Gastrointestinal Foreign Bodies

Dogs have been known to swallow bones, toys, sticks, stones, pins, needles, wood splinters, cloth, rubber balls, rawhide, leather, string, peach pits, and other objects. With string, one end often knots up while the other gets caught in food. Tension on the string then causes it to cut through the wall of the bowel. Swallowing pennies will not usually cause an obstruction, but can lead to zinc toxicity as the metal leaches out of the coins. Batteries can also cause toxicity when swallowed.

The esophagus of the dog is larger than the outlet of his stomach. Thus, dogs may swallow objects that are too large to pass out of the stomach. Gastric foreign bodies are therefore associated with chronic gastritis and episodes of gastric outflow obstruction.

If an object makes it into the small intestine, it may pass through the entire GI tract without causing problems. Those that do cause an obstruction usually do so at the ileocecal valve or in the colon and rectum. Foreign bodies in the rectum cause anorectal obstructions. Sharp objects such as pins, splinters, and bone chips can lodge anywhere in the GI tract and obstruct or perforate the bowel, causing intestinal obstruction or peritonitis.

Unless it also causes indigestion, a swallowed foreign body will go unnoticed until it produces symptoms. Many foreign bodies can be seen on X-rays of the abdomen if they are radio-opaque. A contrast study may be needed to identify foreign bodies that are not visible on X-rays.

Treatment: Foreign bodies that produce symptoms should be removed. This usually involves abdominal surgery. Gastric foreign bodies can sometimes be removed through an endoscope.