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Microbiology Exam 2 > 31 - Fungal Infections of the Respiratory Tract > Flashcards

31 - Fungal Infections of the Respiratory Tract Flashcards

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1
Q

Review: Fungi which can grow as both yeast and mold are know as?

A

Dimorphic

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2
Q

Review: An India ink test is used to aid in the identification of?

A

Cryptococcus neoformans

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3
Q

Review: - What looks like long strings of fungi with septations in the string?

A

Septate hyphae

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4
Q

What are zygomycoses (or mucormycosis)?

A

The type of diseases that are caused by a group of uncommon but potentially fatal fungi belonging to the class Zygomycetes

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5
Q

Where do we find zygomycetes in the enviroment?

A

Soil, vegetation and food (fruits and bread)

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6
Q

What are predisposing factors to contracting a zygomycoses (or mucormycosis) infection?

A
  • Immunosuppression***
  • Diabetes
  • Burn patients (no protective skin/innate immunity
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7
Q

How common are (or mucormycosis) infections in healthy individuals?

A

RARE

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8
Q

What are three types of zygomycetes?

A

Rhizopus
Absidia
Mucor

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9
Q

What is the common appearance of these zygomycetes?

A

Non-septate hyphae

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10
Q

What is the most common form of zygomycosis?

A

Rhinocerebral zygomycosis

Over 50% of cases

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11
Q

Which population is most likely to contract Rhinocerebral zygomycosis?

A

Diabetics *** :(

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12
Q

Where does the infection typically originate?

A

Sinuses - by inhalation of spores

Watch for Shannon getting a sinus infection

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13
Q

Where can this sinus infection spread to?

A

Extends to neighboring tissues (nose, adjacent sinuses, the hard palate, eye, and brain)

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14
Q

What does progression to the brain cause?

A

Progression to the brain results in altered mental status, coma and death

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15
Q

What individuals would tend to have a zygomycotic infection in the lungs, skin or GI tract?

A

Immunosuppressed or burn patients

  • Skin (traumatic inoculation)
  • GI (neonates and premature infants)
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16
Q

How do you diagnose zygomycoses?

A
  • Microscopic observation of hyphal elements in clinical material (sputum, etc)
  • Culture confirmation
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17
Q

What would you see in a microscopic observation of zygomycoses?

A
  • No septations
  • Very wide, broad hyphae
  • Branching at 90 degrees
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18
Q

How do you treat zygomycoses?

A

Amphotericin B

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19
Q

What is Candidiasis?

A

A yeast infection that is caused by a yeast in the genus family Candida, MOST COMMONLY candida albicans***

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20
Q

Is candida albicans considered normal flora?

A

Yes, on the skin, mucus membranes and GI tract it is

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21
Q

What is the difference between the form that causes disease and the form that is normal flora?

A

Yeast form = normal flora

Hyphal form = disease causer***

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22
Q

What do we call oral candidiasis?

A

THrush

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23
Q

Who is at risk for developing thrush?

A
  • Infants
  • Adults on steroids, antibiotics, etc.
  • AIDS patients
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24
Q

What is the clinical presentation of thrush?

A
  • White patches on buccal mucosa, throat, tongue, and gums
  • Scrape off white to see red lesions
  • Find yeast and hyphal forms of c. albicans in white stuff
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25
Q

How do you diagnose thrush?

A
  • Clinical observation

- Culture is not necessarily needed

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26
Q

How do you treat thrush?

A

Oral formulations (mouth washes or lozenges) of nystatin and azole compounds

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27
Q

What are systemic mycoses?

A

Fungal infections that begin with a pulmonary infection by inhaling fungal elemetns, but can cause systemic infections

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28
Q

What are the five systemic mycoses?

A 
1 - Histoplasma capsulatum 
2 - Blastomyces dermatitidis
3 - Paracoccidioides brasiliensis
4 - Coccidioides immitis
5 - Cryptococcus neoformans
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29
Q

What is important about coccidioides imitis?

A

Dimorphic fungi

  • Mold in environment
  • Yeast in the body
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30
Q

Would you expect to see hyphe in the body of someone infected with coccidiodes imitis?

A

NO ***

- It is not a mold in the body, so no hyphe

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31
Q

What is important abotu cryptococcus neoformans?

A
  • Encapsulated yeast in the environment and body

- Found worldwide

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32
Q

What is histoplasmosis?

