Page 271 - Small Animal Internal Medicine, 6th Edition

CHAPTER 13 Clinical Manifestations of Nasal Disease 243

Diagnostic tests that should be considered for a dog or Most animals with intranasal disease have normal tho-
cat with nasal discharge are presented in Box 13.2. The sig- racic radiographs. However, thoracic radiographs may be
VetBooks.ir nalment, history, and physical examination findings dictate useful in identifying primary bronchopulmonary disease,
pulmonary involvement with cryptococcosis, and rare
in part which diagnostic tests are ultimately required to
metastases from neoplastic disease. They may also serve as a
establish the diagnosis. As a general rule, less invasive
diagnostic tests are performed initially. A complete blood useful preanesthetic screening test for animals that will
count with platelet count, a coagulation panel (i.e., acti- require nasal imaging, rhinoscopy, and nasal biopsy.
vated clotting time or prothrombin and partial thrombo- Cytologic evaluation of superficial nasal swabs may iden-
plastin times), buccal mucosal bleeding time, and arterial tify cryptococcal organisms in cats (see Fig. 13.3). Nonspe-
blood pressure should be evaluated in dogs and cats with cific findings include proteinaceous background, moderate
epistaxis. Von Willebrand factor assays are performed in to severe inflammation, and bacteria. Mandibular lymph
purebred dogs with epistaxis and in dogs with prolonged node aspirates may provide a diagnosis of cryptococcosis in
mucosal bleeding times. Determination of Ehrlichia spp. cats or neoplasia in dogs or cats.
and Rocky Mountain spotted fever titers are indicated for Tests to identify herpesvirus, calicivirus, and Mycoplasma
dogs with epistaxis in regions of the country where poten- felis infections may be performed in cats with acute and
tial exposure to these rickettsial agents exists. Testing for chronic rhinitis. These tests are most useful in evaluating
Bartonella spp. is also considered. Testing for feline immu- cattery problems or cats with persistent clinical signs (see
nodeficiency virus (FIV) and feline leukemia virus (FeLV) Chapter 15, Feline Upper Respiratory Infection).
should be performed in cats with chronic nasal discharge Fungal titer determinations are available for aspergillosis
and potential exposure. Cats infected with FeLV may be in dogs and cryptococcosis in dogs and cats. The test for
predisposed to chronic infection with herpesvirus or cali- aspergillosis detects antibodies in the blood. A single posi-
civirus, whereas those with FIV may have chronic nasal tive test result strongly suggests active infection by the
discharge without concurrent infection with these upper organism; however, a negative titer does not rule out the
respiratory viruses. disease. In either case, the result of the test must be

BOX 13.2

General Diagnostic Approach to Dogs and Cats with Chronic Nasal Discharge
Phase I (Noninvasive Testing)
All Patients Dogs Cats Dogs and Cats with Hemorrhage
History Aspergillus titer Nasal swab cytologic evaluation Complete blood count
Physical examination Fecal flotation (cryptococcosis) Platelet count
Funduscopic examination Capillaria/Eucoleus) Cryptococcal antigen titer Coagulation times
Thoracic radiographs Viral testing Buccal mucosal bleeding time
Mandibular lymph node Feline leukemia virus Tests for tick-borne diseases (dogs)
cytology Feline immunodeficiency virus Arterial blood pressure
Herpesvirus (PCR, virus isolation) von Willebrand factor assay (dogs)
±Calicivirus (PCR, virus isolation)
Mycoplasma felis PCR or culture
Phase II—All Patients (General Anesthesia Required)
Computed tomography (CT) or nasal radiography
Oral examination
Rhinoscopy: external nares and nasopharynx
Dental radiographs (if CT and rhinoscopy are not diagnostic)
Nasal biopsy/histologic examination
Deep nasal culture
Fungal
Bacterial (significance of growth is uncertain)

Phase III—All Patients (Referral Usually Required)
CT (if not previously performed) or magnetic resonance imaging (MRI)
Frontal sinus exploration (if involvement identified by CT, MRI, or radiography)
Phase IV—All Patients (Consider Referral)
Phase II repeated in several months using CT or MRI
Exploratory rhinotomy with turbinectomy