PROCEEDINGS OF THE NORTH AMERICAN VETERINARY CONFERENCE VOLUME 20 JANUARY 7-11, 2006 ORLANDO, FLORIDA SMALL ANIMAL EDITION Reprinted in the IVIS website (http://www.ivis.org) with the permission of the NAVC. For more information on future NAVC events, visit the NAVC website at www.tnavc.org
Exotics Reptiles and Amphibians REPTILE GASTROINTESTINAL AND RESPIRATORY ENDOSCOPY: THE NEED TO LOOK INSIDE Stephen J. Hernandez-Divers, BVetMed, CBiol MIBiol, DZooMed, MRCVS, Dipl. ACZM College of Veterinary Medicine, University of Georgia Athens, GA INTRODUCTION Endoscopy has proven to be a most useful diagnostic tool in veterinary medicine. In the field of zoological medicine, the application of diagnostic endoscopy has shown great promise in a variety of species, including reptiles. The majority of previous reports describe the use of the endoscope to examine or retrieve foreign objects from the gastro-intestinal tract. 1 There are some descriptions of coelioscopy, bronchoscopy, urogenital endoscopy, and more specific examples of particular endoscopic procedures. 2-4 Given the often small and delicate nature of exotic species, including reptiles, the continued development of minimally-invasive endoscopy appears assured. EQUIPMENT Endoscopy equipment for the practitioner has been previously reviewed. 5 See Table 1 for equipment recommendations. Telescopes & Endoscopes The 2.7mm 30 0 telescope housed within a 14.5 Fr operating sheath provides ports for irrigation and suction, as well as a 5 Fr instrument channel. The 30- degree oblique view not only enables a straight ahead view but, by simply rotating the telescope around its longitudinal axis, a much greater field of vision can be obtained. The instrument channel permits the use of various endoscopic instruments. A smaller 1.9 mm telescope with 9Fr operating sheath is also available, and the smaller 3F instruments are more appropriate for the smallest reptiles. A light source (preferably xenon), light guide cable, camera, monitor and some means of photodocumentation are also required. For larger reptiles, flexible endoscopes are preferred and various makes and models are available. Flexible bronchoscopes (2 mm and 3.8 mm) with biopsy capability are useful for respiratory endoscopy and gastro-intestinal endoscopy of smaller species. Gastrointestinal videoscopes are larger diameter, more expensive, but in addition to excellent image quality and biopsy capability, they also possess air insufflation, irrigation and suction features suitable for use in larger reptiles. The advantage of the Karl Storz flexible endoscopes is that it can be used with the same light source and camera as their rigid telescopes, thereby negating the need for a second dedicated flexible endoscopy tower. Table 1. Equipment for Gastrointestinal and Respiratory Endoscopy KARL STORZ Documentation cart with 4 adjustable shelves & locking drawer (KS, 9601) Nova xenon light source, 175-Watt (KS, 201315-20) Light guide cable, 3.5mm x 230cm (KS, 495 NA) Veterinary video camera II, soakable and gas sterilizable (KS, 69235106) Medical grade monitor (KS, 9213-B) Documentation device (e.g. AIDA-Vet or VCR or Printer) Hopkins telescope, 2.7mm x 18cm, 30º (KS, 64018 BS) Operating sheath for 2.7mm telescope, 14.5Fr (KS, 67065 C) Examination & protection sheath, 3.5mm outside diameter (KS, 64018 US) Biopsy forceps, 5Fr (KS, 69117 Z) Grasping forceps, 5Fr (KS, 67161 T) Scissors, 3Fr (KS, 62501EK) Injection needle with Teflon guide (KS, 67071 X) Wire basket retrieval device, 5 Fr flexible (KS, 67023 VK) Polypectomy snare, 5 Fr flexible (KS, 67159L) Hopkins telescope, 1.9mm x 18cm, 30º (KS, ) Operating sheath for 1.9mm telescope, 14.5Fr (KS, ) Grasping forceps, 3 Fr (KS, 61071TJ) Biopsy forceps, 3Fr (KS, 61071ZJ) Hopkins semi-rigid miniscope 1mm x 20cm, 0º (KS, 11503) 100 cm x 2.5mm flexible broncho-fibrescope (KS, 60003VB) Flexible Gastroscope (KS, ) OLYMPUS Mobile Workstation (WMN60) 2.0mm Bronchosocpe (ENF XP) 3.8mm Bronchoscope (BF3C160) 6.0mm Bronchoscope (BF1T160) 2.7mm Urethroscope (TJF160F) 5.9mm Gastroscope (GIFXP160) 8.6mm Gastroscope (GIF160) Insufflation Insufflation is essential to provide the lens-organ distance required for visualization. For gastro-intestinal endoscopy air is used and is generally delivered by a dedicated pump for flexible scopes, but an aquarium air pump can be used with a rigid telescope system. The air pump is connected to one of the sheath ports, while the second port is left open to avoid over-inflation (i.e. air is permitted to continuously escape from the sheathtelescope-animal system). Occluding this open port with a finger increases insufflation, while lifting the finger off the port decreases insufflation. By careful finger control, insufflation can be crudely controlled. 1631
