Page 279 - Small Animal Internal Medicine, 6th Edition

CHAPTER 14 Diagnostic Tests for the Nasal Cavity and Paranasal Sinuses 251

in addition to visualization of the nasal cavity through the
external nares.
VetBooks.ir equipment and the outside diameter of the rhinoscope. A
The extent of visualization depends on the quality of the
narrow (2- to 3-mm diameter), rigid fiberoptic endoscope
provides good visualization through the external nares in
most patients. Endoscopes without biopsy or suction chan-
nels are preferable because of their small outside diameter.
Some of these systems are relatively inexpensive. Scopes
designed for arthroscopy, cystoscopy, and sexing of birds
also work well. In medium-sized to large dogs, a flexible
pediatric bronchoscope (e.g., 4-mm outer diameter) can be
used. Flexible endoscopes are now available in smaller sizes,
similar to small rigid scopes, although they are relatively
more expensive and fragile. If an endoscope is not available,
the rostral region of the nasal cavity can be examined with
an otoscope. Human pediatric otoscopic cones (2- to 3-mm
diameter) can be purchased for examining cats and small
dogs.
General anesthesia is required for rhinoscopy. Rhinos-
copy is usually performed immediately after nasal imaging
unless a foreign body is strongly suspected. The oral cavity FIG 14.10
and caudal nasopharynx should be assessed first. During the View of the internal nares obtained by passing a flexible
oral examination, the hard and soft palates are visually exam- bronchoscope around the edge of the soft palate in a dog
ined and palpated for deformation, erosions, or defects, and with sneezing. A small white object is seen within the left
nasal cavity adjacent to the septum. Note that the septum is
the gingival sulci are probed for fistulae. narrow and the right internal naris is oval in shape and is
The caudal nasopharynx is evaluated for the presence of not obstructed. On removal, the object was found to be a
nasopharyngeal polyps, neoplasia, foreign bodies, and stric- popcorn kernel. The dog had an abnormally short soft
tures (stenosis). Foreign bodies, particularly grass or plant palate, and the kernel presumably entered the caudal nasal
material, are commonly found in this location in cats and cavity from the oropharynx.
occasionally in dogs. The caudal nasopharynx is best visual-
ized with a flexible endoscope passed into the oral cavity and
retroflexed around the soft palate (Figs. 14.9 through 14.11).

FIG 14.11
View of the internal nares (thin arrows) obtained by passing
a flexible bronchoscope around the edge of the soft palate
FIG 14.9 in a dog with nasal discharge. A soft tissue mass (broad
The caudal nasopharynx is best examined with a flexible arrow) is blocking the normally thin septum and is partially
endoscope that is passed into the oral cavity and obstructing the airway lumens. Compare this view with the
retroflexed 180 degrees around the edge of the soft palate, appearance of the normal septum and the right internal
as shown in this radiograph. naris in Fig. 14.10.