Page 292 - Clinical Manual of Small Animal Endosurgery

280 Clinical Manual of Small Animal Endosurgery

visualisation, or, alternatively, fluids supplied via a rubber catheter and
the cloaca simply pinched closed around the endoscope’s inserted shaft.
Inside the cloaca the entrances to the rectum, ureters and in female birds
the oviduct (uterus) can be visualised. In some cases the caudal oviduct
may be entered and examined. The resultant increase in coelomic pres-
sure during cloacoscopy can result in oral regurgitation of fluid during
anaesthesia, and it is preferable that birds are intubated. Hernandez-
Divers (2006) evaluated the quality of cloacoscopically taken bursa of
Fabricius biopsies in pigeons, but found that only 30% of cases yielded
a diagnostic-quality histological sample.

Rhinoscopy
The operculum prevents entrance of endoscopes into the nares, although
the endoscope can still be used to give a magnified external view. The
alternative is to examine the caudal nasal passages entering via the
choanal slit in the roof of the upper beak inside the mouth. This may
demonstrate discharge, foreign material or parasites, such as leeches in
waterfowl.

Otoscopy
Most birds have a shallow, wide external ear canal, with a tympanic
membrane that is easily visible to the eye. External ear disease, with the
exception of trauma, is also uncommon in birds, making otoscopy of
little useful application in birds.

Oral endoscopic examination or ‘stomatoscopy’
While the oral cavity and pharynx of raptors and soft-billed birds may
be examined in consciously restrained birds, parrots will easily break an
endoscope with their powerful beak, and need anaesthesia for safe exam-
ination. Oral examination can demonstrate necrotic plaques encountered
with Trichomonas or Candida infections, Capillaria nematodes, or inju-
ries and foreign bodies.

Rigid endoscopy of the upper gastrointestinal tract
The 2.7 mm endoscope and sheath is well suited to endoscopy of the upper
gastrointestinal tract in birds, allowing one to examine the oral cavity,
oesophagus, crop (present in parrots and diurnal raptors, but absent in
owls) and proventriculus. It can be used for retrieval of some ingested
foreign bodies, such as bitten-off pieces of plastic tubing, from the crop or
proventriculus. Distension of the lumen to allow visualisation can be per-
formed by either insufflation with air via a syringe attached to the sheath,
or flushing the crop and stomach with saline after the bird has been placed
head down and intubated. Fluids used should be warmed to prevent