Page 57 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

aspiration if they are enlarged or if there is suspicion of Selective biopsy
neoplastic disease. Cytological evaluation of these aspi- • Rhinoscopy – biopsy via scope port or biopsy instrument placed
VetBooks.ir blood count, serum chemistry profile and urinalysis, • Ultrasonography, CT or MRI – biopsy instrument placed with
rates often provides diagnostic information. A complete
alongside the scope
guidance
whilst not commonly diagnostic of a particular disorder,
should be performed to assess general health. The
complete blood count may reveal thrombocytopenia, Non-selective biopsy
anaemia or changes consistent with inflammation or • Transnasal biopsy – cup forceps, alligator forceps or plastic tubing
• ydropulsion occlude nares and flush forcefully
infection. Hyper calcaemia has been associated with
nasal adenocar cinoma, and increased serum alkaline 4.4 Nasal biopsy techniques can be used in conjunction with
diagnostic imaging or rhinoscopic visualization, or specimens
phosphatase (ALP), may accompany bony destruction may be obtained non-selectively by other techniques. It is important to
(ALP may also be elevated if associated with hyperadreno - protect the airway, collect specimens from the nasopharynx and lavage
corticism). A coagulation profile (including prothrombin fluid and to e pect haemorrhage. CT computed tomography
time (PT) and activated partial thromboplastin time MRI = magnetic resonance imaging.
(aPTT)) should be performed prior to nasal surgery. For
animals that have epistaxis as a prominent feature of their
disease, it is crucial to identify any underlying or conse- Diagnostic imaging
quent perturbations of the clotting system by assessing Results of various imaging techniques are often vital to the
platelet numbers and performing functional tests of diagnosis of nasal diseases. Radiography, CT and MRI
primary and secondary haemostasis such as buccal techniques can be performed. All imaging should be done
mucosal bleeding time, PT and aPTT, or a test of ‘global’ under general anaesthesia and performed prior to rhino-
haemo stasis such as thrombo -e las to graphy, prior to any scopy or biopsy. Several radiographic views are needed to
procedures such as biopsy or surgery. assess the nasal cavity completely because of the com-
Fungal or bacterial culture of discharge is rarely helpful. plex anatomy of the nose and skull. Radiographic views
Cultures of nasal swabs will yield normal flora and fail to should include lateral, ventrodorsal (VD) open mouth (best
differentiate between normal, non-pathological colonization for evaluating the cribriform plate), intraoral dorsoventral
and active infection. Primary nasal bacterial infection is (DV) occlusal and rostrocaudal (frontal sinus). Inter-
very rarely (if ever) observed clinically. There is usually a pretation of the radiographic images is based on subtle
primary aetiology such as a viral infection, foreign body, changes; therefore, it is important to obtain high-quality
devitalized tissue or neoplasm allowing secondary infec- radiographs (Figure 4.5).
tion. Most animals with upper respiratory bacterial
infections secondary to viral disease will respond to broad-
spectrum anti biotic therapy.
Fungal serology is often of little benefit. Determination
of an antibody titre at a given time may only indicate expo-
sure to the fungus. Fungal organisms that cause nasal
disease are ubiquitous in the environment, and exposure is
not indicative of disease. However, paired serological
samples may assist in diagnosis. A latex agglutination
test for cryptococcal capsular antigen has proven to be
valu able for the diagnosis of cryptococcosis.
Cytological evaluation of a smear of the discharge
itself may be a useful diagnostic tool, although imprinting
a slide with a tissue sample or using a small brush to
obtain an intranasal sample may provide a more accurate
diagnosis. Feline nasal cryptococcosis can be diagnosed
by cytological evaluation of nasal flushes. Imprint cytol-
ogy has been shown to identify the histological tumour
type correctly more often than brush cytology (Clercx et
al., 1996). If appropriate samples can be obtained, fungal (a) (b)
or neoplastic disease can often be diagnosed cytologi- Intraoral dorsoventral
cally. Functional tests to quantify nasal airflow are not 4.5 radiographs of the nasal
routinely performed in veterinary practice, although sub- cavity. (a) Normal middle-aged
jective qualitative assessment of nasal airflow can be dolichocephalic dog. (b) A 10-year-
helpful. Nasal resistance and transnasal pressure can old Border Collie with a nasal
be determined using rhinomanometry to detect nasal carcinoma. (c) A 2-year-old Labrador
Retriever with bilateral fungal
obstructions (Wiestner et al., 2007). However, the proce-
rhinitis.
dure can be difficult and time consuming.

Diagnosis of diseases of the nose and nasal cavities
primarily relies upon diagnostic imaging (radiography,
CT, magnetic resonance imaging (MRI)) and
endoscopy (rhinoscopy, nasopharyngoscopy) (Figure
4.4), and inspection of the oral cavity with dental
probing, and should be executed in this order (c)

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