Full text of DOI:10.1111/j.1939-165X.2002.tb00283.x

What Is Your
Diagnosis?
Pleural Effusion in a Dog With
Discospondylitis
Fonzie J. Quance-Fitch, Sara Schachter, Mary M. Christopher
Case Presentation
A 7-year-old, 28-kg spayed female mixed-breed dog was
presented to the Veterinary Medical Teaching Hospital
(VMTH) at the University of California, Davis for evalu-
ation of lethargy and weight loss of 6 months duration.
The dog had been diagnosed with discospondylitis,
spondylosis, and hilar lymphadenopathy by the refer-
ring veterinarian 2 months previously. A course of
antibiotics failed to alleviate clinical signs. On physical
examination at the VMTH the dog was moderately
cachectic with muscle atrophy, had severe paraspinal
pain from the cervical to midlumbar spine, and had
decreased lateral range of motion in its neck. Crepitus
was present over several joints and joint capsules were
thickened. Ventral lung sounds were decreased and a
slightly increased inspiratory effort was noted.
Prescapular and popliteal lymph nodes were mildly
enlarged. Areas of retinal hemorrhage and chorioretini-
tis were noted bilaterally on fundic exam. Radiographs
confirmed progressive lumbar endplate lysis compati-
ble with discospondylitis, mild to moderate pleural effu-
sion, hilar lymphadenopathy, and moderate thora-
columbar spondylosis. Abdominal ultrasound revealed
hepatosplenomegaly with echogenicity changes and
diffuse abdominal lymphadenopathy.
Figure 1. Direct smear of pleural fluid from a dog. Wright-Giemsa,
bar=10 µm.
Results of a CBC revealed mild nonregenerative
anemia (HCT 26.1%, reference interval 37%-55%; reticu-
locytes 59,840/µL, reference value >60,000/µL if anemic),
mild lymphopenia (651/µL, reference interval 1000-
4800/µL), and moderate thrombocytopenia (78,000/µL,
reference interval 200,000-500,000/µL). Results of a
chemistry profile revealed hypocalcemia (8.9 mg/dL,
reference interval 9.9-11.4 mg/dL), marked hypoalbu-
minemia (1.0 mg/dL, reference interval 2.9-4.2 mg/dL),
marked hyperglobulinemia (9.7 mg/dL, reference inter-
val 2.3-4.2 mg/dL), moderately increased alkaline phos-
phatase activity (495 U/L, reference interval 15-127 U/L),
and a mild increase in gamma-glutamyltransferase
activity (13 U/L, reference interval 0-6 U/L). Moderate
proteinuria was noted, with a urine protein:creatinine
ratio of 1.72. Pleural fluid was hazy orange with a clear
Figure 2. Sediment smear of pleural fluid from a dog. Wright-
Giemsa, bar=10 µm.
yellow supernatant and a protein content of 6.4 g/dL.
The nucleated cell count was 3900/µL with 21,600
RBCs/µL. The differential cell count revealed 15% neu-
trophils, 48% lymphocytes, 14% large mononuclear
cells, and 23% eosinophils (Figures 1 and 2).
(Continued on next page)
From the Veterinary Medical Teaching Hospital (Quance-Fitch, Schachter) and the Department of Pathology, Microbiology, and Immunology
(Christopher), University of California, Davis, Calif. Corresponding author: Fonzie J. Quance-Fitch, DVM, DODMWDVS, 1219 Knight Street, Lackland Air
Force Base, TX 78236-5519 (fonzie.quance-fitch@lackland.af.mil).
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Veterinary Clinical Pathology
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Pleural Effusion in a Dog
Additional Test Results
Fine-needle aspirates of the spleen, prescapular and
popliteal lymph nodes, liver, and bone marrow were
obtained for cytologic examination. Numerous fungal
elements similar to those seen in the pleural fluid were
observed in the spleen, lymph nodes, and bone marrow
accompanied by moderate granulomatous to pyogranu-
lomatous inflammation (Figures 3 and 4). Rare branch-
ing septate hyphae also were noted in the spleen.
Additionally, moderate extramedullary hematopoiesis
was observed in the spleen, and erythroid hypoplasia
with increased iron was present in the bone marrow.
