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What's New in Avian Endoscopy

A Personal Perspective
by Michael Taylor DVM

Service Chief, Avian and Exotic Medicine
Small Animal Clinic Veterinary Teaching Hospital
Ontario Veterinary College University of Guelph


In this seminar I hope to encourage you to think about how contemporary aviculture operates and to consider new pathways for the future

STRESS: define and explain in real world context:

  • Additive Effect
  • Overcrowding
  • I've got the bird but I don't have a cage yet
  • Housing too close to certain species
  • Privacy, Visual barriers
  • Other Environmental Factors: humidity, ventilation, temperature, lighting

Introduction of new birds to the aviary

Inbreeding, poor genetic records, mutation frenzy, hybridization

Individual Parrot Identification

Sex Identification:

METHODS OF SEX IDENTIFICATION IN MONOMORPHIC BIRDS: Which One Should I Choose?

 
 
ENDOSCOPY
CHROMOSOME ANALYSIS
DNA PROBE

HOW?

Visual examination of the gonad(s). Examination of the W and Z (sex) chromosomes.

Identification of specific DNA fragments related to the W and Z chromosomes.

ADVANTAGES?

Identification of gonadal activity (past and present).

Identification of ongoing disease processes (liver, kidney, adrenal, air sacs, lung, spleen, proventriculus, intestines).

Rapid results.

More efficient third party certification.

Detection of chromosomal abnormalities (structural such as inversions, translocations and triploidy). Small blood sample only, once "fixed" requires no special handling.

DISADVANTAGES?

Anesthetic/Surgical Complications

Inexperience of the surgeon

Special handling and shipping. Only one lab in North America.

Results in 2 - 3 weeks.

Identifies chromosomal abnormalities and gender only.

Identifies gender only.

Results in 2 - 4 weeks.


Aviculturalists must be able to indentify the sex of the parrots in their collections as a prerequisite to encouraging them to breed. Three techniques are now available to achieve this result and each arrives at the answer in a different way. We believe that an understanding of how each compares and contrasts will enable our clients to make the best choice to meet their needs.

I began work with fine diameter endoscopes in birds in l980 and was immediately struck by the potential of their precision optics to allow the veterinarian to examine and explore the avian patient in a way not possible in mammals. The unique anatomy of the avian respiratory system allows simplified examination of much of the body cavity while causing very little trauma. I also soon recognized that we were being presented with many outwardly normal birds for "sexing" that had ongoing internal disease problems! I came to appreciate several things from this early work, the two most important of which were that birds (as with most wild species) will do everything they can to appear outwardly normal and that early detection of disease problems increased my ability to help birds survive. When one of our avicultural clients presented a bird for gender identification we made sure that we performed a complete examination of visible structures (air sacs, lung, liver, kidney, proventriculus, spleen). It takes slightly longer to complete these checks but we now know that this extra information is very valuable both to us and to our clients.

Figures from 1992 illustrate the type of picture we have been seeing for the past 8-10 years and probably better than words explain why I believe endoscopy remains an extremely useful and cost effective part of the new bird evaluation for the aviculturalist:

Number of birds presented for "sexing" : 271

Number of birds with lesions noted: 26

Conclusion:

One in every eleven birds had medical findings that would otherwise not have been detected using one of the other methods of sex identification.

A new endoscopic sheath system developed by the author (see following paper) in association with Karl Storz Endoscopy permits the collection of targeted tissue biopsies and exudate specimens with greater ease and accuracy and with less patient trauma than was previously possible. This means that if an abnormality is found at the time of endoscopic examination a specimen (sample) may be collected for further examination and a definitive diagnosis can often be made where this was not possible before. We are very excited about the potential of this new instrumentation to help birds!

