Intestinal blockage and foreign bodies in dogs: symptoms and treatment

Overview

An obstruction can be partial or complete. A swallowed object may lodge in the stomach or different parts of the intestine. A large round object can completely block the bowel. A narrow or thread-like foreign body more often causes partial obstruction.

A small, smooth object can sometimes pass through without causing obstruction. Fluid and gas accumulate before the blockage and stretch the bowel. The outlook is usually good when foreign-body obstruction is recognised and treated promptly.

One surgical follow-up of 72 patients classified obstruction as chronic when at least seven days had passed between symptom onset or witnessed ingestion and presentation. The chronic obstruction group included 52 dogs and 20 cats.

Complete obstruction can cause rapid deterioration. Partial obstruction may cause more slowly developing digestive symptoms.

Causes

Digestion does not break down plastic fragments or stones, so they can remain in the intestine. A bone can lodge if it breaks down too slowly during digestion. One end of a long string can become anchored under the tongue or in the stomach. As the intestine tries to move the free end onwards, it can bunch up around the string.

Obstruction can also occur when one bowel segment slides inside an adjacent segment. This intussusception can be associated with parvovirus infection, for example. A tumour growing in the bowel wall can narrow the lumen. The bowel can also twist or become trapped in a hernia opening.

Several swallowed objects can lodge at different intestinal sites. Magnets can attract one another through bowel walls and compress the tissue between them. A leaking battery can release corrosive material into the digestive tract.

Risk factors

Foreign-body obstruction is more common in young large-breed dogs than in elderly dogs. Risk may increase with repeatedly eating non-food objects. A disease markedly increasing appetite can predispose to swallowing a foreign body. Appetite-stimulating medication can also increase risk.

The size of object posing a danger depends partly on the dog's size. A damaged toy can shed pieces small enough to swallow. Socks and underwear taken from laundry baskets are other possible foreign bodies.

In a Thai group of 150 canine patients, 20.00% of objects retained in the stomach were fabric. Metal accounted for 18.00% in the same group. Gastric foreign bodies can range from fabric and plastic to plant material.

Typical symptoms

Symptoms vary with obstruction location and duration. Obstruction near the end of the small intestine may cause less vomiting.

• Repeated vomiting.
• Reduced or absent appetite.
• Abdominal tenderness when touched.
• Dullness and less interest in the surroundings.
• Diarrhoea-like faeces or visible blood.
• Reduced or absent defaecation.

Thread visible in the mouth may be anchored under the tongue. The end of a linear foreign body can sometimes also protrude from the anus.

A dog can lose weight during chronic obstruction. In dogs operated on for chronic foreign-body obstruction, median time from symptoms or known ingestion to presentation was 10.5 days.

Complications and consequences

Repeated vomiting can rapidly dehydrate a dog. Vomiting and fluid trapped in the intestine can disturb fluid and electrolyte balance. Pressure and impaired circulation can damage bowel at the blockage. Trapped bowel can develop tissue death in its wall.

A taut string can cut through the bowel wall. Perforation can release contents into the abdomen and cause peritonitis. Severe infection can lead to sepsis, a dangerous systemic response to infection. Inhaling vomit can cause pneumonia.

The surgical closure can fail if the bowel wall does not heal normally. Bowel suture breakdown most commonly becomes apparent three to five days after surgery. Removing more than 75% of the intestine can impair nutrient absorption through short bowel syndrome. Of 72 dogs and cats operated on for chronic obstruction, 68, or 94%, survived to follow-up.

Major postoperative complications occurred in 11, or 15%, of the dogs and cats treated for chronic obstruction. Breakdown of the surgical closure may require another operation.

Diagnosis at the vet

History and general examination

The vet asks whether ingestion was witnessed and when symptoms began. Feeling the abdomen can sometimes reveal a painful area or intestinal mass. Examining the mouth may reveal string caught under the tongue. Blood tests can assess dehydration and electrolyte changes, for example.

Inflammation associated with perforation can markedly increase or decrease white blood cell numbers. Blood chloride may decrease regardless of obstruction location.

X-rays and ultrasound

Metal, stone or bone may be directly visible on an abdominal X-ray. Fabric and plastic can be difficult to see despite resulting intestinal changes. With complete obstruction, some small-bowel loops may enlarge as fluid or gas accumulates. Bunching caused by a linear foreign body may be visible on X-rays.

