Gastrointestinal foreign bodies in dogs and cats
Dogs and cats may ingest an object that can pass down the oesophagus but is unable to pass out of the stomach or along the intestine (guts). This is known as a gastrointestinal foreign body. Symptoms of this usually include vomiting, loss of appetite and depression. Urgent medical supportive care along with surgical removal is usually required to prevent possible blockage or perforation of the digestive tract, which might lead to overwhelming infection (peritonitis), shock and death.
The clinical signs of a pet having swallowed a foreign body are very variable and can range from no signs at all to signs of shock and depression due to obstruction of the intestine or stomach, or even intestinal perforation and subsequent peritonitis.
Symptoms that may be shown by a dog or cat following ingestion of a foreign object include nausea, acute and repeated vomiting of food or bile, loss of appetite, depression, and lethargy. Vomiting is the most common clinical sign. If the foreign object cannot pass into the intestine, it can remain in the stomach for a long period causing intermittent chronic vomiting.
Many foreign bodies enter the small intestine and the symptoms may resemble those of classic gastroenteritis such as vomiting or possibly diarrhoea. They cause irritation and partial obstruction of the digestive tract.
If the object becomes lodged and completely blocks the intestine, an urgent situation develops as the surrounding intestine deteriorates, and the animal’s condition may worsen rapidly. This can happen within hours of ingesting a foreign object or more commonly will happen later on and worsen over time. Vomiting can become persistent and if the pet is clearly unwell, with a very painful abdomen it is possible that the intestine has perforated. If this occurs, the pet will rapidly deteriorate, and can collapse and die if urgent veterinary attention is not given. Even if veterinary attention is given at this late stage, the pet is still at great risk; so it is always imperative that veterinary advice is sought as soon as possible.
The diagnosis of a gastrointestinal foreign body is made by the veterinary surgeon based on the symptoms, clinical signs and the history of possibly having ingested a foreign body. Sometimes the owner may have witnessed this, thus making the diagnosis easier.
Depending on the size and location of the foreign body and how slim the pet is, the object may be palpated or ‘felt’ though the abdominal wall. A string-like foreign body is far more difficult to detect on palpation. Sometimes it can be seen if a length is lodged under the pet’s tongue.
It will usually be necessary to take x-rays of the pet’s abdomen to confirm the presence of a foreign body in the stomach or the intestine. However, some foreign bodies are not visible on x-ray and other tests (ultrasound or special contrast x-rays) may be necessary.
Additional tests (e.g. blood tests) might be performed depending on the animal’s clinical condition.
Although some foreign bodies are small enough to pass along the intestine with no problem, many will need removal.
Surgical or other procedures will be used to remove foreign bodies from the stomach.
The amount of supportive care given will depend on the condition of the animal. It is often vital to stabilise an animal first before surgery or gastroscopy to remove the foreign body. This will usually involve fluids given intravenously (“drip”). Other appropriate medications such antiemetics (to stop vomiting), gastro-protectants (to protect the stomach and intestinal lining) and antibiotics may be given before and/or after any surgery.
It is important to discourage dogs from scavenging to reduce the risk of ingesting inappropriate items. Ensure that toys are appropriate and not easily broken by chewing. Such items are likely to cause an obstruction if swallowed. Also be careful not to leave string or thread lying around, especially with a needle attached.
If you think your cat or dog may have swallowed a foreign body, your veterinary surgeon should be contacted quickly for advice and appropriate care.
The gastrointestinal (digestive) tract of the cat and dog is a one-way system. Only the stomach has the ability to over-ride this; allowing the animal to vomit stomach contents back up. Once it reaches the small intestine, everything eaten is committed to be moved along the intestinal tract and digested if possible.
Dogs are affected more commonly than cats because they scavenge more. Puppies are also prone to swallowing foreign objects, as they play or chew on toys and other items they encounter.
Many types of gastrointestinal foreign body have been reported. Common foreign bodies include plastic balls, squeaky toys, bones, corks, bottle caps, discarded corn cobs, stones, and large fruit stones. Irregular objects such as stones or sharp objects (needles, fishhooks, etc.) cause the most damage to the lining of the stomach or intestine.
Some foreign bodies are string-like (or linear). This may be the string wrapped around a joint of meat, or Christmas wrapping ribbon. Cats may also play with a reel of cotton and if there is a needle attached, this may be swallowed and have serious consequences. Some linear foreign bodies may also become wrapped around the tongue; this is most commonly seen in cats. These linear foreign bodies may cause severe damage to the stomach or intestines and perforation and peritonitis can subsequently occur so they must be dealt with urgently.
If the dog does not vomit a foreign body back up, it may remain lodged in the stomach if it is too large to pass through the valve to the small intestine. Most objects will however pass through this valve, and can make an irregular passage along the intestine if they are small enough. Many succeed in reaching the slightly narrower valve at the junction of the small and large intestine. If they can pass through this, there is unlikely to be any problem unless it has damaged the intestines on route and the foreign body should pass out in the faeces.