GASTROINTESTINAL FOREIGN BODY

VetSuite  Veterinarians
Gastroenterology & Digestive Diseases -  Surgery (General & Soft Tissue)

Gastrointestinal (GI) foreign body is a term that refers to any material other than food that is ingested with resultant irritation, obstruction, laceration or penetration of the stomach and/or intestinal wall. Most commonly, foreign bodies result in partial or complete obstruction of the stomach outflow track or intestine.

DIAGNOSIS OF GASTROINTESTINAL FOREIGN BODY

ETIOLOGY AND RISK FACTORS

• Causes - GI foreign bodies can be caused by ingestion of a variety of non-food items, such as string, ribbons, toys, clothing, rocks, wood, plastic or carpet. These can all result in partial or complete GI obstruction.
• Risk factors
• Age - Dogs of any age are susceptible to developing foreign body problems, but it is most commonly seen in young dogs less than two years of age.
• Breed/genetics - Members of the retriever family tend to have a higher incidence of GI obstruction than other breeds.
• Sex - No known risk
• Geographic/environmental - Dogs in homes with small children may be at increased risk because of access to toys.
• Other medical disorders - No known risk

• Prevention - The best way to prevent GI foreign bodies is to prevent access to objects that could be swallowed. Diagnosis and treatment of medical conditions causing pica, such as portosystemic shunts or separation anxiety, should also be pursued if suspected.

HISTORY AND CLINICAL SIGNS

• Species affected - Dog and cat
• Presenting signs and historical problems - Dogs are sometimes presented immediately following ingestion when ingestion is witnessed by the owner. In these cases, there are usually no clinical signs. If, however, ingestion is not witnessed, the dog may present days later with vomiting, anorexia, lethargy, dehydration, diarrhea, lack of feces and/or ptyalism.

PHYSICAL EXAMINATION FINDINGS

• General
• Attitude - Mental status may vary depending on when the pet is examined following ingestion. Dogs can range from being alert and active to depressed or even comatose.
• Body condition - The body condition may be poor in animals that have been anorectic or vomiting for days before examination. Emaciation may be present in animals that have had chronic partial GI obstruction.
• Vital signs - In early cases, vital signs are normal. As time passes, the vitals signs tend to deteriorate. Heart rate and respiratory rate may be elevated due to dehydration, pain or peritonitis. Some animals may have fever or hypothermia.
• Mucous membranes - Often dry and tacky. Gum color may be muddy or brick red and capillary refill time delayed.
• Hydration status - In dogs with vomiting and/or diarrhea, profound dehydration may be present.
• Head and neck - Often unremarkable
• Eyes - Unremarkable, though in cases of severe dehydration, the eyes may be sunken.
• Oral cavity - Thorough examination may reveal ptyalism and halitosis. Always examine under the tongue for a linear foreign body that may have looped around the base of the tongue.
• Thorax (cardio-pulmonary) - In advanced cases, tachycardia and tachypnea may be present. Although uncommon, cardiac arrhythmias may be ausculted. Breath sounds are often normal.
• Abdomen (gastrointestinal/urinary) - Abdominal palpation may reveal a firm mass, ascites or abdominal pain. Palpation of the foreign body usually causes abdominal pain. Distended or fluid-filled bowel loops may be palpated. Borborygmus is often reduced. A sausage shaped mass may be palpable if the foreign body has resulted in a secondary intussusception.
• Reproductive system - Unremarkable
• Lymph nodes - Unremarkable
• Integumentary system - Dehydration is commonly detected based on skin turgor.
• Neurologic examination - The nervous system is typically not affected by a GI foreign body, but the mental status of the pet may not be normal. As treatment is delayed, the mentation of the pet gradually diminishes and some pets progress to coma and death.
• Musculoskeletal examination - If chronic vomiting and anorexia have occurred, the dog may have lost muscle mass.

DIAGNOSTIC STUDIES

• Clinical laboratory tests
• CBC - The CBC may reveal an increased hematocrit due to dehydration and neutrophilia due to inflammation. More severe inflammation or peritonitis will result in a left shift.
• Serum biochemical tests - Various abnormalities may be detected, including:
  ↓ Total protein (due to dehydration)
  ↓ BUN/creatinine (due to dehydration)
  ↓ Amylase and lipase (due to complicating pancreatic inflammation)
  ↓ Potassium (from chronic vomiting)
  ↓ Chloride (from chronic vomiting)
  ↓ CO2 (from chronic vomiting)
  ↓ or ↓ Sodium (↓ due to dehydration or ↓ due to chronic vomiting)
• Urinalysis - Assuming normal renal function, urinalysis often reveals an increased specific gravity due to dehydration.
• Parasitology - Fecal examination should be performed to rule out complicating parasites.
• Microbiology - If peritonitis has occurred, bacterial culture and sensitivity of the peritoneal fluid is recommended.
• Diagnostic imaging
• Radiographs (thoracic/abdominal) - Survey radiographs will sometimes reveal the GI obstruction and will vary depending on whether the obstruction is partial or complete. Radiopaque foreign bodies are readily identified. If a radiopaque item is not the cause of the obstruction, an abnormal soft tissue density may be seen. Bowel loops may be distended with gas or filled with fluid. The small intestines may be displaced, increasing the suspicion of a foreign body. Plication may also be seen, indicating a linear foreign body. In cases of perforation, free air and free fluid may be seen in the peritoneal cavity.
• Contrast radiography - Contrast radiographs, with either Omnipaque or barium, are recommended if a GI foreign body is suspected but cannot be confirmed on survey films. The normal transit time in the dog is 90 to 240 minutes. Serial radiographs often reveal the site of obstruction, and the same lesion should repeat on successive films.
• Ultrasound (abdominal) - Abdominal ultrasound may be used to try to confirm the diagnosis of GI foreign body. Gas and fluid filled bowel loops may be seen and the motility of the GI tract can be assessed. Sometimes, the site of the obstruction can be determined. However, contrast radiography is preferred over ultrasound to confirm the diagnosis of GI foreign body.
• Ultrasound (thoracic/ECHO) -
• Ultrasound (other) -
• Nuclear imaging -
• CT/MRI -
• Other -
• Pathology
• Cytology (fluid or tissue) - If there is abnormal tissue in the area of the obstruction, an intestinal biopsy should be submitted for histopathology.
• Biopsy/histopathology - If abdominal fluid is present, perform abdominocentesis to determine if septic peritonitis is present (bacteria and neutrophils seen on cytology.)

