31 - Fungal Infections of the Respiratory Tract Flashcards
1
Q
Review: Fungi which can grow as both yeast and mold are know as?
A
Dimorphic
2
Q
Review: An India ink test is used to aid in the identification of?
A
Cryptococcus neoformans
3
Q
Review: - What looks like long strings of fungi with septations in the string?
A
Septate hyphae
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
5
Q
Where do we find zygomycetes in the enviroment?
A
Soil, vegetation and food (fruits and bread)
6
Q
What are predisposing factors to contracting a zygomycoses (or mucormycosis) infection?
A
- Immunosuppression***
- Diabetes
- Burn patients (no protective skin/innate immunity
7
Q
How common are (or mucormycosis) infections in healthy individuals?
A
RARE
8
Q
What are three types of zygomycetes?
A
Rhizopus
Absidia
Mucor
9
Q
What is the common appearance of these zygomycetes?
A
Non-septate hyphae
10
Q
What is the most common form of zygomycosis?
A
Rhinocerebral zygomycosis
Over 50% of cases
11
Q
Which population is most likely to contract Rhinocerebral zygomycosis?
A
Diabetics *** :(
12
Q
Where does the infection typically originate?
A
Sinuses - by inhalation of spores
Watch for Shannon getting a sinus infection
13
Q
Where can this sinus infection spread to?
A
Extends to neighboring tissues (nose, adjacent sinuses, the hard palate, eye, and brain)
14
Q
What does progression to the brain cause?
A
Progression to the brain results in altered mental status, coma and death
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)
16
Q
How do you diagnose zygomycoses?
A
- Microscopic observation of hyphal elements in clinical material (sputum, etc)
- Culture confirmation
17
Q
What would you see in a microscopic observation of zygomycoses?
A
- No septations
- Very wide, broad hyphae
- Branching at 90 degrees
18
Q
How do you treat zygomycoses?
A
Amphotericin B
19
Q
What is Candidiasis?
A
A yeast infection that is caused by a yeast in the genus family Candida, MOST COMMONLY candida albicans***
20
Q
Is candida albicans considered normal flora?
A
Yes, on the skin, mucus membranes and GI tract it is
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***
22
Q
What do we call oral candidiasis?
A
THrush
23
Q
Who is at risk for developing thrush?
A
- Infants
- Adults on steroids, antibiotics, etc.
- AIDS patients
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
25
How do you diagnose thrush?
- Clinical observation
| - Culture is not necessarily needed
26
How do you treat thrush?
Oral formulations (mouth washes or lozenges) of nystatin and azole compounds
27
What are systemic mycoses?
Fungal infections that begin with a pulmonary infection by inhaling fungal elemetns, but can cause systemic infections
28
What are the five systemic mycoses?
```
1 - Histoplasma capsulatum
2 - Blastomyces dermatitidis
3 - Paracoccidioides brasiliensis
4 - Coccidioides immitis
5 - Cryptococcus neoformans
```
29
What is important about coccidioides imitis?
Dimorphic fungi
- Mold in environment
- Yeast in the body
30
Would you expect to see hyphe in the body of someone infected with coccidiodes imitis?
NO ***
| - It is not a mold in the body, so no hyphe
31
What is important abotu cryptococcus neoformans?
- Encapsulated yeast in the environment and body
| - Found worldwide
32
What is histoplasmosis?
A fungal infection found in distinct parts of North and Central America
AKA cave dwellers, Darling's ***
33
Where have we seen endemics in the US of histoplasmosis?
Mississippi river and ohio river valleys
50-80% of the population of this area are skin test positive
34
What is histoplasmosis cased by?
Histoplasma capsulatum
35
Where do we find Histoplasma capsulatum?
- Soil in humid climates
- Bird/bat dropings
- Chicken coups
36
How do you aquire histoplasmosis?
Inhalation of microcondria from environment
37
What do these fungi look like under a microscope?
Macroconidia of H. capsulatum have a characteristic tuberculate (round bump) appearance
38
What are the symptoms of histoplasmosis?
95% of exposed/infected individuals appear to be asymptomatic.
39
What is the disease mechanism of histoplasmosis?
Inhaled fungal spores are phagocytosed by pulmonary macrophages and convert to their yeast form.
40
What happens once the yeast form is in the body?
The organism can replicate within macrophages and spread through the lymphatic and reticuloendothelial system
41
What is pulmonary histoplasmosis?
- A mild flu-like illness with a dry cough, fever, and fatigue
- Develops several weeks after exposure and improves within 2 to 3 weeks
42
Do most cases need an antifungal?
No - resolve on their own from CMI
43
What clincial sign is common?