EARLY + DIAGNOSTIC SAMPLES = A HIGHER PERCENTAGE OF DIAGNOSIS OF QUALITY SUCCESSFUL OUTCOMES


 



Endoscopic Biopsy: Principles and Practice

by Michael Taylor DVM

(Reprinted courtesy Association of Avian Veterinarians 1994 Laboratory Proceedings)


Rigid, fiberoptic endoscopes have been employed in avian medicine since the l970's. The superb optical qualities of modern, fine diameter, rod lens endoscopes combined with the unique anatomic attributes of the avian air sac system have ensured that endoscopy has become a clinically valuable tool for the avian practitioner. Used initially for the examination of various tissues and the identification of sex in monomorphic birds the role of the endoscope as a diagnostic aid was gradually expanded in the early l980's by workers such as Satterfield 1, Kollias 2 and Harrison 3. They described several biopsy techniques with particular emphasis on the liver. The most widely employed technique involved introducing a rigid biopsy forcep alongside the endoscope through a single puncture.2 The forcep was carefully "walked" into position along the shaft of the telescope. Precise placement of the forcep was frequently difficult to achieve and iatrogenic trauma could result from these manipulations. Lumeij was the first to describe the use of a larger diameter trocar sleeve to facilitate the introduction of a telescope and biopsy instrument through a single puncture.4

In 1988 we began the search for improved endoscopic instrumentation applicable to birds, convinced that the technology was not being used at anywhere near its potential. We realized that all the equipment available up to that time had been adapted from human arthroscopic and ENT sources but not always with the needs of the avian practitioner in mind. Our primary focus became a single puncture system to enhance the clinician's ability to safely collect diagnostically representative specimens of observed lesions. A single puncture approach was chosen due to its simplicity and versatility. We visualized an endoscope and sheath with an integral instrument channel. The channel would allow the precise and guided placement of a variety of flexible instruments within the visual field with markedly reduced concern for manipulative trauma. A 2.7 mm telescope (a) was chosen as the optic for the system due to its good compromise between diameter and light transmission capabilities. A thirty degree forward oblique angle of view was selected to facilitate instrument viewing and guidance. Maximum flexibility is maintained because the telescope can be used on its own for diagnostic visualization. The sheath design (b) employed is an excellent balance of size, cross sectional shape and instrument carrying capacity making it useful for pet birds weighing l00 grams or more. The instrument channel will accept flexible implements up to a diameter of 5 French (1.7 mm). We have investigated a variety of instruments for use with this system. Biopsy forceps with round (c) or elliptical (d) cups are useful for organ biopsy or harvesting air sac or peritoneal debris. Grasping forceps are available in fine (3 Fr) (e) and heavy (5 Fr) (f) versions. A long, flexible 22 g needle (g) is useful for guided aspiration of cystic structures and organs such as the spleen.

APPLICATIONS

Techniques for pulmonary biopsy with this system have been previously described.5 We found that the sheath and telescope enhanced the collection of lung biopsies from an intercostal approach as well as from the caudal thoracic air sac. The confluent pleural/air sac membranes may be carefully incised using the tip of the fine needle (g) allowing easier biopsy collection from the caudal thoracic air sac approach.

Liver biopsies were obtained via a direct ventral hepatic peritoneal cavity approach as well as from the caudal thoracic air sac.6,7 During endoscopic examinations of the caudal thoracic air sac for diagnostic purposes the left (or right) lateral border of the liver can be examined. It may be advantageous to collect a biopsy of the liver from this site. A small tear must made through the closely applied air sac and VHPC walls to access the liver.7 This approach is contraindicated in patients with ascites because fluid may drain into the cranial portion of the air sac and from there into the lung leading to respiratory compromise.

Renal biopsies were collected primarily from the caudal thoracic air sac approach to the abdominal air sac.6,7 All three divisions of the kidney may be accessed from this site. The sheath system greatly facilitates the placement of instrumentation through a secondary air sac wall. The caudal division of the kidney may also be approached via a post ischial entry into the caudal portion of the abdominal air sac.4,6,7 The round 5 Fr cup biopsy forceps (c) may be preferred in smaller patients or where the clinician wishes to control the depth of tissue penetration. The elliptical or "spoon" shaped forceps (d), while of the same external diameter, have a longer, deeper cup. These forceps are recommended for the majority of liver, kidney and lung biopsies.

