ileus can also be seen in cats.
Terminology
ICD-10 coding reflects both impaired-peristalsis senses and mechanical-obstruction senses of the term as modified by various adjectives.
Some authors have argued for trying to reserve the term for the impaired-peristalsis senses,
under which prescription certain older terms such as "
gallstone ileus" and "
meconium ileus", although now technically
, are still accepted as correct owing to their long-established usage.
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