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Micro Exam 3 > Primary Systemic Mycoses > Flashcards

Primary Systemic Mycoses Flashcards

1
Q

3 categories of primary systemic mycosis?

A

1) coccidioidomycosis
2) histoplasmosis
3) blastomycosis

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2
Q

What do all primary systemic mycoses have in common?

A
  • Generalized throughout the body and typically subclinical
  • Restricted to a particular geographical area
  • Initiated in the LUNGS
  • NOT transmissible
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3
Q

Geographical area for coccidioidomycosis?

A

Southwest- semiarid regions

aka. San Joaquin Fever, Valley Fever

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4
Q

What was inhaled to cause coccidioidomycosis?

A

Coccidioides immitis spores (from dried up soil/dust)

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5
Q

Describe coccidioides immitis dimorphism

A 
Cool temps (25C) - branching, septate hyphae --> arthrospores
Body temp - spherules containing ENDOSPORES in tissues
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6
Q

Two phases of coccidioides immitis: one in soil one in infected tissues

A

1) Mycelial arthrospore-soil:
Fungi live in dry desert conditions for years –> grow during rainy season (not infectious) –> hyphae develop arthropsores when dry summer months come along (disseminate as arthrocondia) –> become airborne
2) Spherule endospore-infected tissues:
Inhaled arthrospore turns into thick-walled spherule containing endospores–> spherules eventually open and release –> proliferation of infxn.

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7
Q

Primary Pulmonary Coccidioidomycosis

A
  • 60% asymptomatic
  • 95% recover from symptomatic (mild flu-like symptoms starting roughly 2 wks. after inhalation)
  • 5-8% progress to chronic (cavities and nodules in lungs)- due to failed immune response
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8
Q

Disseminated Coccidioidomycosis (mostly in immunocompromised)

A
  • Less than 1% affected –> rapid, and fatal
  • Spread beyond lungs –> lymph –> blood spread
  • Present with dramatic sweats, dyspnea at rest, fever, weight loss
  • Often skin, bones, joints, and CNS (meningitis)
  • Can take weeks to 2 years
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9
Q

Diagnosis for Coccidioidomycosis

A

Micro: Spherules in sputum, exudate, tissues in KOH
Serology: Coccidioidin Ag to detect antibody to mycelial-phase proteins; serum IgM Ab with primary infections; IgG later
Elevated IgG serum Ab is marker of disseminated (extrapulmonary)

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10
Q

Treatment for Coccidioidomycosis

A

Fluconazole, Itraconazole, or Amph B

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11
Q

What is the most prevalent mycotic infection in humans and animals?

A

Histoplasmosis

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12
Q

What are the two varieties of histoplasmosis causing agents?

A

1) Histo. Capsulatum capsulatum

2) Histo. Capsulatum duboisii

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13
Q

Dimorphism of Histo

A

Ambient/Cool temps (25C) - branching, septate hyphae –> microcondia and TUBERCULATE (round) macrocondia
Body temp- small, narrow-based, ovoid, budding yeast

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14
Q

Where is Histo normally found?

A

Soils contaminated with bird dung- chicken coops, roosts, caves, etc.

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15
Q

Who is at high risk for Histo infection?

A
  • Construction; bulldozing decaying buildings
  • Smokers
  • Children
  • Immunocompromised
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16
Q

Acute forms of histoplasmosis

A

1) Acute asymptomatic pulmonary

2) Acute symptomatic pulmonary: Chest pain while inhaling, fever, cough, chills

17
Q

Chronic Pulmonary Histoplasmosis

A
  • Fever- may resemble symptoms of pulmonary TB (cough up blood)
  • Excessive sweating
  • Shortness of breath
  • Cough
  • Chest Pain
18
Q

Disseminated Histoplasmosis

A
  • Mouth sores
  • Skin Lesions
  • Headache
  • Fever

Other: can have joint pain, rashes, ERYTHEMA NODOSUM

19
Q

What is the infectious/inhaled version of Histo?

A

Microconidia in soil containing bird droppings

20
Q

Pathogenesis of Histoplasmosis

A
  • 90% inhibited through CMI
    Microconidia is inhaled –> develop into yeast and replicate in alveolar MQ –> acute pulm. histo (self-limiting; some nodules heal with calcification) –> chronic pulm. histo (especially in men with emphysema)
    **After lung development can take disseminating route to reticuloendothelial tissues and become granulomatous –>DEATH
21
Q

Geographical area for Histoplasmosis

A

Central and eastern states, Ohio River Valley, and Mississippi River Valley… Indiana area-ish. and more south.

22
Q

Because yeast form survive and thrive in MQ like TB, infected individuals will have a similar response in a Histo skin test.

A

FYI

23
Q

What percent of the population would likely test positive for Histo ‘round these parts?

A

90% COMFORTING

24
Q

Diagnosing Histoplasmosis

A
  • Presence of fungus in sputum, lung tissue, blood, CSF, BM
  • Ag test: Capsular Ag in blood, urine, CSF
  • X-rays show lung abnormalities- hilar calcifications
25
Q

Histoplasmosis Treatment

A

Itraconazole/Amph B

26
Q

What is the cause of Blastomycosis?

A

Blastomyces dermatitidis

27
Q

What immune defect can Blasto cause?

A

Chronic granulmatous disease

28
Q

Dimorphism of Blastomyces dermatitidis

A

Cold- septate, UNBRANCHED, short conidiophores (unicellular)

Heat- Budding yeast cells- double contoured wall with a single bud on wide base

29
Q

What percent of Blastomyces dermatitidis infections are asymptomatic?

A

50%

30
Q

Acute Pulmonary mimic bacterial pneumonia (TB)

A
  • Dry cough, fever –> weight loss, chest pain, persistent cough with thick sputum
    • Muscle aches, night sweats, coughing up blood
  • Incubation period: 3 weeks to several months
31
Q

Infection can spread by blood to skin, bone, etc.

A
  • SKIN infection appears as growing raised, bumpy lesions with ulcerating centers on distal extremities,
  • Can spread to bones, prostate gland, testes, kidneys (rare)
32
Q

What is the infectious form of Blastomyces dermatitidis?

A

Aerosolized conidial mold

33
Q

Pathogenesis of Blastomycosis

A

Inhaled as conidia –> transform into yeast –> multiply and may disseminate through blood –> inflammatory responses (neutrophils, followed by MQ) –> GRANULOMA

34
Q

Geographical area for Blastomycosis

A

Similar to Histo: South central states along Mississippi and Ohio River. Reaches further north. Sorta looks like bunny ears around Great Lakes. Great Lakes is a buzz … phrase.

35
Q

Outbreak causing activities:

A

Recreational activities around river banks, collecting wood, being around organic debris/vegetation

36
Q

Diagnosing Blastomycosis

A
  • Look in sputum, pus, tissue exudates, urine, biopsies
  • Thick-walled yeast cells- barely attached buds seen in microscope
  • 2 weeks to culture
37
Q

Treatment Blastomycosis

A

Itraconazole, Fluconazole, Amph B (more serious)

38
Q

It appears as though the treatment for Primary Mycoses is/are:

A

Itraconazole is always a safe bet and Amph B for more serious. Sometime Fluconazole is thrown in.

Micro Exam 3 (11 decks)

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