A

A fungal infection found in distinct parts of North and Central America

AKA cave dwellers, Darling’s ***

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33
Q

Where have we seen endemics in the US of histoplasmosis?

A

Mississippi river and ohio river valleys

50-80% of the population of this area are skin test positive

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34
Q

What is histoplasmosis cased by?

A

Histoplasma capsulatum

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35
Q

Where do we find Histoplasma capsulatum?

A
  • Soil in humid climates
  • Bird/bat dropings
  • Chicken coups
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36
Q

How do you aquire histoplasmosis?

A

Inhalation of microcondria from environment

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37
Q

What do these fungi look like under a microscope?

A

Macroconidia of H. capsulatum have a characteristic tuberculate (round bump) appearance

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38
Q

What are the symptoms of histoplasmosis?

A

95% of exposed/infected individuals appear to be asymptomatic.

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39
Q

What is the disease mechanism of histoplasmosis?

A

Inhaled fungal spores are phagocytosed by pulmonary macrophages and convert to their yeast form.

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40
Q

What happens once the yeast form is in the body?

A

The organism can replicate within macrophages and spread through the lymphatic and reticuloendothelial system

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41
Q

What is pulmonary histoplasmosis?

A
  • A mild flu-like illness with a dry cough, fever, and fatigue
  • Develops several weeks after exposure and improves within 2 to 3 weeks
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42
Q

Do most cases need an antifungal?

A

No - resolve on their own from CMI

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43
Q

What clincial sign is common?

A

Calcification of pulmonary lesions is common

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44
Q

What can occur in severe infections?

A

Pulmonary infiltrate and chest pain are more common in severe infections.

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45
Q

What happens when the acute infection becomes a disseminated disease?

A

Two things could happen:

  • Could be a severe accute illness
  • Could be a chronic and slowly debilatating illness
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46
Q

What are symptoms of disseminated histoplasmosis?

A

Individuals experience fever, night sweats, anorexia, weight loss, and fatigue in addition to respiratory symptoms

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47
Q

Where can the infection spread to?

A

Liver, spleen, lymph nodes

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48
Q

How do you diagnose histoplasmosis?

A

Direct observation of organisms (yeast form) in tissues or clinical samples (sputum)

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49
Q

Why is this hard to detect?

A

Detection of yeast forms in tissue or sputum samples is difficult due to their small size and lack of distinctive morphology.

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50
Q

How do you treat histoplasmosis

A

Amphotericin B

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51
Q

What do you do if your pateint has AIDS and this infection?

A

Often require lifelong suppressive therapy to prevent relapse frequently with azoles (less toxic)

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52
Q

What is Blastomycosis?

A

An endemic in the Ohio and Mississippi river valley and to a lesser extent the Missouri and Arkansas river basins

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53
Q

What fungi causes blastomycosis?

A

Blastomyces dermatitidis

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54
Q

What type of fungus is Blastomyces dermatitidis?

A

A dimorphic fungi

Environment = mold
Body = yeast
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55
Q

What does the yeast from a body sample look like?

A

Larger size and very thick cell walls

56
Q

What is the primary disease with blastomycosis?

A

Primarily a pulmonary disease, with the potential to disseminate causing ulcerative lesions of the skin, bone, and urogenital tract.

57
Q

How do you contract blastomycosis?

A

Acquired through inhalation of spores from the environment

58
Q

Are most cases symptomatic?

A

No, most are asymptomatic

59
Q

There are three types of clinical cases of blastomycosis. WHat are they?

A
  • Acute
  • Chronic
  • Dissemminated
60
Q

What is acute blastomycosis?

A

Acute: cough, fever, chills, arthralgia, myalgia, sputum production*

61
Q

What might acute present like?

A

Bacterial pneumonia (chest pain, sputum production)

62
Q

What is chronic pulmonary blastomycosis?

A

cough, fever, night sweats, weight loss, sputum production (mimics TB)

Typically resolves without intervention

63
Q

What is seen in the disseminated disease of blastomycosis?

A

Disseminated disease

  • Skin lesion - ulcerative and disfiguring (painless)
  • Bone infection - necrosis and granuloma formation
  • Prostate appears to be especially prone to infection.
64
Q

How do you diagnose blastomycosis?

A
  • Observation of distinct yeast forms in sputum or biopsy material
  • Cultivation may take 2-3 weeks
65
Q

What do you treat blastomycosis with?

