Page 1536 - Small Animal Internal Medicine, 6th Edition

1508 PART XIV Infectious Diseases

include depression, behavioral changes, seizures, blindness,
circling, ataxia, loss of sense of smell, and paresis depending
VetBooks.ir on the location of the lesion; peripheral vestibular disease
can also occur. When pain from cryptococcosis occurred in
cats, it was generalized or localized to the thoracolumbar
spine or pelvic limbs in one study (Sykes et al., 2010). Non-
specific signs of anorexia, weight loss, and fever occur in
some infected cats.
Clinical findings in dogs with cryptococcosis depend on
the organ systems involved and are similar to those that
occur in the cat. Cryptococcosis is diagnosed most com-
monly in young purebred dogs. Clinical manifestations
include signs of upper or lower respiratory tract infection,
disseminated disease including intraabdominal masses, CNS
disease, disease of the orbit or eye, skin lesions, nasal cavity
disease, and lymph node involvement. Seizures, ataxia,
central vestibular syndrome, cranial nerve deficits, and clini-
cal signs of cerebellar disease are the common CNS mani-
festations in dogs (Sykes et al., 2010). Dogs with Cryptococcus
spp.–associated pyelonephritis (Newman et al., 2003) and
gastrointestinal disease (Graves et al., 2005) have been
reported. Abdominal cryptococcosis, responsive to flucon-
azole therapy without surgery, was recently reported in two
dogs (Tangeman et al., 2015). One dog had primary alimen-
FIG 97.4 tary cryptococcosis alone and the other dog pancreatic and
Nasal cryptococcosis in a cat in Colorado. disseminated cryptococcosis.
Diagnosis
have been infected, but young cats are generally overrepre- Nonregenerative anemia and monocytosis are the most
sented. In one study in Australia, Siamese, Himalayan, and common hematologic abnormalities; neutrophil counts and
Ragdoll breeds were overrepresented (O’Brien et al., 2004). biochemical panels are generally normal. In dogs with CNS
Infection of the nasal cavity, resulting in sneezing and nasal involvement, CSF protein concentrations vary from normal
discharge (Fig. 97.4), is reported most frequently. The nasal to 500 mg/dL and cell counts vary from normal to 4500/µL;
discharge can be unilateral or bilateral, range from serous to neutrophils and mononuclear cells predominate, but eosino-
mucopurulent, and often contains blood. Granulomatous phils are present in some cases. Imaging changes consistent
lesions extruding from the external nares, facial deformity with cryptococcosis include increased soft tissue density
over the bridge of the nose, and ulcerative lesions on the in the nasal cavity caused by fungal granuloma formation,
nasal planum are common; mandibular lymphadenopathy is as well as nasal bone deformity and lysis. Hilar lymph-
detected in most cats with rhinitis. These signs are also adenopathy and diffuse to miliary pulmonary interstitial
common in cats with upper airway lymphoma and feline patterns are common thoracic radiographic abnormalities.
aspergillosis, so every effort should be made to obtain a Because circulating Cryptococcus spp. antibodies can
diagnosis before instituting treatment. The nasopharynx is be detected in both healthy and diseased animals, their
the primary site of involvement in some infected cats and presence does not document clinical disease. In addition,
dogs, resulting in snoring and stertor as the predominant in one study all infected cats were seronegative (Flatland
clinical signs. Cryptococcus gattii has also been detected in et al., 1996). Cryptococcal antigen can be detected in serum,
pleural effusion (Barrs et al., 2005). aqueous humor, or CSF by a number of methods; serum
Single or multiple, small (<1 cm), cutaneous or subcuta- antigen tests are positive in most cats and dogs infected
neous masses also have been reported commonly in cats by C. neoformans. For example, 51 of 53 cats and 15 of
infected with C. neoformans. The masses can be either firm 18 dogs tested were positive for serum antigen in a retro-
or fluctuant and have a serous discharge if ulcerated. Ante- spective study in California (Trivedi et al., 2011a). However,
rior uveitis, chorioretinitis, or optic neuritis occurs in asso- animals with acute disease, chronic low-grade infections,
ciation with ocular infection; lens luxations and glaucoma drug-induced remission, localized disease, or infection by
are common sequelae. Chorioretinitis lesions can be punc- C. gattii can be latex agglutination (LA) test-negative (Tint-
tate or large; suppurative retinal detachment occurs in some elnot et al., 2015). The LA performed on CSF is positive in
infected cats. almost all animals with CNS cryptococcosis. Because of the
CNS signs of disease result from diffuse or focal menin- problems associated with detection of C. gattii antigen by
goencephalitis or focal granuloma formation. Manifestations some assays, culture or PCR assays should be considered in