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Small Animal Medicine: Exam 2 (Spring 2016) > L15: Fungal Disease Pt.2 (Specht) > Flashcards

L15: Fungal Disease Pt.2 (Specht) Flashcards

1
Q

Where is blasto found?

A
  • Mississippi, Missouri, and Ohio River valleys
  • Mid-atlantic states
  • Southern Canada
  • areas of high humidity/fog
  • sandy, acidic soils near H2O
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2
Q

Blasto trans. And animals affected

A

Transmission: inhalation +/- contamination of puncture wounds or open sores

Dogs: large breed, young, male

Cats: young males (roaming behavior)

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3
Q

Pathophys. Of Blasto

A
  • causes granulomatous to pyogranulomatous inflammatory response**
  • cell-mediated immunity
  • transforms to yeast in lungs –> hematogenous or lymphatic spread
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4
Q

CS of Blasto

A
  • resp/non-specific signs common: cough, dyspnea, exercise intolerance, anorexia, weight loss
  • ocular disease: anterior uveitis, endophthalmitis, optic neuritis
  • Skin dz: cutaneous/SC nodules +/- draining tracts
  • Misc: fever, lymphadenopathy, CNS signs, lameness, splenomegaly, depression
  • CATS may have above +/- GI dz, UT dz, pleural or abd. Effusion
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5
Q

Dx of Blasto

A
  • Definitive dx requires cytology, histo, or culture**
  • Serology: Ab only develop in some exposed animals (false negatives common). Ag testing better
  • thoracic rads abnormal 85% of the time
  • rads of bone lesions
  • MDB has no specific findings
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6
Q

CBC/Chem of Blasto

A

CBC: non-regenerative anemia, lymphopenia, neutrophilic leukocytosis (+/- left shift)

Chem: hypoalbuminemia and hyperglobulinemia +/- hypercalcemia

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7
Q

Radiographic findings with blasto

A

Thoracic:

  • diffuse, miliary to macro-nodular interstitial pulmonary pattern
  • single masses, alveolar patterns, pleural effusion, etc. possible

Bone lesions: usually lytic with periosteal reaction surrounding and soft tissue swelling (looks similar to OSA but less proliferative)

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8
Q

Cytology and histo of Blasto

A

Cytology:

  • concurrent granulomatous/pyogranulomatous inflammation
  • use sputum, cutaneous exudates, FNA of lesions, ocular fluid, etc.
  • may have false -

Histo:
concurrent granulomatous/pyogranulomatous inflammation with organisms observed in tissue samples

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9
Q

Tx of blasto

A
  • Itraconazole first choice if no CNS or ocular involvement
  • other choices: fluconazole, terbinafine, ketoconazole, amphotericin B
  • treat at least 60-90 days or continue at least 1-2 months past resolution or measurable signs**
  • median duration of tx = 8-9 months
  • tx is expensive
  • controversial if should used anti-inflammatory steroids at beginning of therapy to avoid severe inflammation from death of fungal organisms
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10
Q

Prognosis of Blasto

A
  • poor if CNS involved
  • guarded w/ severe pulmonary involvement
  • may have to remove eyes if in eyes
  • good otherwise w/ 80% cured
  • tx relapses w/ 2nd full course of anti-fungals (resistance uncommon)
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11
Q

Causative organism of Cryptococcosis

A

Cryptococcus neoformans

  • a dimorphic fungus
  • pathologic form = extra-cellular, thin-walled, narrow-budding yeast w/ very thick capsule
  • yeast in animal AND the environment*
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12
Q

Causative agent of Blastomycosis

A
  • Blastomyces dermatitidis, a dimorphic fungus that is a saprophyic mycelial spore-producing form in soil and yeast form in the body
  • pathologic form is extra-cellular yeast
  • yeast has broad-based budding with thick, refractile, double contoured wall
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13
Q

Distr. And transmission of Crypto**

A
  • worldwide, esp. In S. California and E. Australia
  • found in bird excrement
  • Trans: inhalation (nasal and pulmonary infection most common)
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14
Q

Most common systemic fungal disease in cats**

A

Crypto (usually

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15
Q

What age dogs more commonly get crypto?