A

If you treat at all…

  • Amphotericin B
  • Azole
66
Q

What is paracoccidiomycosis?

A

A disease limited to the tropical regions of S and central America and mostly MEN

67
Q

What causes paracoccidiomycosis?

A

Paracoccidioides brasiliensis (brazil = south and central america = easy to remember)

68
Q

What type of fungi is Paracoccidioides brasiliensi?

A

DImorphic

69
Q

Why is it more common in men?

A

Inhibited by estrogen

70
Q

How will Paracoccidioidomycosis present?

A
  • Most infections are asymptomatic.
  • Pulmonary infection is similar to histoplasmosis and blastomycosis.
  • Disseminated disease presents as chronic cutaneous and mucocutaneous ulcers
71
Q

How do you diagnose?

A

Direct observation, cultivation, and serology

72
Q

What will you see in teh microscope of a patient with paracoccidiodomycosis?

A

Distinctive forms observed under microscope:

  • Mickey mouse ears
  • Ships wheel
73
Q

What is coccidioidomycosis?

A

A common fungi infection seen in the US, mostly in California and Arizona due to the drought-rain-drought pattern

74
Q

What does the drought-rain-drought pattern contribute?

A

Spores in dry, germinate in rain, drought makes more spores form

75
Q

How do they spread?

A

large numbers of fungal elements present in blowing dust

76
Q

What type of fungi is coccidioidomycosis?

A

Dimorphic

77
Q

Following inhalation the fungus converts into a ________

A

spherule ***

78
Q

What is a spherule?

A
  • A multinucleated structure

- Produces hundreds of single nucleated spores

79
Q

What form do spores convert to in the enviroment?

A

Mold

80
Q

What form do spores convert to in the body

A

New spherules

81
Q

What percent of coccidioidomycosis patients are asymptomatic?

A

60%

82
Q

What is the clinical presentation of coccidioidomycosis if the patient develops symptoms?

A

Pulmonary disease
- Mild to moderate influenza like syndrome
fever, cough, night sweats, malaise and chest pain

  • Symptoms develop 1 to 3 weeks after infection
83
Q

Does this spontaneously resolve?

A

Yes - Most individuals spontaneously resolve the infection in 2 to 3 weeks

84
Q

What happens if it becomes a progressive chronic pulmonary disease?

A

Progressive chronic pulmonary disease which may result in cavity formation and take years to resolve

85
Q

How commo is a dissemiated disease from coccidiodomycosis?

A

RARE

86
Q

When does it typically develop if it does?

A

Within one year of infection

87
Q

What will the disseminated disease infect?

A

Bones, joins, CNS

88
Q

What can this lead to in the CNS?

A

Coccidial meningitis

89
Q

What do you see in coccidial meningitis?

A

develops slowly with increasing headache, fever, stiff neck, and other neurological signs. If untreated, the disease is frequently fatal

90
Q

How do you diagnose coccidiodomycosis?

A

Direct observation
- distinct spherule forms in sputum or biopsy**

Cultivation

Serology

91
Q

How do you treatcoccidiodomycosis?

A
  • Azole

- Amphotericin B (meningitis and disseminated disease)

92
Q

What is cryptococcosis?

A

A fungal infection from Cryptococcus neoformans ***

93
Q

What is the leading form of fungal meningitis?

A

Cryptococcal meningitis is the leading form of fungal meningitis. **

94
Q

Is Cryptococcus neoformans a dimorphic fungi?

A

NOOOOOO***

95
Q

What is Cryptococcus neoformans in terms of fungal form?

A

An encapsulated yeast

96
Q

Where can you find Cryptococcus neoformans

in the environemtn?

A

Bird droppings, contaminated soil ***

97
Q

What is the primary disease we see with Cryptococcus neoformans?

A

Pulmonary disease

98
Q

How does a patient with a Cryptococcus neoformans pulmonary disease present?

A
  • asymptomatic or a mild, spontaneously resolving, influenza like illness
  • little sputum production
  • little damage to the lung (granuloma or cavitation
99
Q

What is the disseminated disease of crytococcosis?

A

Sink and bone lesions

100
Q

How does cryptococcosis meningitis present?

A

Meningitis:

  • Is the most common recognized form of cryptococcal infection
  • Develops slowly
  • Intermittent bouts of headache, irritability, dizziness, and other CNS findings
  • Symptoms may present over weeks or months
101
Q

What group is at increased risk?

