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Flashcards in Infectious Dz - Fungal Deck (115)
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1

Where is blastomycosis distributed?

On the eastern half of the US, especially in the Mississippi, Ohio, and Saint-Lawrence River values

2

What type of fungi is Blastomyces dermatitidis?

Dimorphic

3

In what form is Blastomyces dermatitidis in the host?

yeast

4

In what form does Blastomyces dermatitidis exist in the soil as?

a fungal hyphae

5

What form of Blastomyces dermatitidis is infective?

only the fungal form

6

By what route does Blastomyces dermatitidis infection occur?

Inhalation (most common) and direct inoculation

7

What is the incubation time of Blastomyces dermatitidis?

Long incubation - 1-3 months

8

Where does Blastomyces dermatitidis propagate and how does it get there?

Via hematogenous spread it propagates to the skin, eyes, lymph nodes, bone, and CNS

9

What is the 'poster dog' for blastomycosis?

Young (2-4 years) and large hunting breeds

10

What are the risk factors for blastomycosis in dogs?

living near water and proximity to excavated or disturbed soil

11

Is blastomycosis found in cats?

It is very rare

12

What are the PE findings associated with blastomycosis?

Non-specific signs of fever, anorexia, and weight loss
Respiratory signs are common
Ocular manifestations - uveitis
Granulomas
Draining lesions
Lameness

13

What will you find on CBC in a patient with blastomycosis? Chemistry?

CBC - inflammatory leukogram
Chemistry (from most to least common)- Low albumin, high globulin, and hypercalcemia

14

What will you find on cytology in patients with blastomycosis?

Broad-based budding yeast and pyogranulomatous inflammation with concurrent presence of neutrophils with activated macrophages, lymphocytes, and plasma cels

15

What will you see on rads in a patient with Blastomycosis?

Variable lung pattern - classically diffuse miliary to nodular
Tracheobronchial enlargement in 25% of cases
Osteolysis with periosteal reaction in bones

16

What does serology detect for in a suspected Blasto case?

antibodies

17

What is the gold standard diagnostic test for blastomycosis?

Galactomannan cell wall test

18

What is the Galactomannan cell wall test?

It is an antigen test with very high sensitivity. Urine is more sensitive than serum
There is some cross-reactivity with Histoplasma so a cytology will need to be done to confirm

19

What diagnostic test is not recommended for blastomycosis?

Culture - because it reverts to the fungal form and there is a potential danger for lab personnel

20

How is blastomycosis treated?

Triazoles - Itraconazole is the drug of choice but Fluconazole may have similar efficacy and Fluconazole and voriconazole achieve better CNS/ocular penetration than itraconazole

Amphotericin B may be warranted in more aggressive/extensive disease

Glucocorticoids for decreasing pulmonary inflammation associated with the fungal die off - avoid high doses

21

When is surgery indicate to treat blastomycosis?

If there is severe panuveitis that requires enucleation

22

Is blastomycosis treatment long or short term? When do you know when to stop treatment?

Long term
Use Galactomannan assay results to determine presence of fungi

23

What is the prognosis of blastomycosis?

Variable cure rates - 50-75%
Relapses are common within 2 years

24

What are the negative prognostic factors of blastomycosis?

CNS involvement, severity of lung disease, and high band count on CBC

25

What are the differentials to be considered with blastomycosis?

Neoplasia, other systemic mycoses, and systemic protozoal infections

26

Where is histoplasmosis distributed?

Similar to blasto - north of the equator and in the eastern US in the Ohio and Mississippi river valleys

27

What causes histoplasmosis?

Histoplasma capsulatum

28

What type of fungus is histoplasmosis?

Dimorphic

29

How does histoplasmosis infection occur?

It is inhaled or ingested by the host from avian and/or bat guano

30

Where does Histoplasma capsulatum replicate/dissemiate?

In macrophages

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