Ileus

Overview
Ileus is a disruption of the normal propulsive gastrointestinal motor activity from non-mechanical mechanisms. 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.

Mechanical Obstruction

 * Adenomatous polyps
 * Adhesions
 * Adhesive bands
 * Annular pancreas
 * Ascariades
 * Atresia
 * Biliary calculus
 * Bowel duplication
 * Carcinomatosis
 * Colon Cancer
 * Congenital megacolon
 * Crohn's Disease
 * Cysts
 * Diverticular stricture
 * Diverticulitis
 * Endometriosis
 * Foreign body
 * Gallstone ileus
 * Hematoma of the bowel wall
 * Hernia
 * Hirschprung's disease
 * Iatrogenic
 * Imperforate anus
 * Incarcerated hernia
 * Inflammatory
 * Intrabdominal abscess
 * Intrabdominal hematoma
 * Invagination, intussisception
 * Ischemia
 * Malrotation
 * Meckel's Diverticulum
 * Megacolon
 * Multiple polyposis syndromes
 * Neoplasm
 * Ovarian Cancer
 * Pneumatosis intestinalis
 * Postoperative
 * Pregnancy
 * Radiation induced stenosis
 * Sarcoma
 * Scleroderma
 * Surgical anastomosis
 * Therapy with dietary fiber
 * Trauma
 * Tuberculosis
 * Ulcerative colitis
 * Volvulus

Non-Mechanical Obstruction

 * Acid-base imbalance
 * Acute pancreatitis
 * Anticholinergics
 * Antihistamines
 * Apoplexy
 * Brain tumor
 * Cancer
 * Catecholamines
 * Cholecystolithiasis
 * Connective tissue disease
 * Diabetic coma
 * Empyema
 * Hyperparathyroidism
 * Hypokalemia
 * Lead poisoning
 * Lymphoma
 * Mechanical ventilation
 * Mesenteric infarction
 * Morphine
 * Narcotics
 * Osteomyelitis of the spine
 * Ovarian torsion
 * Pancreatitis
 * Penetrating wounds
 * Perinephric abscess
 * Peritoneal carcinomatosis
 * Peritonitis
 * Pneumonia
 * Porphyria
 * Postoperative
 * Psoas abscess
 * Pyelonephritis
 * Renal colic
 * Retroperitoneal hematoma
 * Spinal cord inflammation
 * Spinal cord injury
 * Spinal cord trauma
 * Systemic infection
 * Testicular torsion
 * Ulcer perforation
 * Uremia
 * Urosepsis
 * Vitamin deficiency

Pseudo-Obstruction

 * Aerophagia
 * Functional bowel disease

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.

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. In a recent survey of ACVS diplomates on drugs to prevent ileus and therefore prevent adhesions (unpublished data). The drug used in this survey was lidocaine, erythromycin, and cisapride. 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

Risk Factors

 * gastrointestinal surgery or other GI procedures
 * electrolyte imbalance
 * hypothyroidism
 * medications (e.g. opiates)
 * severe illness

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).