Esophagoscopy

• Esophageal disease is rare in the cat but direct examination assists diagnosis.

• Examination of the esophageal mucosal surface.
• Collection of mucosal biopsy samples from the esophagus.
• Detection  and retrieval of foreign bodies Esophagus: foreign body from the esophagus.
• Esophageal stricture dilatation Esophagus: stricture.
• Detection/biopsy of esophageal masses.
• Definitive diagnosis of esophagitis  .
• Investigation of:
  • Retching.
  • Regurgitation Regurgitation.
  • Hypersalivation.
  • Anorexia.

Advantages

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

Disadvantages

• Will not detect pathology lying under the mucosa.
• Cannot carry out surgical correction compared with thoracotomy.
• Expensive equipment.

• Technical difficulty in procedures.

• Radiography Radiography: thorax and fluoroscopy contrast studies (barium series) fluoroscopy of the esophagus.
• Exploratory thoracotomy and esophagostomy Esophagostomy feeding tube placement.

Preparation

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

Procedure

• Depends on the experience of the endoscopist   →   esophagoscopy approximately 10 min.

Risk assessment

• Low 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 or rigid (for foreign body retrieval) endoscope.
• One meter insertion tube length.
• Insertion tube diameter 7-9 mm.
• ONLY use an end viewing endoscope.
• Four way tip deflection.
• MUST have cold light source with air pump 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 recording procedures and/or collecting still images.
  • Excellent as a training aid.
• Xenon light source.
• Insertion tube diameter 6-8 mm.
• Suction unit for aspiration of unwanted gastrointestinal secretions.
• Cytology brushes, grasping forceps and balloon catheters.
• More than one endoscope for examination of different parts of the gastrointestinal tract.
• Endoscope cleaning cart and sterilization unit.
• Ultrasonic cleaner for biopsy forceps.

Minimum consumables

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

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 in a well ventilated area.
  • 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 cleaning solution and disinfectant the manufacturer recommends.
  • Follow health and safety rules regarding use of these products.

• Suitable pre-medication Anesthetic premedication: overview.

• Nil by mouth for 6 hours prior to procedure.

• Light general anesthesia General anesthesia: overview.

Step 1 - Patient preparation

• Following induction of anesthesia - it is essential to intubate patient with cuffed endotracheal tube.
• Tie endotracheal tube to mandible not maxilla to assist with the passage of the endoscope.
• Lay patient in left lateral recumbency.
• Place mouth gag to protect endoscope.

Step 1 - Endoscopic examination

• Insert endoscope along hard palate and into proximal esophagus  .
• Stop and gently inflate esophagus with air.
• Once mucosa is visualized stop inflating with air.
  Do not over-inflate.
• Slowly pass endoscope along the esophagus examining the mucosa as you proceed.
• Examine the entire length of the esophagus.
• Distal esophagus is recognized by presence of annular mucosal rings     .

Step 2 - Biopsy collection

• Do not over-inflate esophagus as this will make mucosa stretch tightly reducing ability to collect samples.
• Forceps with a needle may aid procurement of biopsies.
• 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 can occur if this is done too frequently.
• Capillary bleeding from biopsy sites is normal.

Step 1 - Remove endoscope

• Gently withdraw endoscope.
• 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 over-inflate esophagus.
• Apply only enough air to allow adequate visualization.

Potential complications

• Esophageal perforation from applying too much force
• Iatrogenic damage to mucosa caused by advancing endoscope along esophagus.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Kundrotas L W, Young G S, Lang K A et al (1995) Felinization of the esophagus. Gastrointest Endosc 42 (1), 37-40 PubMed.
• Michels G M, Jones B D, Huss B T et al (1995) Endoscopic and surgical retrieval of fishhooks from the stomach and esophagus in dogs and cats - 75 cases (1977-1993). JAVMA 207 (9), 1194-1197 PubMed.

Other sources of information

• 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.
• Tams T R (1990) Small Animal Endoscopy. C V Mosby, St Louis.