The North American Veterinary Conference 2006 Irrigation When performing endoscopy within a hollow structure (e.g. bladder, oviduct, cloaca, stomach) warmed sterile saline irrigation often provides better clarity than air insufflation, and certainly provides improved mucosal detail. Fluid bags are suspended above the endoscopy table and connected to one of the sheath ports using an intravenous infusion set. A second infusion set connects the other sheath port to a collection receptacle under the table. By turning the port valves on and off the ingress and egress of saline can be controlled by the endoscopist to maintain a clean field of view. Radiosurgery & Laser As the complexity of endoscopic procedures increases so does the requirement for accurate hemostasis. The modern Surgitron 4.0MHz dual frequency radiosurgery unit (Ellman International Inc) can be connected to various endoscopy instruments that permit both monopolar and bipolar radiosurgery and represents the most economical and versatile option available. The more expensive CO 2 and diode lasers have limited applications, and more stringent human health regulations relate to their use. Until recently only the diode laser could be used down the operating channel of most endoscopes; however, a CO 2 laser probe has also been developed specifically for the 2.7mm telescope and 14.5 Fr sheath. ORAL AND UPPER GASTRO-INTESTINAL ENDOSCOPY For oral approaches to the buccal cavity and upper gastro-intestinal tract, sternal or dorsal recumbency with head and neck extended is required. It is often helpful to have the reptile raised above the table surface on foam pads or sand bags (Figure 1). The rigid telescope-sheath system can be used to examine the buccal cavity, esophagus, and stomach of small lizards, snakes, crocodilians, and chelonians. Flexible fiberscopes are required for most snakes, and larger reptiles of other orders. Air or CO 2 insufflation can be used to dilate the intestine which provides good exposure for detecting gross lesions and foreign bodies. Warm saline irrigation provides superior clarity especially when examining for mucosal detail, and tracheal intubation is essential to avoid aspiration of irrigation fluid. Whether gas or fluid is used, it is important to gently dilate the tract as the endoscope is advanced to avoid damage and laceration to the intestinal wall. CLOACAL, LOWER GASTROINTESTINAL & LOWER UROGENITAL ENDOSCOPY The reptile is positioned in dorsal recumbency with the body extended. Rigid telescopes and warm saline irrigation are preferred for cloacal endoscopy, and permits examination of the proctodeum, urodeum, and coprodeum. Detailed appraisal of the cloacal mucosa, Figure 1. (A) Gastroscopy in a savannah monitor lizard using a 2.5 mm flexible endoscope. (B) Severe esophagitis in a boa constrictor - note the petechial hemorrhages and caseous debris. (C) Gastric leiomyoma in a corn snake that presented with regurgitation. 1632
Exotics Reptiles and Amphibians Figure 2. (A) Colonoscopy of an Aldabra tortoise using an 8.6 mm flexible endoscope. (B) View of the normal colonic mucosa of an Aldabra tortoise and endoscope-guided placement of an enema tube. (C) Cloacoscopic view of a Greek tortoise demonstrating a colo-proctodeal intussusception note the caseous and necrotic surface to the tissue. urogenital papillae, and when present, the urethral opening, and oviductal openings are possible. With practice, the endoscope can be directed through the urethra into the thin-walled bladder in chelonians, and certain lizards (Figure 2). It is also possible to enter the distal oviducts of female reptiles. RESPIRATORY ENDOSCOPY Depending upon the size of the reptile, a 2.7 mm, 1.9 mm, or 1.0 mm endoscope can be used to examine the upper respiratory tract of small lizards, snakes, chelonians, and crocodilians (Figures 3 and 4). 2 It is always preferable to protect the 1.9 mm and 2.7mm rigid telescopes with a sheath but the increased diameter may be prohibitive. Rigid scopes of sufficient length can usually be directed into the lung of lizards by careful manipulation of the lizard s head, neck and body. For larger reptiles, fine diameter flexible endoscopes or videoscopes will permit a deeper examination including the lungs. 