Volvulus, Intestinal

• A twist about the long axis of the gut.
• Generally in the small intestine.
• Intense congestion
  • Often almost black.
• Mostly in young animals
  • Especially calves and piglets
  • Occasionally sheep and dogs.
  • Occasionally in greater mesentery of horse.

Pathogenesis

• Loop of bowel twists through 180 degrees around mesentery to produce obstruction of lumen.
• Proximal the the obstruction, the bowel becomes rapidly distended.
  • Venous return is first shut off, but the arterial supply remains.
    • Bowel becomes engorged with blood.
  • Produces rapid death.
• Bowel becomes hypoxic.
  

  Torsion of the large colon in the horse (Courtesy of Elspeth Milne)
  • Toxic material and bacteria pass through the anoxic wall of bowel.
• In piglets may see whole of small intestine twisted around root of mesentery.
  • Very little can be done to resolve this** Produces rapid death