The erythroid hypoplasia, mild nonregenerative ane-
mia, and increased iron were consistent with anemia of
chronic disease or inflammation. No organisms or
inflammation were observed in the liver; however, mod-
erate hepatocellular vacuolar change with biliary stasis
was noted. Evaluation of joint fluid from the carpi
revealed moderate mononuclear reactivity with possi-
ble mild inflammation in the right carpus (10% neu-
trophils). Protein electrophoresis confirmed a polyclon-
al gammopathy. Fungal cultures of the blood, urine, and
spleen resulted in growth of Paecilomyces varoti.
Figure 3. Fine-needle aspirate of spleen from a dog with dissem-
inated Pacilomyces infection. Pyogranulomatous inflammation and
numerous fungal elements are seen. Wright-Giemsa, bar=10 µm.
Discussion
Paecilomyces is a ubiquitous saprophytic soil mold that is
rarely pathogenic to humans or animals.1 Paecilomyces is
commonly involved in food spoilage and has been the
subject of investigation for antibiotic development2-4
and insect control.5,6 In human beings, most infections
are associated with prosthesis implants or immunosup-
pression.1 Paecilomyces fungi have also been associated
with allergic alveolitis in people secondary to dust
inhalation, especially with occupational exposure dur-
ing woodcutting and grain harvesting.7,8 Paecilomycosis
caused by P varoti, P fumosoroseus, and other species have
been associated with cutaneous and systemic infections
in dogs,9-14 cats,15 turtles and tortoises,16,17 crocodiles,18
armadillos,19 nonhuman primates,20 and rodents.21
The present case of paecilomycosis was particularly
interesting because of the predominance of yeastlike
forms (phialoconidia) with rare pseudohyphaelike
structures (phialides) and relative lack of hyphae, espe-
cially in the pleural fluid.These organisms may be easi-
ly confused with Candida sp because of the presence of
both yeastlike and pseudohyphaelike forms. This
demonstrates the necessity of fungal culture in identify-
ing the specific organism. Other fungal organisms,
including Fusarium, Acremonium, Blastoschizomyces, and
Scedosporium, can also appear as sporulating forms in
tissue from infected humans.22 Several tissue forms of
these organisms may occur in vivo including hyphae,
Figure 4. Fine-needle aspirate of lymph node showing pyogranu-
lomatous inflammation and periodic acid-Schiff (PAS)-positive
fungal elements. PAS, bar=10 µm.
Cytologic Interpretation
Direct and sediment smears of the pleural fluid had a
densely stippled basophilic background consistent with
fluid of high protein content (Figures 1 and 2). Low num-
bers of RBCs were present, which were occasionally cre-
nated. Nucleated cells consisted primarily of variably
vacuolated macrophages, a few of which were binucle-
ate, small lymphocytes, and moderate numbers of
eosinophils. Occasionally, nondegenerate neutrophils
and rare mast cells also were observed. A few
macrophages were markedly distended with clear cyto-
plasm, and occasionally, macrophages were erythro-
phagocytic. Rare fungal elements were observed within
macrophages (Figure 2). They consisted of 2- to 7-µm
round, yeastlike structures and rare linear pseudohy-
phaelike structures. A diagnosis of mixed inflammatory
exudate with fungal organisms was made.
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Veterinary Clinical Pathology
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Quance-Fitch, Schachter, Christopher
toruloid hyphae resembling pseudohyphae, and unicel-
lular conidia arising from phialides.
In the rarely reported cases of paecilomycosis in
dogs,9-14 predisposing causes were not readily apparent.
As a breed, German Shepherd dogs are reported to be
predisposed to systemic fungal infections, including
Paecilomyces infection. A predisposing cause for infec-
tion was not identified in this dog. V
The eosinophilic component of the inflammation in
the pleural fluid was also of interest. Eosinophilia in
fluid has been associated with fungal infections, neopla-
sia (including mast cell tumors, lymphoma, and thymo-
ma), heartworm disease, allergic conditions, and hyper-
sensitivity reactions. With the combination of other clin-
ical findings in this dog, a high degree of suspicion exist-
ed for fungal disease; however, before finding the fungal
elements, neoplasia also was considered to be a differ-
ential diagnosis.
14
Key Words: Canine, cytology, fungus, Paecilomyces, pleural fluid
Citation: Pleural effusion in a dog with discospondylitis [pae-
cilomycosis]. Vet Clin Pathol. 2002;31:69-71.
©2002 American Society forVeterinary Clinical Pathology
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