Page 270 - Small Animal Internal Medicine, 6th Edition

242 PART II Respiratory System Disorders

of the naris if airflow is obstructed, which suggests that the chorioretinitis can occur with cryptococcosis, ehrlichio-
disease is actually bilateral. Although any bilateral process sis, and malignant lymphoma (Fig. 13.4). Retinal detach-
VetBooks.ir can cause signs from one side only and unilateral disease can ment can occur with systemic hypertension or mass lesions
extending into the bony orbit. With epistaxis, identification
progress to involve the opposite side, some generalizations
of petechiae or hemorrhage in other mucous membranes,
can be made. Systemic disorders and infectious diseases tend
to involve both sides of the nasal cavity, whereas foreign skin, ocular fundus, feces, or urine supports a systemic
bodies, polyps, and tooth root abscessation tend to cause bleeding disorder. Note that melena may be present as a
unilateral discharge. Neoplasia initially may cause unilateral result of swallowing blood from the nasal cavity.
discharge that later becomes bilateral after destruction of the
nasal septum.
Ulceration of the nasal plane is highly suggestive of a
diagnosis of nasal aspergillosis (Fig. 13.2). Polypoid masses
protruding from the external nares in the dog are typical
of rhinosporidiosis, and in the cat they are typical of
cryptococcosis.
A thorough assessment of the head, including facial sym-
metry, teeth, gingiva, hard and soft palate, mandibular lymph
nodes, and eyes, should be performed. Mass lesions invading
beyond the nasal cavity can cause deformity of facial bones
or the hard palate, exophthalmos, or inability to retropulse
the eye. Pain on palpation of the nasal bones is suggestive
of aspergillosis. Gingivitis, dental calculi, loose teeth, or pus
in the gingival sulcus should raise an index of suspicion for
oronasal fistulae or tooth root abscess, especially if unilateral
nasal discharge is present. Foci of inflammation and folds FIG 13.3
of hyperplastic gingiva in the dorsum of the mouth should Photomicrograph of fine-needle aspirate of a cat with facial
deformity. Identification of cryptococcal organisms provides
be probed for oronasal fistulae. A normal examination of a definitive diagnosis for cats with nasal discharge or facial
the oral cavity does not rule out oronasal fistulae or tooth deformity. Organisms can often be found in swabs of nasal
root abscess. The hard and soft palates are examined for discharge, fine-needle aspirates of facial masses, or
deformation, erosions, or congenital defects such as clefts or fine-needle aspirates of enlarged mandibular lymph nodes.
hypoplasia. Mandibular lymph node enlargement suggests The organisms are variably sized, ranging from about 3 to
active inflammation or neoplasia, and fine-needle aspirates 30 µm in diameter, with a wide capsule and narrow-based
of enlarged or firm nodes are evaluated for organisms, such budding. They may be found intracellularly or
extracellularly.
as Cryptococcus, and neoplastic cells (Fig. 13.3). A fundic
examination should always be performed because active

FIG 13.4
Fundic examination can provide useful information in
animals with signs of respiratory tract disease. This fundus
FIG 13.2 from a cat with chorioretinitis caused by cryptococcosis has
Depigmentation and ulceration of the planum nasale are a large, focal, hyporeflective lesion in the area centralis.
suggestive of nasal aspergillosis. The visible lesions usually Smaller regions of hyporeflectivity are also seen. The optic
extend from one or both nares and are most severe disk can be seen in the upper left-hand corner of the
ventrally. This dog has unilateral depigmentation and mild photograph. (Courtesy M. Davidson, North Carolina State
ulceration. University, Raleigh, NC.)