A

AIDS/immunosuppressed

102
Q

How do you diagnose crytococcosis?

A

India ink stain

103
Q

How do you treat cryptococcosis meningitis?

A
  • Long term treatment (6-10 weeks) with a combination of Amphotericin B and 5-fluorcytosine or fluconazole.
  • Relapse in AIDS patients is common and may require suppressive therapy.
104
Q

Review: how will blastomycosis appear?

A

Broad-based budding yeast

105
Q

Review: how will coccidiodomycosis appear?

A

Spherules containing endospores

106
Q

Review: how will histoplasmosis appear?

A

Intracellular budding yeast

107
Q

Review: how will paracoccidiodomycoses appear?

A

Large multiply budding yeast

108
Q

What is Pneumocystis jiroveci (carinii)?

A

A fungi that leads to a highly lethal form of pneumonia

PCP: Pneumocystis carinii pneumonia

109
Q

When populations do we see this in?

A

AIDS/immunocompromised

110
Q

What percentage of AIDS patients will suffer from this

A

80%

111
Q

What percent die from it?

A

30-50%

112
Q

What type of organism is Pneumocystis jiroveci?

A

We don’t know a lot about it…

  • Single celled eukaryotic organism
  • Phylogenetically related to fungi
  • Some cellular and metabolic processes similar to protozoa
  • The organism is thought to exist in nature and in animals
113
Q

How are individuals infected with PCP?

A

Inhalation of cysts

114
Q

Will PCP ever be asymptomatic?

A

Yes, in healthy individuals

115
Q

If PCP is symptomatic, how will it present?

A

Dyspnea, nonproductive cough, and fever

116
Q

If the patient progresses, what will we see?

A
  • Patient develops interstitial pneumonitis with cellular infiltrate
  • Weakness, tachypnea (labored breathing), and cyanosis
  • Death results from asphyxiation
117
Q

How do you diagnose PCP?

A

Not easy… You will need to know what you are looking for and use a special staining technique

118
Q

How do you treat PCP?

A

Trimethoprim-sulfamethoxazole
(to interfere with the folate synthesis pathway of the organism)

In AIDS…
- Prophylaxis and suppressive therapy

119
Q

What is aspergillosis?

A

A fungal infection caused by A. fumigatus or A. flavus

120
Q

How pathogenic is aspergillosis?

A

Aspergillus is rarely pathogenic in individual with normal immune status

121
Q

What types of clinical diseases to we see?

A
  • Primarily a pulmonary infection

- Can disseminate to a wide range of infections

122
Q

Are A. fumigatus or A. flavus dimorphic?

A

NO

123
Q

How do A. fumigatus or A. flavus exist?

A

Mold

124
Q

How do you contract the infection?

A

Inhalation of condidia

125
Q

What causes the pathology in affected individuals?

A

Hyphal growth of the mold

126
Q

Would you see septations in the hyphae’s of an aspergillosis infection?

A

YES

127
Q

What is a signature clinical finding of patients with an aspergillosis infection?

A

A “fungus ball”

128
Q

What is a fungus ball?

A
  • A colonization of fungi in pre-existing lung lesions
  • Consists of a lot of hyphae and cellular debris
  • Unilaterally found
  • Asymptomatic, but you can see it on an x-ray
  • Can be memtrated by blood vessels, causing it to spread to the liver
129
Q

When does invasive or disseminated infection occur?

A
  • Patients with leukemia, neutropenia or organ transplant recipients
130
Q

When will this infection be fatal?

A

If it is ot detected

131
Q

What will an invasive infection cause?

A

Invasion of the lung parenchyma following infection will cause fever, hemoptysis, and chest pain

132
Q

Where will it spread or disseminate to?

A
  • GI
  • Brain
  • LIver
  • Kidney
133
Q

How do you diagnose aspergillosis?

A
  • Observation of hyphal elements in sputum or biopsy material
  • Culture confirmation.
134
Q

What will you see in a tissue section of aspergillosis?

A

Septate hyphae ***

They will be branching at a 45 degree angle ***
think A = 45 degree angle = Aspergillosis

135
Q

HOw do you treat an asperigillosis infection?

A
  • Azole (newer – voriconazole)
  • Echinocandin
  • Amphotericin B
  • Surgical removal of Aspergillomas

Microbiology Exam 2 (8 decks)

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