DIAGNOSIS AND PROGNOSIS

• Differential diagnosis - A variety of diseases can cause vomiting, anorexia and lethargy. These must be ruled out to diagnose GI foreign body:
• Gastroenteritis
• Pyloric outflow obstruction
• Pancreatitis
• Gastrointestinal parasites
• Diabetes mellitus
• Renal failure
• Liver disease
• Ethylene glycol toxicity
• Lead toxicity
• Urinary obstruction
• Peritonitis
• Pyometra
• Gastrointestinal neoplasia
• Intestinal intussusception
• Intestinal torsion or volvulus
• Inflammatory bowel disease
• Recommended tests - CBC, biochemical profile, urinalysis and survey radiographs are initially recommended. If necessary, an upper GI series can be performed to confirm the diagnosis. In questionable cases, serial plain film radiographs can be helpful to see if the foreign body is moving down the intestinal tract.
• Summary of diagnostic criteria - Based on the above tests, evidence of partial or complete GI obstruction will be found. The final diagnosis is often made during exploratory laparotomy.
• Prognosis - If treated early, prognosis for recovery is excellent. If treatment is delayed and perforation and peritonitis have occurred, prognosis is guarded to poor.

TREATMENT OF DISEASE

TREATMENT PRINCIPLES

Treatment for GI foreign bodies/obstruction varies. Endoscopic removal of the foreign object or exploratory laparotomy are typical options.

INITIAL/HOSPITAL THERAPY

• Symptomatic therapy - Dogs with vomiting and anorexia are often dehydrated. Intravenous fluids are crucial for stabilization. Correction of electrolyte abnormalities is also important. In some cases, diagnostics and specific treatment may be delayed until the pet is stabilized with intravenous fluids.
  
  After removal of the foreign object, cimetidine (2.5 to 5 mg per pound intravenous every 6 hours) or famotidine (0.25 to 0.5 mg per pound intravenous or subcutaneous every 12 to 24 hours) may be recommended, based on severity of GI inflammation. Some veterinarians choose to treat the dog additionally with intravenous antibiotics such as ampicillin (10 mg per pound every 8 hours), cefazolin (10 mg per pound every 8 hours) or enrofloxacin (2.5 to 5 mg per pound intramuscular or intravenous twice daily). Following surgery, analgesics such as morphine (0.25 to 0.5 mg per pound subcutaneous or intramuscular as needed) or buprenorphine (0.0025 mg per pound intravenous or intramuscular every 4 to 8 hours) are beneficial. Metoclopramide (0.1 to 0.2 mg per pound every 8 hours) may be needed if ileus has occurred secondary to the obstruction.
• Specific therapy - Specific therapy for GI foreign body includes endoscopy or surgery. Which route is taken depends on the location of the obstruction, the severity of illness, owner finances and surgeon's/endoscopist's experience.

• Endoscopy. This method can remove foreign objects within the stomach. If a significant amount of the foreign material is located within the intestines, endoscopy may not be the appropriate choice.
  
  The advantages of an endoscopy is the absence of an incision, which makes the recovery time quicker. A disadvantages of endoscopic removal is the inability to determine if there is any residual foreign material in the intestines. Also, some types of foreign material, such as large rocks and balls, cannot be grasped by the small endoscopic grabbers.
• Surgery. Surgery is recommended if intestinal obstruction or perforation is suspected. If the pet is profoundly ill, surgery if often preferred in order to examine the GI tract and lavage the abdomen.
  
  Once the obstruction is located, gastrotomy or enterotomy is performed to remove the foreign object. Multiple enterotomies may be necessary to remove extensive foreign bodies, particularly linear foreign bodies. In severe cases, GI resection and anastomosis may be required. The incision is then closed. If contamination of the peritoneal cavity occurred during surgery, or if peritonitis is present, the abdomen should be lavaged and suctioned with copious amount of sterile saline.

LONG TERM/HOME THERAPY

Following discharge, the dog may require continued stomach protectants, antibiotics and analgesics. Avoid NSAIDS or steroids until the GI tract has healed (10-14 days). The dog should be fed a bland diet for 3 to 5 days and gradually returned to a normal diet. Access to foreign objects should be avoided and the owner should dog-proof his home thoroughly.

FOLLOW-UP CARE

Following discharge, the dog should be examined in 7 to 10 days for suture removal and examination. Anorexia, vomiting or lethargy following foreign body removal requires diagnostics and treatment. Do not assume that the dog is just slow to heal. Perforation, dehiscence and peritonitis can occur following enterotomy or gastrotomy and need to be diagnosed and treated promptly and aggressively.