Table Causes of Intestinal Obstruction Location Cause Colon Tumors (usually in left colon), diverticulitis (usually in sigmoid), volvulus of sigmoid or cecum, fecal impaction, Hirschsprung disease, Crohn disease Duodenum Adults Cancer of the duodenum or cancer of the head of pancreas, ulcer disease Neonates Atresia, volvulus, bands, annular pancreas Jejunum and ileum Adults Hernias, adhesions (common), tumors, Meckel diverticulum, Crohn disease (uncommon), Ascaris infestation, midgut volvulus, intussusception by tumor (rare), foreign body, gallstones (rare) Neonates Meconium ileus, volvulus of a malrotated gut, atresia, intussusception Pathophysiology of Intestinal Obstruction In simple mechanical obstruction, blockage occurs without vascular compromise.