Dogs often eat objects other than food. Balls, corn cobs, socks, coins, strings, etc., are all examples of foreign bodies. Many objects are too large to leave the stomach. Smaller objects, however, such as marbles, paper clips, and strings can pass through the stomach, but may cause a blockage of the small intestine.
What are the symptoms?
Vomiting and a poor appetite are generally the initial signs of a foreign body in the small intestine. The dog will usually have a tense abdomen with few or no bowel movements. Commonly, the temperature is elevated, especially if the intestine has been punctured.
What are the risks?
Strings (yarn, fishing line, etc.) present the greatest danger. Because of their length, they involve a longer section of the bowel. Movement of the small intestine causes 'bunching up' on the string much like an accordion. With continued waves of movement across this area, the string becomes tighter and cuts through the wall of the intestine, often in several places. This results in peritonitis (inflammation of the thin lining of the abdominal cavity) when the intestinal contents leak into the abdomen. These 'linear string foreign bodies' can also cause an intussusception. Most larger intestinal foreign bodies simply get stuck in the intestine, where they cause a blockage that prevents food from moving through the tract. All suspected incidences of an intestinal foreign body are emergencies and should be monitored closely.
What is the management?
Radiographs, occasionally with barium, are used to confirm the diagnosis of intestinal foreign bodies. Surgery is generally required to remove the object or material. Often, the damaged section of the intestine must be removed and the unaffected ends reattached. In some cases, lubricating agents such as petroleum jelly can be used to help the foreign body slide on into the colon, which is larger than the small intestine. From there, objects can pass on. Most dogs fully recover once surgical correction is accomplished, if the foreign body has not penetrated through the intestine. If penetration has occurred, the prognosis is much more guarded.