The 3 Fr grasping forceps (e) have fine jaws and can be employed for blunt dissection or for grasping small objects. The heavier 5 Fr grasping forceps (f) are most suitable for foreign body retrieval. Foreign bodies can be removed from the crop using this system.7 It is advisable to insufflate the ingluvies using a soft rubber catheter.

The proventriculus may be entered and explored from a midline ingluviotomy.7 The distal esophagus is entered on the midline and the sheath and telescope guided distally into the proventriculus and the ventriculus. Foreign bodies may be removed using either of the grasping forceps. Saline or air may be instilled into the viscus to aid in visualization. One of the infusion ports on the sheath may be used or a catheter can be placed, either through the instrument channel or alongside the sheath.

Three clinical cases are presented to demonstrate the diagnostic usefulness of endoscopic examination with facilitated specimen collection. In each case, the final diagnosis would have been difficult or impossible to achieve without this instrumentation.

CASE 1

A mature, male Congo African Grey Parrot was presented with a history of difficult breathing and lethargy. On physical examination the bird evidenced moderate inspiratory and expiratory dyspnea. The pectoral muscle mass was moderately reduced. A radiograph revealed bilateral, diffuse, increased densities in the cranial thoracic and caudal thoracic air sacs. A complete blood count was performed and revealed a leukocytosis with heterophilia.

The bird was anesthetized with isoflurane and oxygen and intubated with a 3.5 mm uncuffed endotracheal tube. A standard approach caudal to the last rib was used 6 but the telescope entered the abdominal air sac. The air sac was markedly inflamed and contained scattered foci of yellow caseous debris. The left caudal thoracic air sac was entered from the abdominal and was found to be somewhat reduced in size. It was almost filled with a similar yellow, caseous material. Two samples of this material were collected for cytology, histology and culture using the 5 Fr elliptical cup forceps. Branching septate hyphae were visible on Diff Quick stained smears. H and E stained sections of the debris revealed a considerable amount of necrotic debris with a pleocellular inflammatory infiltrate. Numerous fungal hyphae morphologically consistent with Aspergillus species were present. Culture of the material yielded Aspergillus fumigatus.

CASE 2

A five month old Blue and Yellow Macaw (Ara ararauna) was referred with a history of not weaning normally, weight loss and increased lethargy. The bird had maintained a markedly increased uric acid level (1200 - 1500 umol/l) for several weeks.

The bird was anesthetized with isoflurane and oxygen and intubated with a 5.5 mm uncuffed endotracheal tube. The caudal thoracic air sac was entered as previously described. Visible portions of the proventriculus, caudal border of lung, air sacs and the liver appeared normal. The abdominal air sac was entered by pressing the oblique tip of the telescope through the confluent walls of the caudal thoracic and abdominal air sacs. The left cranial, middle and caudal divisions of the kidney were pale beige to white, moderately swollen and irregular in contour with occasional white flecks on the serosal surface. The telescope was removed and the sheath attached. The unit was reinserted and a biopsy was collected from the caudal division of the kidney. Histopathology revealed a variable amount of tubular and interstitial mineralization present throughout the biopsy. It was estimated that less than 25 per cent of the parenchyma appeared normal in the section. No evidence of any infectious condition was seen. The degree of mineralization seen was felt to be most consistent with hypervitaminosis D. On close questioning of the owner it was discovered that a large amount of multivitamin supplement was being added to a commercially available, balanced hand feeding formula in the mistaken belief that this was necessary and that
if a little bit was good, a large amount must be great!

CASE 3

A mature Yellow Headed Amazon (Amazona ochrocephala) was presented with a history of decreased appetite and lethargy of one week's duration. On physical examination the bird exhibited a mild to moderate decrease in plumage quality, moderate pectoral muscle atrophy and a moderate increase in choanal mucus. A CBC was essentially normal (PCV low reference range, mild increase in monocytes). A biochemistry panel had a moderately elevated alkaline phosphatase level and high reference range AST and Bile Acid values.

On radiographs the cranial abdomen exhibited a moderate to marked increase in density and the intestinal peritoneal cavity appeared distended. Barium administered for contrast demonstrated displacement of the proventriculus and ventriculus to the left side but normal passage into the intestines with no visible mass. The splenic outline was normal.