3 The reptile is positioned in dorsal or sternal recumbency, with head and neck extended. A mouth gag is recommended to guard against a lightly anesthetized reptile from biting down on the endoscope. The endoscope should be gently inserted into the glottis and then driven under direct visual control to avoid damaging the mucosa. Complete tracheal occlusion for several minutes is well tolerated by anaesthetized reptiles, and there is no need to provide alternative ventilation. A tracheal approach to the chelonian lung is particularly difficult because of the narrow trachea and sharply deviated primary bronchi. It is possible in large species (e.g. sea turtles) using fine flexible videoscopes, but not in most species. Two alternative approaches to the chelonian lung have been developed. 6 The first requires a 4mm temporary osteotomy in the carapace over the suspected lesion, pinpointed by radiography, CT or MRI. The pleuropulmonary membrane is punctured using a cannula or straight hemostats while the animal is held at maximal inspiration. Leakage of anesthetic gases confirms entry into the lung, and additional anesthetic gas scavenging should be positioned close to the pneumotomy site. The sheathed telescope can be inserted into the lung for examination. The osteotomy can be temporarily maintained with a catheter and injection cap secured within the hole, to permit intrapneumonic therapy. Alternatively, the osteotomy can be closed using an epoxy or acrylic compound (e.g. Technovite). The shell heals within 12 weeks. A second method involves a surgical approach to the septum horizontale (post-pulmonary membrane) via a craniodorsal prefemoral incision. This method is only appropriate in those species that have a well-defined membrane, which excludes most aquatic and some terrestrial species. Coelioscopy can be used to examine the ventral aspect of the lungs and confirm the existence of such a membrane prior to the surgical approach. 1633
The North American Veterinary Conference 2006 Figure 3. Endoscopic examination of the respiratory tract of a boa constrictor using a 2.5 mm flexible endoscope. (B) Endoscopic view of a snake s lung with acute bacterial pneumonia. (C) Endoscopic view of a Ball python s lung with granulomatous pneumonia due to mycobacteriosis. Figure 4. (A) Endoscopy of the right lung of a sea turtle via a transcarapacial approach using a 2.7 mm telescope. (B) Transcarapacial endoscopic view of normal chelonian lung tissue. (C) Transcarapacial endoscopic view of a pulmonary mass which is being aspirated for cytology and microbiology. 1634
Exotics Reptiles and Amphibians When present, stay sutures are placed through the caudolateral aspect of this membrane, and a sharp entry is made into the lungs. The telescope is then inserted and the endoscopic examination can proceed. Upon withdrawal, the breach in the post-pulmonary membrane must be sutured to avoid post-operative pneumocoelom. SUMMARY The benefits of endoscopy include minimally-invasive examination and sample collection, as well as targeted therapy including intralesional chemotherapy and foreign body removal, assessing response to treatment by serial examinations, and minimally invasive endosurgery. Practical experience is essential to become competent with the basic techniques that are simple to learn and will quickly open doors to ante-mortem diagnoses that were previously elusive. Furthermore, continued development of endoscopic surgery in exotic species is likely to reduce surgical morbidity, and holds considerable benefits to our small and delicate exotic patients. Endoscopy is no longer the luxury toy of the referral exotic or zoo clinician. The endoscope is an essential tool for any veterinarian dealing with reptiles (or any companion species) on a regular basis. Interested veterinarians are encouraged to seek practical hands-on instruction. References 1. Ackermann J, Carpenter JW, Using endoscopy to remove a gastric foreign body in a python. Veterinary Medicine 1995;90:761-763. 2. Divers SJ, Endoscopic evaluation of the reptile respiratory tract. Proc EAZWV 2000;303-306. 3. Hernandez-Divers SJ, Shearer D, Pulmonary mycobacteriosis caused by Mycobacterium haemophilum and M. marinum in a royal python. J Am Vet Med Assoc 2002;220:1661-1663. 4. Hernandez-Divers SJ, Diagnostic and surgical endoscopy. In Raiti P and Girling S (eds): Manual of Reptiles. British Small Animal Veterinary Association, Cheltenham, England, 2004;103-114. 5. Chamness CJ, Introduction to veterinary endoscopy and endoscopic instrumentation. In McCarthy TC (eds): Veterinary Endoscopy for the Small Animal Practitioner. Elsevier, St Louis, Missouri, 2004;1-29. 6. Divers SJ, Lawton MPC, Two techniques for the endoscopic evaluation of the chelonian lung. Proc ARAV 2000;123-125. 1635