CASE PRESENTATION
A 5-year-old, male neutered, American Staffordshire mix presented to the
Midwestern University Companion Animal Clinic (MWU CAC) for evaluation
of an acute development of labored breathing after having been
previously diagnosed with presumptive immune-mediated hemolytic anemia
(IMHA) that was treated with multimodal immunosuppressive therapy. The
presumptive diagnosis of IMHA was made at MWU CAC a month prior to the
current presentation according to the previously published consensus
statement based on the presence of severe regenerative anemia
(hematocrit 19%; RI, 36-60) with spherocytosis and a positive saline
agglutination test as well as hyperbilirubinemia.1 His
work up at the time had included repeated complete blood counts,
biochemical evaluation with serum chemistries, urinalysis, thoracic
radiographs, abdominal radiographs, abdominal ultrasound, SNAP 4Dx test
(IDEXX Laboratories, Inc., Westbrook, ME), and babesia titers (Protatek,
Mesa, Arizona). The IMHA was presumed to be non-associative based on
that work up. However, a complete work up based on consensus guidelines
to more definitively rule out associative IMHA was not performed.
Ongoing medications at the time of his last presentation included oral
cyclosporine at 5.4 mg/kg once daily, oral prednisone at 1.1 mg/kg once
daily, oral clopidogrel at 1.0 mg/kg once daily, oral clindamycin at
12.3 mg/kg twice daily, and oral enrofloxacin 11.1 mg/kg once daily.
Until 8 days prior to the last presentation, the patient had been
receiving oral cyclosporine at 5 mg/kg twice daily. He had been
receiving oral prednisone at a dose of 1.5 mg/kg daily after initial
diagnosis, which, after two weeks of therapy, had been decreased to the
1.1 mg/kg daily dose due to a stable hematocrit and medication side
effects. Clindamycin was started 6 days prior to the last presentation
after an acute onset of paw swelling and self-trauma to digits 3 and 4
of the right manus. Based on gross evaluation of the digits during
physical exam, primary consideration for the digital lesions was given
to opportunistic bacterial osteomyelitis and cellulitis secondary to
immunosuppression. No abnormalities with his digits had been noted on
any examination prior to that time. The day prior to his final
presentation, enrofloxacin was added to the patient’s antimicrobial
regimen due to progression of the digit lesions. Due to rapid clinical
decline, further cytological work up of that lesion was not pursued
prior to broadening the antimicrobial regimen.
Results of physical examination included a rectal temperature of
101.4°F, heart rate of 140 beats per minute, resting respiratory rate of
80 breaths per minute, body condition score of 7/9, and quiet to dull
mentation. Increased respiratory effort, moderate labored breathing, and
muffled heart sounds were also noted. Pain was elicited on palpation of
the right manus, which was edematous and erythematous throughout, with
open ulceration of digit 3 and mild serosanguineous discharge from nail
beds of digits 3 and 4 (Figure 2).
Cytologic smears of the discharge and fine needle aspirates from digits
3 and 4 were evaluated. Nucleated cells were found individually and in
intermediate to large aggregates that were often associated with
extracellular hyphal structures. The hyphae were irregularly septate,
exhibited acute branching and rarely would have large, round, bulbous
ends that contained fine green to black pigmentation (Figure 1). The
predominant cell population consisted of numerous degenerate neutrophils
and fewer moderate to markedly vacuolated macrophages that occasionally
exhibited leukophagia and erythrophagia. There were occasional
multinucleated giant cells seen on scanning. The digit cytology was
interpreted as marked pyogranulomatous inflammation with intralesional
dematiaceous fungal hyphae.