A

1-7 years

Purebreds over represented

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16
Q

Pathophys. Of crypto

A
  • inhaled particles most often trapped in upper airway –> nasal disease –> hematogenous spread to extra-pulmonary sites
  • CNS may occur by direct extension across cribiform plate
  • cell-mediated immunity
  • granulomatous to pyogranulomatous inflammatory response with ineffective phagocytosis
  • not only opportunistic, but actively causes infection and avoids immune system**
  • don’t have to be immunocompromised to get it
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17
Q

Why is phagocytosis against crypto ineffective?

A

thick polysaccharide capsule inhibits multiple components of immune dz

18
Q

CS of crypto in CATS

A

Sneezing and nasal d/c (80%): uni or bilateral, serous to mucopurulent +/- blood tinged
-lesions extending from nares, facial deformity, or ulceration of nasal planum

Cutaneous or SC masses (40-50%)
Ocular inflammatory lesions
Non-specific: anorexia, lethargy
CNS signs
Misc. signs relating to inflammation and organisms in lung, LN, bone, kidney
19
Q

CS of Crypto in DOGS

A
  • nasal, CNS, and ocular manifestations most common
  • wt. loss, lethargy
  • skin, kidney can also be affected
20
Q

Differentials for severe nasal ulceration in dogs

A

Immune mediated dz
Crypto
Asper

21
Q

Dx of Crypto

A
  • serology is #1 test in cats (very good Se/Sp)
  • cytology (false - possible)
  • skull rads/CT/MRI: see increased ST in nasal cavity, nasal bone lysis and deformity, and/or contrast-enhancing mass lesions in CNS
  • histopath
  • culture (has sensitivity issues)
  • MDB non-specific
  • thoracic rads usually normal (can see hilar lymphadenopathy and/or diffuse to miliary interstital pulm. Pattern)
22
Q

CBC, UA abnormalities possible with Crypto that may aid in dx

A

CBC: monocytosis, non-regenerative anemia
UA: organisms may be present on sediment in dogs

23
Q

Tx of crypto

A
  • Itra = 1st choice if no CNS involvement
  • tx for 1-2 months past resolution of CS and neg. titers
  • mean tx time = 8.5 months
  • nasal and cutaneous dz responds better than ocular and CNS dz
  • tx CNS dz with amphotericin B, others
24
Q

Crypto vs. Blasto: which develops resistance to antifungals?

A

CRYPTO

-may need to switch antifungal in middle of tx, or do antifungal sensitivity testing

25
Q

Causative agent of histoplasmosis

A

Histoplasma capsulatum

  • dimorphic fungus that has saprophytic mycelial form in env. and yeast form in body
  • small INTRA-cellular yeast with thick wall and broad-based budding
26
Q

Distr. And transmission of Histo

A
  • around mississsippi, missouri, and ohio river valleys, and southwest and mid-atlantic states
  • concentrated in bird/bat poop
  • trans: inhalation (or ingestion?)
  • more common in young male sporting dogs, and young cats
27
Q

Pathophys. Of histo

A
  • spores transform to yeast at body temp
  • yeast engulfed by mononuclear phagocytes and undergo further replication by budding –> hematogenous or lymphatic spread
  • cell mediated immunity usually clears infection unless there is high infective dose or immune deficiency
  • granulomatous inflammation develops in persistently infected organs
28
Q

CS of histo

A

DOGS:
-anorexia, wt. loss, fever, cough, dyspnea, diarrhea (LI most common)
+/- polyarthritis, PLN, chorioretinitis, CNS signs, skin lesions

CATS:
-similar, but with profound weight loss

29
Q

Dx of Histo

A
  • cytology for definitive dx* (shows granulomatous or pyogranulomatous inflammation, intracellular organism)
  • MDB: typical inflammatory response
  • serology unreliable
  • thoracic rads: 85% have diffuse, miliary or nodular interstitial pattern, hilar lymphadenopathy
  • Rads of lytic bone lesions
  • Abd. Imaging
30
Q

CBC/Chem of histo patient

A 
(Usually no specific signs)
CBC: 
-non-regenerative anemia
-intracellular organisms in monos, neuts, eos
-thrombocytopenia
-cats may be pancytopenic

Chem:
-hypoalbuminemia or inc. LIV enzymes

LIV fx tests may be abnormal

31
Q

Findings on abdominal imaging of histo patient

A
  • dec. detail due to poor body condition
  • hepato/splenomegaly; effusion
  • thickened/irregular GI wall w/ contrast
  • lymphadenomegaly/opathy
32
Q

Tx of histo

A
  • Itraconazole 1st choice if no CNS/ocular involvement
  • others: amphotericin B, fluconazole, terbinafine, ketoconazole
  • tx >60-90 days or at least 1-2 mo. Past resolution of signs
  • if relapses, tx with 2nd full course of anti-fungals
  • anti-fungal resistance uncommon
  • prognosis excellent w/ only pulmonary involvement, but guarded to fair with dissemination
33
Q

Causative agent of Coccidioidomycosis

A

Coccidioides immitis:

  • dimorphic fungus with mycelial form and pathologic spherule form
  • spherule is large, round, double-walled, and contains multiple endospores
34
Q

Distr. and trans. of coccidio

A
  • regions with dry, warm climates and sandy soil
  • CA, NM, AZ, UT, NV, and southwest TX
  • number of cases increases after high rainfall years
  • trans: inhalation
  • common environmental exposure - it’s everywhere!
  • young male dogs overrepresented
35
Q

Pathophys. Of coccidio

A

1) phagocytosis and increased CO2 –> arthroconidia transform to spherules
2) endospores divide w/n spherule (and a protected from immune system)
3) endospores released into tissues and are phagocytized or (if immune system overwhelmed) disseminates to mediastinal/tracheobronchial LN, bones, eyes, heart, pericardium, testes, brain, spinal cord, visceral organs
4) neutrophilic inflammation
5) monocyte, lymphocyte, and plasma cell infiltration
6) resp. Signs develop w/n 1-3 wks, disseminated dz develops w/n 4 months of exposure

36
Q

CS of coccidio in DOGS

A

DOGS:

  • cough, weakness, lethargy, anorexia, wt. loss, fever
  • lameness w/ painful swollen bone lesions
  • localized lymphadenopathy, ocular and skin lesions
  • skin lesions often overlay bone lesions
  • diarrhea, non-specific signs
37
Q

CS of coccidio in CATS

A
  • Skin lesions even w/o underlying bone lesions

- fever, anorexia, wt. loss

38
Q

Dx of coccidio

A
  • Cytology: #1 diagnostic. Done on sputum, lung washes, exudates, or FNA. False - possible. See concurrent inflammation
  • MDB non-specific inflammatory
  • Serology: Ab tests only
  • Thoracic rads: hilar lymphadenopathy, diffuse interstitial, pleural effusion
  • Bone lesion rads: more proliferative than lytic
  • Histo/culture: look for gigantic structures
39
Q

CBC/Chem/UA changes of coccidio patient

A

CBC: normocytic, normochromic non-regen. Anemia, leukocytosis or leucopenia, and/or monocytosis

Chem: hyperglobulinemia (polyclonal), hypoalbuminemia, and/or renal azotemia

UA: proteinuria

40
Q

Challenges of serology for coccidio (S.O.)

A
  • only Ab tests are Se and Sp enough
  • fale negs can occur in early infection, cutaneous infection, chronic infection, or rapidly progressing acute infection
  • false positives can occur due to immune complexes or bacterial contaminants
  • can cross react with H. Capsulatum and B. Dermatitidis
41
Q

Tx of coccidio

A
  • itra 1st choice
  • treat for at least 1-2 months past resolution of measurable signs
  • typical duration of tx = 6-12 mos.
  • prognosis depends on degree of dissemination
  • bone infections often incurable
  • overall recovery rate ~60%
  • titers can persist months-years after clinical resolution

Small Animal Medicine: Exam 2 (Spring 2016) (13 decks)

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