Endoscopy & cats–the places we can go (Proceedings)

Endoscopy is a wonderful diagnostic tool that allows exploration and biopsies of areas without invasive surgery. Given the option, many clients may prefer endoscopy instead of surgery. What types of cases are suited to endoscopy? How do you prepare a cat for endoscopy? This lecture will cover those questions and more as we explore the places we can go with endoscopy. Case studies will be used to highlight certain points.

Types of scopes I use commonly in cats:

Rigid:

     • 2.7 mm Multi-purpose endoscope, 18 cm working length

Flexible:

     • Gastroscope with 2.5 mm working channel; 8.5 mm shaft diameter; 150 cm working length

     • Videoscope with 2.8 mm working channel; 8.5 mm shaft diameter; 140 cm working lengt

     • Specialty Fibroscope with 1.2 mm working channel, shaft diameter 2.9 mm; 100 cm working length

     • Bronchoscope with 2.2 mm working channel; 5 mm shaft diameter; 580 mm working length

Scopes to start with: Rigid scope, one long flexible GI scope

Areas that can be scoped:

     • Nose

     • Ears

     • Mouth

     • Pharyngeal area

     • Laryngeal area

     • Airways – Trachea, Bronchial tree

     • Upper GI – Esophagus, Stomach, Duodenum, Upper portion of jejunum

     • Lower GI - Colon up to Ileocecal colic junction

     • Vagina, Urethra and Bladder (Female cats)

     • Joints

Given all the different sizes of endoscopes available, almost any opening in the feline patient can be entered. The one exception is the urethra of the male cat.

Percutaneous approach is also a consideration (kidneys, ureters, bladder, etc.)

Preparation for Endoscopy:

Since most endoscopic procedures require general anesthesia or heavy sedation, a preanesthetic evaluation (blood work, urinalysis) is recommended. Radiographs of the chest and abdomen may also be indicated depending on the pet's clinical signs. Some radiographic studies, such as skull radiographs, are better performed under anesthesia. For areas that are very vascular (nasal cavity), consider performing coagulation tests prior to the procedure.

No barium should be given to the patient within 24 hours of the procedure, AND barium must have cleared the areas of interest. Barium will cause significant damage to the endoscope and contact between the endoscope and barium must be avoided.

What can be accomplished with endoscopy?

     - Close-up visualization of an area of interest in a non-invasive manner

     - Biopsy area of interest for histopathology, cytology, and/or cultures

     - Evaluation/Removal of foreign object(s)

     - Feeding tube placement

     - Perform diagnostic tests and therapeutic procedures in any part of the body that can be accessed endoscopically (Interventional Endoscopy), often performed in conjunction with some other imaging modality (fluoroscopy, ultrasound). Ex: urethral stenting, balloon dilatation for nasopharyngeal stenosis and esophageal strictures; tracheal stenting, lithotripsy for renal, ureteral or cystic calculi

Just a word concerning laparoscopy/thoracoscopy:

Laparoscopy can be used in the feline patient for biopsy of the liver, kidney, pancreas, or masses. Other diagnostic applications include evaluation of abdominal trauma, bile duct patency, response to therapy, or abnormal radiographic findings. Laparoscopic surgery can also be performed, including hernia repair and OVH. Thoracoscopy may be indicated in cases of pleural effusion, pericarditis, pericardial effusion, mediastinal disease, abnormal radiographs findings, biopsies and culture.

Cases suited for endoscopy (from head to toe):

Rhinoscopy may be indicated in cats with nasal discharge, nasal obstruction (one of both nasal passages), chronic sneezing, nasal stertor, epistaxis, facial distortion, nasal pain, acute severe sneezing, mass/polyp biopsy and abnormal radiographs. Both rigid and flexible endoscopes may be used for rhinoscopy.

For otoscopy, indications include chronic discharge in one or both ears, foreign object removal, determination of tympanic membrane integrity, fluid removal and mass/polyp biopsy. Typically rigid endoscopes are used for otoscopy.

Bronchoscopy is indicated in certain cases of bronchitis, coughing, pulmonary neoplasia, tracheal collapse, stridor, foreign body removal and other abnormal breathing patterns. Both rigid and flexible endoscopes may be used for evaluation of the airways (larynx, trachea, bronchi).

For gastrointestinal endoscopy, a partial list of indications includes regurgitation, dysphagia, salivation, nausea, vomiting, hematemesis, melena, anorexia, diarrhea, weight loss, hematochezia, fecal mucus, tenesmus and foreign body removal. Flexible endoscopes are used for esophagoscopy, gastroduodenoscopy and colonoscopy.

Urethrocystoscopy is indicated in patients presenting with chronic cystitis, pollakiuria, hematuria, stranguria, incontinence, trauma, calculi, and abnormal radiographs.

Indications for vaginoscopy and colposcopy (endoscopy of the cervix) include vaginal discharge, bleeding or masses, trauma, incontinence, foreign body removal and stranguria.

Arthroscopy may be indicated in some cases of feline osteoarthritis.

Selected readings

Caccamo R, Twedt DC, Buracco P, et al: Endoscopic bronchial anatomy in a cat. J Feline Med Surg 9(2):140-9, 2007.

Elle M, Sabo M: Basics in canine and feline rhinoscopy. Clin Tech Small Anim Pract 21(2):60-3, 2006.

Esterline ML, Radlinsky MG, Schermerhorn T: Endoscopic removal of nasal polyps in a cat using a novel surgical approach. J Feline Med Surg 7(2):121-4, 2005.

Johnson LR, Drazenivich TL: Flexible bronchoscopy and bronchoalveolar lavage in 68 cats (2001-2006). J Vet Intern Med 21(2):219-25, 2007.

Kovak JR, Ludwig LL, Bergman PJ, et al: Use of thoracoscopy to determine the etiology of pleuraleffusion in dogs and cats. J Am Vet Med Assoc 221(7):990-4, 2002.

Messer JS, Chew DJ, McLoughlin MA: Cystoscopy: techniques and clinical applications. Clin Tech Small Anim Pract 20(1):52-64, 2005.

Moore LE: The advantages and disadvantages of endoscopy. Clin Tech Small Anim Pract 18(4):250-3, 2003.

Nicastro A, Walshaw R: Chronic vaginitis associated with vaginal foreign bodies in a cat. J Am Anim Hosp Assoc 43(6):352-5, 2007.

Posner LP, et al: Use of propofol for general anesthesia in cats with primary hepatic lipidosis. J Am Vet Med Assoc 232:1841-1843, 2008.

Shumway R, Broussard JD: Maintenance of gastrointestinal endoscopes. Clin Tech Small Anim Pract 18(4):254-61, 2003.

Staiger BA, Beale BS: Use of arthroscopy for debridement of the elbow joints in cats. J Am Vet Med Assoc 226(3):401-3, 2005.

Van Nimwegen SA, Kirpensteijn J: Laparoscopic ovariectomy in cats: comparison of laser and bipolar electrocoagulation. J Feline Med Surg 9(5):397-403, 2007.