Intestinal obstruction

Alternative names:

bowel obstruction; ileus; intestinal volvulus; paralytic ileus

Definition:

An intestinal obstruction is a partial or complete blockage that results in the failure of the intestinal contents to pass through the bowel. A volvulus is a twisting of the bowel on itself. It is one cause of intestinal obstruction.

Causes, incidence, and risk factors:

Obstruction of the bowel can occur either from ileus (a non-mechanical obstruction) or mechanical causes. Paralytic ileus is a one of the major causes of obstruction in infants and children. The causes of paralytic ileus may include:

• intraperitoneal infection
• mesenteric ischemia (decreased blood supply to the support structures in the abdomen)
• injury to the abdominal blood supply
• after intra-abdominal surgery
• kidney or thoracic disease
• metabolic disturbances (such as decreased potassium levels)

Paralytic ileus can cause gastroenteritis, electrolyte imbalances, and pneumonia in infants; and peritonitis, ruptured appendix, and uremia in older children. Paralytic ileus is marked by abdominal distention, absent bowel sounds (no noise heard when listening to abdomen) and very little pain (as compared to mechanical obstruction). The incidence of paralytic ileus is high in comparison to mechanical obstruction but paralytic ileus is not as significant as 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:

• hernias
• postoperative adhesions or scar tissue
• impacted feces (stool), gallstones
• tumor
• granulomatous processes (abnormal tissue growth)
• intussusception (a condition where the intestine "telescopes" in on itself), volvulus (a twisted intestine)
• foreign bodies

If the obstruction blocks the blood supply to the intestine, the tissue may die, causing infection and gangrene. Risk factors are intestinal malignancy, Crohn's disease, hernia, and previous abdominal surgery. The incidence is 2 out of 2,000 people.