Enteroscopy

• Examination of the intestinal mucosa.
• Collection of intestinal biopsy samples.
• Collection of duodenal aspirate for bacterial culture, small intestinal bacterial overgrowth (SIBO) detection.
• Investigation of:
• Weight loss.
• Chronic diarrhea.
• Vomiting.
• Melena.

Advantages

• Non-invasive technique requiring no surgical intervention.
• Well tolerated by sick cats which would be unsuitable for laparotomy.
• Requires only light general anesthesia   →   rapid recovery.
• Good visualization of the alimentary mucosa.
• Follow up examination well tolerated and useful for to assessing response to treatment.

Disadvantages

• Will not detect pathology lying under the mucosa.
• Not routinely possible to examine the distal jejunum and the ileum.
• Cannot carry out surgical correction compared with laparotomy.
• Expensive equipment.

• Technical difficulty in procedures.

• Radiography Radiography: abdomen and fluoroscopy contrast studies (barium series) fluoroscopy of the alimentary tract.
• Ultrasonography and ultrasound-guided aspiration.
• Exploratory laparotomy Laparotomy: midline.

Preparation

• Induction of anesthesia and/or sedation   →   10-30 min.

Procedure

• Depends on the experience of the endoscopist   →   approximately 30-40 min.

Risk assessment

• Medium risk.
• See complications.

Nursing expertise

• Good level of competence required for assisting in procedures, monitoring anesthetic and assisting in biopsy collection and handling.
• High competence for care and cleaning of endoscopic equipment

Minimum equipment

• Fully immersible fiber optic flexible endoscope.
• 1.5 meter insertion tube length.
• ONLY use an end viewing endoscope.
• Outside diameter of insertion tube 6-7 mm to aid intubation of duodenum.
• Four way tip deflection.
• MUST have cold light source with air pump, suction and water wash facility.
• Fenestrated biopsy forceps for collection of mucosal biopsy samples.
• Cleaning brushes for biopsy channels.
• Water leakage tester.

Ideal equipment

• video endoscope:
• Excellent magnified image presented on screen.
• Detection of lesions much easier.
• Allows for multiple person viewing.
• Excellent for video recording procedures and/or collecting still images.
• Excellent as a training aid.

• Xenon light source.
• Insertion tube diameter 6 mm or 7 mm.
• Suction unit for aspiration of unwanted gastrointestinal secretions.
• Cytology brushes.
• More than one endoscope for examination of different parts of the gastrointestinal tract.
• Endoscope cleaning cart.
• Ultrasonic cleaner for biopsy forceps.

Minimum consumables

• Clean water.
• Endoscope disinfectants.
• Household detergent.
• Formal saline, card and containers for preservation of biopsy samples.

Ideal consumables

• Endoscopic (Portex) catheters for collection of small intestinal aspirates.
• Collection bottles for duodenal aspirates.

Other requirements

Care and maintenance

• Storage of endoscopes:
• ALWAYS store endoscopes in a safe location where accidental knocks can be avoided.
• ALWAYS store endoscopes with insertion tube hanging vertically.
• Do NOT store endoscopes in their carrying case.
• See supplier for further details of endoscope 'hangers'.

• Cleaning and disinfection Endoscope: cleaning:
  • Follow the manufacturers recommendations at all times.
  • Use an endoscope cleaning bath wherever possible.
  • Use whatever enzyme cleaning solution and disinfectant the manufacturer recommends.
  • Follow health and safety rules regarding use of these products.

• Suitable premedication.

• Nil by mouth for a minimum of 12 h.

• Light general anesthesia General anesthesia: overview.

Step 1 - Patient preparation

• Following induction of anesthesia - it is essential to intubate patient.
• Tie endotracheal tube to mandible NOT maxilla, to aid passage of endoscope.
• Lay patient in left lateral recumbancy.
• Place mouth gag to protect endoscope.
• Pass endoscope.
• Insert endoscope along hard palate and into proximal esophagus   .
• Slowly pass endoscope along the esophagus.

Step 2 - Enter stomach

• Once cardia is reached  gently apply force on endoscope to enter stomach.
• 'Red out' will occur during intubation of stomach. (Vision is lost).
• Once you feel the endoscope pass the cardia, STOP, gently inflate stomach with air.
• Do NOT examine the stomach but inflate with only the minimum amount of air to permit passage of the endoscope to the pylorus.
  Excessive air will close the pylorus, making duodenal intubation impossible.

Step 3 - Identify pylorus

• Pass endoscope along antrum to visualize the pylorus  .
• Bile may be observed entering the stomach as may antral peristaltic contraction.

Step 1 - Entering the duodenum

• Gently move the endoscope tip towards the pylorus, 'red out' will occur again.
• Maintain gentle pressure, do NOT force the endoscope, until resistance is reduced indicating passage into the duodenum.
  Often the 'red out' will become a 'yellow out' indicating the presence of bile and entry into the duodenum.
• At this point inflate with air until mucosa is visualized  .
• Advance endoscope along the duodenum examining the mucosa as you proceed.
• Note the mucosa has a velvet appearance which is different to the stomach.
• Collect biopsy samples from different levels of the duodenum.
• With 1.5 m insertion tubes the jejunum may be examined, but NOT the ileum.

Step 2 - Biopsy collection

• Do not overinflate the bowel as this will make mucosa stretch tightly reducing ability to collect samples.
• Try and advance biopsy forceps perpendicular to the mucosa.
• Tent mucosa before closing biopsy forceps and retrieving sample.
• Deeper samples can be collected by sampling repeatedly at the same site.
• Perforation will occur if this is done too frequently.
• Capillary bleeding from biopsy sites is normal.

Step 1 - Remove endoscope

• Gently withdraw endoscope into stomach.
• Examine the stomach at this time Gastroscopy and take biopsies.
• Withdraw endoscope from patient.
  Support end of scope as it is withdrawn to prevent damage.

General Care

• Routine post anesthetic observation.
• Check mucus membrane color, heart and respiratory rates in case of hemorrhage.
• Check there is no evidence of gastric dilation.

Special precautions

• Do not overinflate bowel. Apply only enough air to allow adequate visualization.

Potential complications

• Arterial bleeding from biopsy sites.
• Bowel perforation from applying too much force especially during intubation of duodenum.
• Iatrogenic damage to mucosa caused by advancing endoscope along bowel.

Refereed papers

• Recent references from PubMed and VetMedResource.

Other sources of information

• Tams T R (1998) Small Animal Endoscopy. 2nd edn. C V Mosby, St Louis.
• Simpson J W (1996) Gastrointestinal Endoscopy. In: Manual of Canine and Feline Gastroenterology. Eds: D Thomas, J W Simpson, E J Hall. BSAVA, Cheltenham. pp 20.
• Brearley M, Cooper J E, Sullivan M (1991) A Color Atlas of Small Animal Endoscopy. Wolfe.