Obstruction of the bowel may be caused by ileus -- in which the bowel doesn't function correctly but there is no "mechanical" (anatomic) problem -- or by mechanical causes. Paralytic ileus, also called pseudo-obstruction, is one of the major causes of obstruction in infants and children. The causes of paralytic ileus may include the following: - Medications, especially narcotics
- Intraperitoneal infection
- Mesenteric ischemia (decreased blood supply to the support structures in the abdomen)
- Injury to the abdominal blood supply
- Complications of intra-abdominal surgery
- Kidney or thoracic disease
- Metabolic disturbances (such as decreased potassium levels)
Paralytic ileus may lead to complications causing jaundice and electrolyte imbalances. In the newborn, paralytic ileus that is associated with destruction of the bowel wall (necrotizing enterocolitis) is life-threatening and may lead to infection in the infant's blood and lungs. In older children, gastroenteritis may be a cause of paralytic ileus, which is sometimes associated with peritonitis and a ruptured appendix. Paralytic ileus is marked by abdominal distention, absent bowel sounds (no noise heard when listening to abdomen) and relatively little pain (as compared to mechanical obstruction).
Mechanical obstruction occurs when movement of material through the intestines is physically blocked. The mechanical causes of obstruction are numerous and may include the following: - Hernias
- Postoperative adhesions or scar tissue
- Impacted feces (stool)
- Gallstones
- Tumors blocking the intestines
- Granulomatous processes (abnormal tissue growth)
- Intussusception
- Volvulus (twisted intestine)
- Foreign bodies (ingested materials that obstruct the intestines)
If the obstruction blocks the blood supply to the intestine, the tissue may die, causing infection and gangrene. Risk factors for tissue death include intestinal malignancy, Crohn's disease, hernia, and previous abdominal surgery.
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