Calcification of pulmonary lesions is common
44
What can occur in severe infections?
Pulmonary infiltrate and chest pain are more common in severe infections.
45
What happens when the acute infection becomes a disseminated disease?
Two things could happen:
- Could be a severe accute illness
- Could be a chronic and slowly debilatating illness
46
What are symptoms of disseminated histoplasmosis?
Individuals experience fever, night sweats, anorexia, weight loss, and fatigue in addition to respiratory symptoms
47
Where can the infection spread to?
Liver, spleen, lymph nodes
48
How do you diagnose histoplasmosis?
Direct observation of organisms (yeast form) in tissues or clinical samples (sputum)
49
Why is this hard to detect?
Detection of yeast forms in tissue or sputum samples is difficult due to their small size and lack of distinctive morphology.
50
How do you treat histoplasmosis
Amphotericin B
51
What do you do if your pateint has AIDS and this infection?
Often require lifelong suppressive therapy to prevent relapse frequently with azoles (less toxic)
52
What is Blastomycosis?
An endemic in the Ohio and Mississippi river valley and to a lesser extent the Missouri and Arkansas river basins
53
What fungi causes blastomycosis?
Blastomyces dermatitidis
54
What type of fungus is Blastomyces dermatitidis?
A dimorphic fungi
```
Environment = mold
Body = yeast
```
55
What does the yeast from a body sample look like?
***
Larger size and very thick cell walls
***
56
What is the primary disease with blastomycosis?
Primarily a pulmonary disease, with the potential to disseminate causing ulcerative lesions of the skin, bone, and urogenital tract.
57
How do you contract blastomycosis?
Acquired through inhalation of spores from the environment
58
Are most cases symptomatic?
No, most are asymptomatic
59
There are three types of clinical cases of blastomycosis. WHat are they?
- Acute
- Chronic
- Dissemminated
60
What is acute blastomycosis?
Acute: cough, fever, chills, arthralgia, myalgia, sputum production*
61
What might acute present like?
Bacterial pneumonia (chest pain, sputum production)
62
What is chronic pulmonary blastomycosis?
cough, fever, night sweats, weight loss, sputum production (mimics TB)
Typically resolves without intervention
63
What is seen in the disseminated disease of blastomycosis?
Disseminated disease
- Skin lesion - ulcerative and disfiguring (painless)
- Bone infection - necrosis and granuloma formation
- Prostate appears to be especially prone to infection.
64
How do you diagnose blastomycosis?
- Observation of distinct yeast forms in sputum or biopsy material
- Cultivation may take 2-3 weeks
65
What do you treat blastomycosis with?
If you treat at all...
- Amphotericin B
- Azole
66
What is paracoccidiomycosis?
A disease limited to the tropical regions of S and central America and mostly MEN
67
What causes paracoccidiomycosis?
Paracoccidioides brasiliensis (brazil = south and central america = easy to remember)
68
What type of fungi is Paracoccidioides brasiliensi?
DImorphic
69
Why is it more common in men?
Inhibited by estrogen
70
How will Paracoccidioidomycosis present?
- Most infections are asymptomatic.
- Pulmonary infection is similar to histoplasmosis and blastomycosis.
- Disseminated disease presents as chronic cutaneous and mucocutaneous ulcers
71
How do you diagnose?
Direct observation, cultivation, and serology
72
What will you see in teh microscope of a patient with paracoccidiodomycosis?
Distinctive forms observed under microscope:
- Mickey mouse ears
- Ships wheel
73
What is coccidioidomycosis?
A common fungi infection seen in the US, mostly in California and Arizona due to the drought-rain-drought pattern
74
What does the drought-rain-drought pattern contribute?
Spores in dry, germinate in rain, drought makes more spores form
75
How do they spread?
large numbers of fungal elements present in blowing dust
76
What type of fungi is coccidioidomycosis?
Dimorphic
77
Following inhalation the fungus converts into a ________
spherule ***
78
What is a spherule?
- A multinucleated structure
| - Produces hundreds of single nucleated spores
79
What form do spores convert to in the enviroment?
Mold
80
What form do spores convert to in the body
New spherules
81
What percent of coccidioidomycosis patients are asymptomatic?
60%
82
What is the clinical presentation of coccidioidomycosis if the patient develops symptoms?
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
Does this spontaneously resolve?
Yes - Most individuals spontaneously resolve the infection in 2 to 3 weeks
84
What happens if it becomes a progressive chronic pulmonary disease?
Progressive chronic pulmonary disease which may result in cavity formation and take years to resolve
85
How commo is a dissemiated disease from coccidiodomycosis?
RARE
86
When does it typically develop if it does?
Within one year of infection
87
What will the disseminated disease infect?
