Ileus

Ileus or gastrointestinal atony is a disruption of the normal propulsive gastrointestinal motor activity due to non-mechanical causes. In contrast, motility disorders that result from structural abnormalities are termed mechanical bowel obstruction. Some mechanical obstructions are misnomers, such as gallstone ileus and meconium ileus, and are not true examples of ileus by the classic definition.

Postoperative Ileus
It is a temporary paralysis of a portion of the intestines typically after an 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 from auscultation of the area where this portion lies.

Paralytic Ileus
Paralysis of the intestine. To be termed "paralytic ileus," the intestinal paralysis need not be complete, but it must be sufficient to prohibit the passage of food through the intestine and lead to intestinal blockage.

Paralytic ileus is a common side effect of some types of surgery. It can also result from certain drugs and from various injuries and illnesses. Paralytic ileus causes constipation and bloating. On listening to the abdomen with a stethoscope, no bowel sounds are heard because the bowel is inactive.

Acute colonic pseudoobstruction
Also known as Ogilvie's syndrome.

Inflammation
Ileus may increase adhesion formation, because intestinal segments have more prolonged contact, allowing fibrous adhesions to form, and intestinal distention causes serosal injury and ischemia. Intestinal distention has been shown to cause adhesions in foals. Some respondents also mentioned the importance of walking horses postoperatively to stimulate motility. Repeat celiotomy to decompress chronically distended small intestine and remove fibrinous adhesions is also a useful method of treating ileus and reducting adhesions, and it has been associated with a good outcome

Symptoms
Symptoms of ileus include, but are not limited to:
 * moderate, diffuse abdominal discomfort
 * constipation
 * abdominal distension
 * nausea/vomiting, especially after meals
 * lack of bowel movement and/or flatulence
 * excessive belching

Risk Factors

 * gastrointestinal surgery or other GI procedures
 * electrolyte imbalance
 * diabetic ketoacidosis (DKA), and other causes of metabolic acidosis
 * hypothyroidism
 * medications (e.g. opiates)
 * severe illness (Inflammation with peritonitis)
 * spinal cord injury (SCI), those with injury above thoracic vertebrae 5 (T5) will have hypomotility problems within the bowel

Treatment
Nil per os (NPO or "Nothing by Mouth") is mandatory in all cases. Nasogastric suction and parenteral feeds may be required until passage is restored.

There are several options 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 (Ogilvie's syndrome), neostigmine.

If possible the underlying cause is corrected (e.g. replace electrolytes).