Page 1534 - Small Animal Internal Medicine, 6th Edition

1506 PART XIV Infectious Diseases

Heart base masses developed in two dogs in a recent report chronic infection, rapidly progressive acute infection, and
(Ajithdoss et al., 2011). Dermatologic findings in both primary cutaneous coccidioidomycosis. The assays can
VetBooks.ir dogs and cats are most commonly subcutaneous nodules cross-react with antibodies against Histoplasma capsulatum
and B. dermatitidis.
(Simoes et al., 2016). If subcutaneous abscesses, nodules,
Serum antibodies develop in dogs with and without clini-
ulcers, and draining tracts occur, they are usually associ-
ated with infected bones. Over 50% of the cats with skin cal signs of disease, and titer magnitude failed to correlate
lesions and over 75% of the dogs with cutaneous manifes- with the presence of illness in one study (Shubitz et al.,
tations also have systemic illness (Simoes et al., 2016). In 2005). Thus results of antibody test results alone should not
some dogs, coccidioidomycosis has been initially misdiag- be used to make a definitive diagnosis. The combination of
nosed as a malignancy (Ramirez-Romero et al., 2016). Of positive serologic test results and radiographic signs of inter-
the three cases described in this report, one was infected stitial lung disease, dermatologic disease, or osteomyelitis in
by C. posadasii. Myocarditis, icterus, renomegaly, spleno- animals from endemic areas can be used to make a presump-
megaly, hepatomegaly, orchitis, epididymitis, keratitis, iritis, tive diagnosis if the organism cannot be demonstrated. In
granulomatous uveitis, and glaucoma are detected in some one study of 131 dogs, hilar lymphadenopathy was assessed
dogs. Depression, seizures, ataxia, central vestibular disease, as a predictor of a positive serum antibody titer and was
cranial nerve deficits, and behavioral changes are the most shown to have a sensitivity, specificity, positive predictive
common signs of CNS infection. Solitary CNS granulomas value, and negative predictive value of 28%, 91.5%, 43.8%,
can occur (Bentley et al., 2015). and 84.4%, respectively (Crabtree et al., 2008). The authors
In one review, the median age of cats with coccidioido- concluded that, in endemic areas, the presence of hilar
mycosis was 5 years; no obvious sex or breed predilection lymphadenopathy in dogs in endemic areas suggested treat-
existed (Greene et al., 1995). The most common clinical ment was indicated while waiting for serum antibody test.
manifestations include skin disease (56%), respiratory Titers may persist for months to years after resolution of
disease (25%), musculoskeletal disease (19%), and either clinical disease.
ophthalmic or neurologic disease (19%). If ocular disease Definitive diagnosis requires demonstration of the organ-
occurs, granulomatous chorioretinitis and anterior uveitis ism by cytology, biopsy, antigen assay, culture, or amplifica-
occur in most infected cats. tion of specific DNA. The organism is often difficult to
demonstrate by cytology; transtracheal aspiration or bron-
Diagnosis choalveolar lavage is commonly negative. Extracellular
Normocytic, normochromic nonregenerative anemia; leuko- spherules (Fig. 97.3) are most commonly found in lymph
cytosis; leukopenia; and monocytosis are the most common node aspirates, draining masses, and pericardial fluid; wet
hematologic abnormalities. Hyperglobulinemia (i.e., poly- mount examination of unstained smears or periodic acid–
clonal gammopathy), hypoalbuminemia, renal azotemia, Schiff-stained smears are more suitable than dry mounts.
and proteinuria occur in some infected animals. In one study For B. dermatitidis and H. capsulatum, detection of anti-
of 87 dogs with coccidioidomycosis, azotemia (13%) and gens of the fungi in serum or urine has shown some clinical
proteinuria (63%) were common (Mehrkens et al., 2016). Of utility (see appropriate sections of this chapter). In humans,
the 24 dogs with renal histopathology performed, 13 dogs detection of C. immitis antigen in serum or urine shows
had lesions suggestive of immune complex glomerulone- promise as a diagnostic procedure. However, when C. immitis
phritis. Thus dogs with proteinuria that have visited endemic
areas like Arizona and California should be evaluated for
infection.
Diffuse interstitial lung patterns are more common than
bronchial, miliary interstitial, nodular interstitial, or alveo-
lar patterns radiographically in dogs and cats with respi-
ratory coccidioidomycosis. Pleural effusion from pleuritis,
right-sided heart failure, or constrictive pericarditis can
occur. Hilar lymphadenopathy is common in dogs and cats;
however, sternal lymphadenopathy or calcification of lymph
nodes is not. Bone lesions usually involve the distal diaphy-
sis, epiphysis, and metaphysis of one or more long bones,
and they are more proliferative than lytic. It can be difficult
to differentiate neoplasia from Coccidioides spp. granulomas
based on MRI findings (Bentley et al., 2015).
There are currently several methods for detection of
serum antibodies against C. immitis, including AGID, com-
plement fixation, and enzyme linked immunoassays, and FIG 97.3
tube precipitin (TP) tests. False-negative results can occur in Coccidiodes immitis spherule (20-200 µm in diameter) in
dogs and cats with early C. immitis infections (<2 weeks), muscle tissue.