Ileus: Causes, Symptoms and Treatment
Ileus refers to a partial or complete non-mechanical blockage of the small and/or large intestine. Therefore ileus is a temporary arrest of intestinal peristalsis.
Types of intestinal obstruction
There are two types of intestinal obstructions:
- Mechanical intestinal obstruction and
- Non-mechanical intestinal obstruction.
Mechanical obstructions occur because the bowel is physically blocked and its contents can not pass the point of the obstruction.
This happens when the bowel twists on itself (volvulus) or as the result of hernias, impacted feces, abnormal tissue growth, or the presence of foreign bodies in the intestines.
Non-mechanical obstruction, called ileus or paralytic ileus, occurs because peristalsis stops.
Peristalsis is the rhythmic contraction that moves material through the bowel.
Ileus is most often associated with an infection of the peritoneum (the membrane lining the abdomen).
It is one of the major causes of bowel obstruction in infants and children.
Etiology of Ileus
- In addition to postoperative causes, it also results from:
- Intraperitoneal or retroperitoneal inflammation (eg, appendicitis, diverticulitis, perforated duodenal ulcer),
- Retroperitoneal or intra-abdominal hematomas (eg, ruptured abdominal aortic aneurysm, lumbar compression fracture),
- Metabolic disturbances (eg, hypokalemia),
- Drugs (eg, opioids, anticholinergics, sometimes Calcium channel blockers).
- Ileus sometimes occurs in association with renal or thoracic disease (eg, lower rib fractures, lower lobe pneumonia, Myocardial infarction).
Gastric and colonic motility disturbances after abdominal surgery are common.
The small bowel is typically least affected, with motility and absorption returning to normal within hours after surgery.
Stomach emptying is usually impaired for about 24 h or more.
The colon is often most affected and may remain inactive for 48 to 72 h or more.
Signs and symptoms of ileus
- Abdominal distention,
- Vomiting, and
- Vague discomfort.
- Pain rarely has the classic colicky pattern present in mechanical obstruction.
- There may be obstipation or passage of slight amounts of watery stool.
- Auscultation reveals a silent abdomen or minimal peristalsis.
- The abdomen is not tender unless the underlying cause is inflammatory.
Diagnosis and Investigation
The diagnosis is usually reached from clinical evaluation and sometimes x-rays.
The most essential task is to distinguish ileus from intestinal obstruction.
In both conditions, x-rays show gaseous distention of isolated segments of the intestine.
In postoperative ileus, however, gas may accumulate more in the colon than in the small bowel.
Postoperative accumulation of gas in the small bowel often implies the development of a complication (eg, obstruction, peritonitis).
In other types of ileus, x-ray findings are similar to obstruction; differentiation can be difficult unless clinical features clearly favor one or the other.
Water-soluble contrast studies may help differentiate.
Continuous nasogastric suction,
Nil per oral status,
Intravenous fluids and electrolytes, a minimal amount of sedatives, and avoidance of opioids and anticholinergic drugs.
Maintaining an adequate serum potassium level (> 4 mEq/L [> 4 mmol/L]) is especially important.
Ileus persisting for more than one week probably has a mechanical obstructive cause, and laparotomy should be considered.
Sometimes colonic ileus can be relieved by colonoscopic decompression; rarely, cecostomy is required.
Colonoscopic decompression is helpful in treating pseudo-obstruction (Ogilvie's syndrome), which consists of apparent obstruction at the splenic flexure, although no cause can be found by contrast enema or colonoscopy for the failure of gas and feces to pass this point.
Some clinicians use intravenous neostigmine (requires cardiac monitoring) to treat Ogilvie's syndrome.
It occurs most commonly after abdominal surgery, particularly when the intestines have been manipulated.
Symptoms are nausea, vomiting, and vague abdominal discomfort.
Treatment is supportive, with nasogastric suction and IV fluids.