Gastric Foreign Objects

Signalment

• Dogs affected more often than cats due to their less selective eating habits.
• Puppies are prone.

Description

Ingested objects that are able to pass through the oesophagus may subsequently become a gastric or intestinal foreign object. If small enough, the object may pass through the pylorus and the entire gastrointestinal tract. Others may become intestinal or rectal foreign bodies. Objects that remain in the stomach may be subsequently expelled by vomiting, otherwise they may continue to cause gastric outflow obstruction, gastric distension and irritation.

Diagnosis

History

Reports of the owner witnessing the animal ingesting an object is obviously very helpful in obtaining a diagnosis. However, there is not a history of this in most cases.

Clinical Signs

Some animals may be asymptomatic, otherwise the following signs may present:

• vomiting - due to gastric outflow obstruction, gastric distension and/or irritation.
• inappetence
• anorexia
• dehydration - may occur as a result of prolonged vomiting.
• hypovolaemic shock - uncommon unless the stomach has been perforated.

Abdominal Palpation

Occasionally it may be possible to palpate an object that is lodged in the stomach.

Laboratory Tests

• Haematology
  • May detect dehydration and a hypoproteinaemia if the patient has a protein-losing enteropathy.
  • Anaemia due to gastric bleeding is rare
• Biochemistry
  • Hypokalaemia, hypochloraemia and hypokalaemia may be detected as a result of vomiting due to gastric outflow obstruction.

Radiography

• Plain survey radiographs of the abdomen may reveal a radiopaque object or mass within the abdomen.
• Contrast radiography in the form of a gastrointestinal barium contrast study may be indicated if plain radiographs are unremarkable.

Endoscopy

May be indicated if the plain radiographs are unremarkable. A very effective means of obtaining a definitive diagnosis.

Treatment

Small foreign object may be allowed to pass through the gastrointestinal tract if they are very unlikely to damage. However, it is advisable to remove most.

• Medical
  • Induce vomiting with apomorphine or hydrogen peroxide in the dog or xylazine in the cat. It must be ensured that the object does not have sharp edges or points that may cause trauma when expelled.
• Surgery
  • Exploratory laparotomy and gastrostomy may be performed to remove the object in cases where the induction of vomiting is prohibited. This procedure is carried out under general anaesthesia and it is essential to assess the patient's hydration and electrolyte status prior to induction.
• Endoscopic removal - Performed under general anaesthesia. Radiographs should be taken prior to this procedure to ensure that the object is still in the stomach. A flexible endoscope is required together with grasping forceps. If this is unsuccessful, exploratory laporatory and gastrostomy should be performed.

Prognosis

Good prognosis if there are no secondary effects. Poor prognosis if there is gastric perforation resulting in septic peritonitis and debilitation of the patient.

References

• Hall, E.J, Simpson, J.W. and Thomas, D. (2005) BSAVA Manual of Canine and Feline Gastroenterology (1st Edition) BSAVA

• Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier