Lecture 15: Mycology 2

Question 1

What are the 3 most common systemic mycoses in the USA?

Answer 1

-Blastomycosis
-Histoplasmosis
-Coccidioidomycosis

Question 2

Systemic fungal pathogens are primarily what type of pathogen?

Answer 2

True pathogens- that don’t require an immunocompromised host

Question 3

Systemic fungal infections for Blastomycosis can dissipate to what organs?

Answer 3

-skin
-bone
-genitourinary tract

Question 4

Systemic fungal infections for Histoplasmosis can dissipate to what organs?

Answer 4

-liver
-spleen
-lymph nodes
-bone marrow

Question 5

Systemic fungal infections for Coccidioidomycosis can dissipate to what organs?

Answer 5

-CNS
-bone

Question 6

Systemic fungal infections for Paracoccidioidomycosis can dissipate to what organs?

Answer 6

Mucosa of the mouth and nose

Question 7

All systemic mycoses begin as

Answer 7

Pulmonary infections
-after spore production from the fungi found in the soil and feces of birds and bats. The spores become airborne.
When inhaled, spores cause a primary pulmonary infection

Question 8

Blastomycosis
-transmission
-found in

Answer 8

-Geophilic transmission!- Canadian provinces that border the Great Lakes. Endemic to central & southeast USA
-Found in soil and decaying vegetation (fertilizers & dead animals)

Dead Animals= birds and bats???

Question 9

Blastomycosis
Symptoms

Answer 9

-asymptomatic
-primary pulmonary blastomycosis
acute pulmonary disease = pleuritic chest pain, fever, chills, resembles bacterial pneumonia
chronic pneumonia = hemoptysis, fatigue, night sweats, resembles TB or lung cancer

Question 10

Blastomycosis Dissemination

Answer 10

SKIN, BONE,GENITOURINARY TRACT
-cutaneous blastomycosis (begin as subcutaneous nodules that ulcerate) (results in irreversible wart-like scars)
-osteoarticular blastomycosis
-brain abscess = Immunocompromised
-genitourinary = men (painful urination, prostate affected)

Question 11

Pathogenesis for blastomycosis

Answer 11

-dimorphic fungi
-conidia are phagocytosed but if they escape they transform to yeasts (greater-resistance)
being a yeast allows for dissemination via blood and lymphatic circulations an effective TH1 will prevent this dissemination but if TH1 lowers and TH2 increases dissemination will occur.

Question 12

Diagnosis Blastomycosis
Treating blastomycosis mild to severe

Answer 12

-demonstrate thick-walled yeast with broad based attachment … confirm with culture

-treatment
Mild to moderate cases= itraconazole
Severe/disseminated cases= amphotericin B

Question 13

Histoplasmosis
-transmission
-found in

Answer 13

Geophilic transmission: highly endemic to the Ohio-Mississippi river
Found in bird and bat remaining

Question 14

Histoplasmosis symptoms
-acute vs. chronic

Answer 14

Acute pulmonary histoplasmosis
-asymptomatic
-flu-like symptoms
-self-limiting
chronic pulmonary histoplasmosis
-occurs in patients with underlying pulmonary disease (resembles TB, night sweats, fever)

Question 15

Dissemination of Histoplasmosis
-acute vs. subacute

Answer 15

occurs more often in immunocompromised and CHILDREN
-acute presentation =
respiratory failure, shock, coagulopathy and multi-organ failure. fatal days to weeks (untreated)
-subacute = slower disease course
hepatosplenomegaly, thrombocytopenia, fever, weight loss are common. Can include meningitis, ulcers of oral mucosa, GI ulcers w/ bleeding. fatal days to months if left untreated

Question 16

Histoplasmosis oral lesions

Answer 16

-tongue
-palate
-buccal mucosa

Question 17

Pathogenesis Histoplasmosis

Answer 17

-dimorphic
-yeast live in and spread inside by a phagocyte. (The WBC does not inhibit this growth)
-cell-mediated is key (granuloma to contain the infection) yeast can escape and cause a relapse of diseases

Question 18

Diagnosis Histoplasmosis

Answer 18

1st Staining: bone marrow, bronchial lávate fluid, sputum
2nd culture: ONLY WAY TO DEFINITIVELY DIAGNOSE

Question 19

Treatment for histoplasmosis

Answer 19

Mild- supportive care
Moderate to severe pulmonary- Amphotericin B, then Itraconazole
Chronic pulmonary - Itraconazole
Disseminated histoplasmosis- Amphotericin B, then itraconazole (AIDS patients may require lifelong itraconazole)

VS. BLASTOMYCOSIS
Mild to moderate: itraconazole
Severe & disseminated patients: Amphotericin B

Question 20

Coccidioidomycosis
-transmission
-found in

Answer 20

-geophilic transmission
-most common in late/summer/early fall when soil dries… during dry seasons

Question 21

Coccidioidomycosis
-primary Coccidioidomycosis
-secondary Coccidioidomycosis

Answer 21

Primary
-most common
-asymptomatic in most cases
-Flu-like symptoms (fever, chills, night sweats, cough…)

Secondary
-chronic
-nodules, cavitary disease, or progressive pulmonary disease

Question 22

Coccidioidomycosis dissemination and its risk factors

Answer 22

1% of secondary Coccidioidomycosis patients
Risk factors
-males
-3rd trimester pregoooo
-mortality exceeds 90% w/o treatment
-50% of dissemination ends in meningitis (however it can be multi-organ)

Question 23

Pathogenesis for coccidioides

Answer 23

dimorphic fungus
-begins w/ inhalation of arthroconidia
-in bronchioles… form spherules
-spherules rupture and release endospore
-phagocytosis of endospore =acute pulmonary inflammation
If infection is not cleared = chronic inflammation (granuloma) “protective immunity follows infection”

Question 24

Diagnosis for Coccidioidomycosis

Answer 24

-Clincial specimen (preferred)
-morphological differences in spherules allow differentiation b/w the two pathogens.
-IgM and IgG = ELISA

Question 25

Treatment for coccidioidomycosis
-patients w/ no risk factors for dissemination
-patients w/ risk factors for dissemination
-secondary Coccidioidomycosis

Answer 25

W/o risk:
-asymptomatic air self-limiting
W/ risk
-Amphotericin B, then Intraconzole
secondary Coccidioidomycosis
-chronic cavitary disease = itraconazole
-meningeal = fluconazole