A CBC (Advia 2120i Hematology System) from the previous day revealed a
hematocrit of 33% (RI, 36-60), platelet count of 338 K/μL (RI,
170-400), an increased mean cell volume of 82 fL (RI, 58-79), a
reticulocytosis of 188 K/μL (RI, 0-0), a leukocytosis of 37.4 x
103 μL (RI, 4-15.5) characterized by a marked total
neutrophilia of 29,546 (RI, 2,060-10,600) with a left shift (bands
5,984/μL, RI, 0-300). No spherocytes were reported at that time. Serum
biochemistry profile through Antech Laboratories from two days prior
revealed an increased alanine transferase of 531 IU/L (RI, 12-118),
alkaline phosphatase of 4813 IU/L (RI, 5-131), gamma-glutamyl
transferase of 212 IU/L (RI, 1-12), a mild hyperbilirubinemia of 0.7
mg/dL (RI, 0.1-0.3), and a mild total hypocalcemia of 8.6 mg/dL (RI,
8.9-11.4).
Thoracic point of care
ultrasound revealed bilateral, severe pleural effusion and pericardial
effusion. Cytologic samples of the pleural and pericardial fluid showed
numerous degenerate to poorly preserved neutrophils. There were moderate
numbers of moderately vacuolated macrophages that occasionally contained
phagocytized cellular debris. Both the pericardial and pleural fluid
contained moderate numbers of extracellular fungal hyphae (Figure 2)
that were often surrounded by degenerate neutrophils and fewer
macrophages. The hyphae exhibited predominantly tapered ends with
occasional end branching. The hyphae were septated and the septations
varied in length () and minimal to mild variation of septae width ().
The hyphae exhibited acute branching. Given the difference of fungal
morphologies between lesions of the digit and chest, concern for a mixed
fungal infection was suspected and culture and PCR were recommended for
further evaluation.
Given the poor prognosis, the owner elected palliative care, and
euthanasia was performed the following day after respiratory signs
recrudesced. A necropsy was performed. During gross examination, liver,
kidney, lung, pleural and pericardial fluid, and nail bed samples were
submitted for fungal culture and mycologic assessment. The thoracic
cavity contained approximately 2 liters of serosanguineous fluid (Figure
2B). Affecting approximately 80%, the pulmonary pleura and mediastinum
were markedly thickened with multifocal to coalescing, white-tan, firm
plaques and nodules. The pericardium was diffusely and markedly
thickened with a pyogranulomatous inflammation and contained
approximately 110 ml of red serosanguineous fluid (Figures 2C and 3).
The epicardium was also multifocally thickened, rough, and irregular
with the same white to tan nodules (Figure 2C). Examination of the
abdomen showed multiple, fairly demarcated, white, firm nodules ranging
from 0.1 to 0.3 cm in diameter and affecting approximately 5% of the
renal cortices bilaterally. Examination of the right, distal forelimb
revealed markedly edematous, firm, red digits 3 and 4. An open 1.0 x 0.6
cm wound was noted on the medial aspect of the right front 3rd digit
with pink, purulent exudation. There was a small amount of tissue loss
around the nail bed of the right front 4th digit with a small amount of
yellow-white fluid (Figure 2A).
Significant histopathologic findings included severe,
fibrinonecrotizing, pyogranulomatous dermatitis with intralesional and
intravascular brown-pigmented septate fungal hyphae and conidia,
necrotizing vasculitis, and fibroplasia of the nail beds of digits 3 and
4 of the right forelimb. Similar severe, fibrinonecrotizing,
pyogranulomatous pneumonia, pleuritis, pericarditis, and nephritis with
intralesional fungal hyphae that exhibited different morphology from
hyphae seen on digits 3 and 4, fibroplasia, and serosanguineous effusion
were also noted (Figures 1 and 2). Fungal cultures were obtained from
samples taken from the visceral organs (lung, liver, and kidney) and
presumptively identified as Aspergillus terreus by
matrix-assisted laser desorption ionization time-of-flight (MALDI-ToF
MS). Another culture of a dematiaceous fungus was isolated from nail
beds of digits 3 and 4 of the right front limb and was identified by
MALDI-ToF MS as Curvularia lunata . A culture slant of the
presumptive Aspergillus terreus UTHSCSA DI20-341 isolate obtained
from the lung was submitted for species confirmation to the Fungus
Testing Laboratory at the University of Texas Health Science Center at
San Antonio (FTL).