The bird was anesthetized with isoflurane and oxygen and intubated with a 3.5 mm uncuffed endotracheal tube. The left caudal thoracic air sac was entered using the previously described technique. The intestinal loops were found to be moderately distended and a pale beige colour. Occasional focal granulomas of 3-5 mm diameter were observed on the serosal surface of the intestines. The liver appeared mildly enlarged with scattered white miliary foci. The left caudal border of the liver was biopsied. Histopathology revealed a moderate to severe pyogranulomatous hepatitis. Scattered foamy histiocytes were present that on acid fast staining were positive for mycobacteria.

We have found this new system to offer greater flexibility and improved handling compared to previous instrumentation available for avian patients. The collection of quality diagnostic specimens is facilitated encouraging the timely use of endoscopy and biopsy. It has been my experience that the decision to biopsy is frequently made too late in the disease process to be truly helpful to the patient and client. Sampling the end stage organ is seldom illuminating beyond confirming a poor prognosis that should be otherwise clinically evident. Early detection of pathology coupled with increased etiological accuracy encourages prompt, effective treatment enhancing patient recovery.

(a) 2.7 mm, 30 degree forward/oblique telescope 64018 BS

(b) 14.5 Fr sheath with 5 Fr instrument channel 67065 C

(c) 5 Fr round cup flexible biopsy forceps 27071 Z

(d) 5 Fr elliptical cup flexible biopsy forceps 67161 Z,

(e) 3 Fr grasping forceps 27071 TJ

(f) 5 Fr grasping forceps 26161 T

(g) 22 g flexible fine needle 27071 X

all manufactured by: Karl Storz GmbH, Tuttlingen, Germany

distributed by: Karl Storz Veterinary Endoscopy-America, Goleta, CA, 93117

(h) Sovereign oral feeding/ urinary catheter (sterile),

Sherwood Medical, St Louis, MO

REFERENCES:

1. Satterfield W: Early diagnosis of avian tuberculosis by laparoscopy and liver biopsy. In Recent Advances in the Study of Raptor Diseases, (eds) JE Cooper and AG Greenwood, Chiron Publications, Keighly, pp105-106.

2. Kollias GV: Liver biopsy techniques in avian clinical practice. Vet Clin North Am 14(2):287-298, 1984.

3. Harrison GJ: Endoscopy. In Harrison GJ and Harrison LR (eds): Clinical Avian Medicine and Surgery, Philadelphia, WB Saunders, l986, pp 224-244.

4. Lumeij TJ: Endoscopy. In A Contribution to Clinical Investigative Methods for Birds with Special Reference to the Racing Pigeon (Columba livia domestica). Utrecht, 1987, pp 151-166.

5. Hunter DB and Taylor M: Lung biopsy as a diagnostic technique in avian medicine. Proc AAV, New Orleans, 1992, pp 207-211.

6. Taylor, M: Endoscopy. Proc AAV, Phoenix, 1990, pp 319-323.

7. Taylor, M: Endoscopic examination and biopsy techniques. In Avian Medicine: Principles and Application. Ritchie BW, Harrison GJ, and Harrison LR (eds), Wingers Publishing Inc, Lake Worth, FL, 1994, pp 327-354.

Michael Taylor DVM

Since graduating from the Ontario Veterinary College in 1980, Dr. Michael Taylor has built up an international reputation in avian medicine. After many years of clinical practice in Toronto, Dr. Taylor joined the Veterinary Teaching Hospital at OVC this summer as Service Chief for Avian and Exotics at the Small Animal Clinic.

Dr. Taylor's contributions to avian medicine have been significant. As well as lecturing extensively and presenting short courses on endoscopy throughout North America, he has since 1989 been principal instructor for the endoscopy wet labs presented at the AAV Annual Conferences. He has developed a new endoscopic sheath system for avian medicine which has proved to be a tremendous asset in diagnosing and treating avian problems.

For the future, Dr. Taylor hopes to promote expansion of clinical services for avian patients at OVC, which will enhance and enrich the teaching program at the same time. Of course, his endoscopic research will continue.


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