Bones, joins, CNS
88
What can this lead to in the CNS?
Coccidial meningitis
89
What do you see in coccidial meningitis?
develops slowly with increasing headache, fever, stiff neck, and other neurological signs. If untreated, the disease is frequently fatal
90
How do you diagnose coccidiodomycosis?
Direct observation
- distinct spherule forms in sputum or biopsy****
Cultivation
Serology
91
How do you treatcoccidiodomycosis?
- Azole
| - Amphotericin B (meningitis and disseminated disease)
92
What is cryptococcosis?
A fungal infection from Cryptococcus neoformans ***
93
What is the leading form of fungal meningitis?
***********
Cryptococcal meningitis is the leading form of fungal meningitis. ****
94
Is Cryptococcus neoformans a dimorphic fungi?
NOOOOOO***
95
What is Cryptococcus neoformans in terms of fungal form?
An encapsulated yeast
96
Where can you find Cryptococcus neoformans
| in the environemtn?
Bird droppings, contaminated soil ***
97
What is the primary disease we see with Cryptococcus neoformans?
Pulmonary disease
98
How does a patient with a Cryptococcus neoformans pulmonary disease present?
- asymptomatic or a mild, spontaneously resolving, influenza like illness
- little sputum production
- little damage to the lung (granuloma or cavitation
99
What is the disseminated disease of crytococcosis?
Sink and bone lesions
100
How does cryptococcosis meningitis present?
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
What group is at increased risk?
AIDS/immunosuppressed
102
How do you diagnose crytococcosis?
*******
India ink stain
*********
103
How do you treat cryptococcosis meningitis?
- 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
Review: how will blastomycosis appear?
***
Broad-based budding yeast
105
Review: how will coccidiodomycosis appear?
***
Spherules containing endospores
106
Review: how will histoplasmosis appear?
***
Intracellular budding yeast
107
Review: how will paracoccidiodomycoses appear?
***
Large multiply budding yeast
108
What is Pneumocystis jiroveci (carinii)?
A fungi that leads to a highly lethal form of pneumonia
PCP: Pneumocystis carinii pneumonia
109
When populations do we see this in?
AIDS/immunocompromised
110
What percentage of AIDS patients will suffer from this
80%
111
What percent die from it?
30-50%
112
What type of organism is Pneumocystis jiroveci?
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
How are individuals infected with PCP?
Inhalation of cysts
114
Will PCP ever be asymptomatic?
Yes, in healthy individuals
115
If PCP is symptomatic, how will it present?
Dyspnea, nonproductive cough, and fever
116
If the patient progresses, what will we see?
- Patient develops interstitial pneumonitis with cellular infiltrate
- Weakness, tachypnea (labored breathing), and cyanosis
- Death results from asphyxiation
117
How do you diagnose PCP?
Not easy... You will need to know what you are looking for and use a special staining technique
118
How do you treat PCP?
Trimethoprim-sulfamethoxazole
(to interfere with the folate synthesis pathway of the organism)
In AIDS...
- Prophylaxis and suppressive therapy
119
What is aspergillosis?
A fungal infection caused by A. fumigatus or A. flavus
120
How pathogenic is aspergillosis?
Aspergillus is rarely pathogenic in individual with normal immune status
121
What types of clinical diseases to we see?
- Primarily a pulmonary infection
| - Can disseminate to a wide range of infections
122
Are A. fumigatus or A. flavus dimorphic?
NO
123
How do A. fumigatus or A. flavus exist?
Mold
124
How do you contract the infection?
Inhalation of condidia
125
What causes the pathology in affected individuals?
Hyphal growth of the mold
126
Would you see septations in the hyphae's of an aspergillosis infection?
YES
******
127
What is a signature clinical finding of patients with an aspergillosis infection?
A "fungus ball"
***
128
What is a fungus ball?
- 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
When does invasive or disseminated infection occur?
- Patients with leukemia, neutropenia or organ transplant recipients
130
When will this infection be fatal?
If it is ot detected
131
What will an invasive infection cause?
Invasion of the lung parenchyma following infection will cause fever, hemoptysis, and chest pain
132
Where will it spread or disseminate to?
- GI
- Brain
- LIver
- Kidney
133
How do you diagnose aspergillosis?
- Observation of hyphal elements in sputum or biopsy material
- Culture confirmation.
134
What will you see in a tissue section of aspergillosis?
Septate hyphae ***
| They will be branching at a 45 degree angle ***
think A = 45 degree angle = Aspergillosis
135
HOw do you treat an asperigillosis infection?
- Azole (newer – voriconazole)
- Echinocandin
- Amphotericin B
- Surgical removal of Aspergillomas
