Page 250 - Clinical Manual of Small Animal Endosurgery

238 Clinical Manual of Small Animal Endosurgery

endoscopy. Serology may have a high degree of cross-reactivity with
other forms of antigenic stimulation (specifically neoplasia); however,
even with these limitations there is clinical utility to this test.
In cases where large airway disease is suspected it is advised that cervi-
cal and thoracic radiographs be performed. This step is critical in
differentiating lower and upper airway disease prior to general anaesthe-
sia. Mass lesions suspected in the cervical neck and thorax may be well
visualised with ultrasound imaging.

Diagnostic work-up under general anaesthesia

Once the appropriate pre-anaesthetic workup has been completed and
the potential utility of endoscopy has been established, the patient can
be placed under general anaesthesia. This presumes that no specific con-
traindication to general anaesthesia is noted.
With the patient anaesthetised additional imaging studies can be
obtained. Where available, computed tomography (CT) and magnetic
resonance imaging (MRI) are excellent modalities for examining the
rhinarium, paranasal sinuses and brain case. In an ideal situation, these
studies can be scheduled concurrently with anticipated endoscopy. More
often than not, the need for referral to secondary or tertiary referral
practices makes this impossible. However the availability of these
advanced imaging modalities is increasing, and access to CT and MRI
should be explored.
Radiography of the skull for evaluation of the rhinarium, paranasal
sinuses and cervical neck is still standard for this diagnostic work-up in
the absence of easy access to CT and MRI. The advent of digital radi-
ography has made doing these studies faster, easier and more reliable.
Standard views include the lateral nasal, open-mouth ventrodorsal and
the frontal sinus skyline views (Fig. 8.4). The presence of soft-tissue
densities in abnormal locales, bony lysis or proliferation, or changes in
radiographic symmetry from one side to the other helps the endoscopist
plan the procedure(s).
A more detailed oropharyngeal exam can now be done with the patient
under anaesthesia. Digital palpation of the upper dental arcade, looking
for loose teeth, pockets of subgingival purulent material and soft, pliable
maxillary bone are all important observations. If available and clinically
indicated, dental radiographs can be taken.
Similarly, digital palpation of the hard and soft palates can detect
subtle changes in tissue characteristics from one area to another. An
ovariohysterectomy hook can be utilised to reflect the caudal edge of the
soft palate cranially to allow for better visualisation of the dorsal
pharynx. It is very difficult to visualise the posterior nares using this
technique alone.