Ultrasound can locate a foreign body and show enlarged, fluid-filled bowel segments. Abundant intestinal gas can hinder examination. Intussusception may appear as concentric rings in an ultrasound cross-section. Free abdominal gas or fluid may raise suspicion of perforation.

Sampling abdominal fluid can assess possible bacterial peritonitis. Contrast imaging can help locate an object not visible on ordinary X-rays. If perforation is suspected, water-soluble iodine contrast may be chosen. Some unclear cases require CT.

In one case from northern Europe, several enlarged, gas-filled bowel segments strengthened suspicion of obstruction. The same dog's previous tendency to eat clothing supported suspicion of a foreign body.

Treatment

Monitoring, inducing vomiting and endoscopy

For a small, smooth object in a stable dog, the vet may consider monitoring its progress. An X-ray-visible object can be followed with repeat images. If an object under close monitoring has not passed within 36–48 hours, surgery may be needed. Deterioration during monitoring may require immediate surgery.

If a suitable object is still in the stomach, endoscopic removal may be considered. An endoscope usually reaches only the stomach and start of the small intestine. A long string extending into the small intestine often needs surgery. In some circumstances, the vet may induce vomiting within one to two hours of ingestion if the object is suitable for removal this way. For sharp or corrosive objects, another removal method is chosen.

Surgery and recovery

Before anaesthesia, the vet aims to correct fluid and electrolyte disturbances. An object lodged in the small intestine can be removed through an incision in the bowel. The entire digestive tract is checked during surgery because several objects may be present. Irreversibly damaged bowel is removed and healthy ends joined together.

Intravenous fluids may continue after surgery. Vital functions may be monitored in hospital for the first 12–24 hours after abdominal surgery. A tube passed through the nose can remove stomach fluid and gas when needed. At the vet's discretion, feeding may begin 12–24 hours after recovery from anaesthesia if the dog is not vomiting.

Enteral nutrition supports bowel healing once the dog can eat again. Electrolytes may be checked during recovery.

Obstruction-associated peritonitis may be treated with antibiotics and drainage of accumulating abdominal fluid. Dogs and cats discharged after chronic obstruction surgery stayed in hospital for one to seven postoperative days. Median stay was two days.

Discharge may be possible once the dog eats independently and can take oral medication.

Prevention

Choose toys that do not shed small, swallowable parts. Supervise chewing games to notice loose pieces early. Keep socks and other small clothes out of reach.

Keep strings and threads out of dog play. Teaching a release cue helps remove an object from the mouth before swallowing. A basket muzzle allowing room to pant may help on walks with a dog that repeatedly swallows objects.

Eating large amounts of bone can cause obstruction. Prevent access to sharp bone fragments because they can perforate the bowel wall.

Important for dog owners

Tell the vet the object's size and when it may have been swallowed. Leave string protruding from the mouth or anus for the vet to remove, as pulling can tear the intestine. The vet decides whether to induce vomiting. Salt can cause life-threatening poisoning.

Follow discharge feeding instructions. Restrict jumping as directed after surgery, as vigorous movement strains the wound. Contact the vet if wound edges open or discharge develops.

New vomiting or persistent lack of appetite after surgery warrants contact with the treating vet. Monitor posture and movement during recovery too, as changes can indicate pain.

Keep outings on a lead during exercise restriction, as directed at discharge.

Frequently asked questions

Can a dog pass faeces with an intestinal blockage?

Symptoms depend on location and whether obstruction is partial or complete. Some blockages cause diarrhoea or bloody faeces. Less frequent defaecation can also indicate a foreign body when other symptoms are present.

Is a foreign body always visible on X-rays?

Metal and stones are often clearly visible on abdominal X-rays. Fabric may be invisible, but the blockage can appear as bowel enlargement. Ultrasound can look for the object and fluid accumulation.

Will a swallowed object pass by itself?

A small, smooth object may pass without lodging. The vet can monitor an X-ray-visible object's progress if the dog remains stable. Surgery may be needed if it stops moving or the dog deteriorates.

What should I do if string hangs from my dog's mouth?

Leave string protruding from the mouth or anus in place and contact a vet immediately. One end may be anchored under the tongue or in the stomach. Pulling it taut can tear the bowel wall if it has already reached the small intestine.

When can a dog eat after surgery?

At the vet's discretion, food may be offered 12–24 hours after recovery from anaesthesia if the dog is not vomiting. Enteral nutrition can promote healing. At home, follow the dog's individual discharge feeding instructions.