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Commensal
Pathogenic
Opportunistic infection in immunocompromised individuals
superficial and deep of the skin, mucosal, lung, systemic
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Dermatophyte infections
Candida albicans
skin
candidiasis (thrush); mucosal and systemic
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Aspergillus
Zygomycoses
lung and systemic
Nasal and maxillary sinuses
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Cryptococcus
Histoplasma capsulatum
Lung and brain
lung, oral
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What are the 3 types of responses to fungal infections?
- 1. minimal - dermatophyte (skin) ringworm, tinea
- 2. acute - candidiasis
- 3. granulomatous - histoplasmosis
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What is the etiology of histoplasmosis?
- Histoplasma capsulatum
- It is a mold in soil, bat/bird guano, yeast in tissue
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What is histoplasmosis?
A disease caused by the fungi histoplasma capsulatum that is spread by inhaling spores --> it is a pulmonary disease. The organism is often found in soil.
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What are the clinical features of histoplasmosis?
- 1. mild, flu-like symtpoms
- 2. 2-3 weeks after infection, T-cell mediated granulomatous inflammation, antibody is produced several weeks later
- 3. acute lungs 1%, 2 week duration, calcification of hilar nodes
- 4. chronic lungs immunosuppressed in elderly
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What are oral manifestions of histoplasmosis?
- - disseminated (diffused) to extrapulmonary sites.
- - It is rare and found in 2-10% of HIV pts.
- Oral:
- - usually associated with disseminated disease
- - tongue, palate, buccal mucosa, gingiva, floor of the mouth
- - mimics malignancy clincially
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What is a differential diagnosis of histoplasmosis?
It looks like oral cnacer and can be evaluated as non-cancerous because often the patient will also have pulmonary disease.
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what are the histologica signs of Histomplasmosis?
- granulomatous inflammation
- pseudoepitheliomatous hyperplasia (PEH)
- Periodotc acid Schiff reagent, methenamine silver
- yeasts 1-2u in diameter (this is what mimics cancer)
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How do you diagnose histoplasmosis?
- tissue sections
- serological testing for antibodies
- detection of H.capsulatum antigen
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What is the treatment for histoplasmosis?
- actue is usually self limiting
- chronic: amphotericin B, ketoconazole, itraconazole
- Disseminated has the same treatment as chronic
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What is the prognosis for histoplasmosis?
- chronic w/out treatment may be progressive and death in 20%
- disseminated disease mortality 20% w/ treatment
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Balstomyces dermatitidis
A mold in moist soil that causes blastomycosis
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What are some other facts about Blastomycosis?
- It is more common in males
- It is rare in immunocompromised individuals
- infections are acquired by inhaling spores (often after rain)
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What are the clinical features of blastomycosis?
- acute pneumonia: fever, cough, night sweats, chest pain,
- chronic is more common and mimics TB: low grade fever, night sweats, productive cough, infiltrate on chest radiograph (no calcification like histoplasmosis
- Disseminated pulmonary - skin oral (oral lesions mimic malignancy)
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What are some differential diagnosis for blastomycosis?
- TB - chest radiographs show clear diffuse infiltrate or nodes
- Malignancy - oral lesions look cancrous
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What are histological classifications of blastomycosis?
- acute and granulomatous inflammation
- pseudoepitheliomatous hyperplasia (PEH)
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what are some characteristics of the etiological agent of blastomycosis?
What stain is used to detect it?
Blastomyces dermatitidis is 8-20u in diameter with a doubly refractile cell wall w/ broad attachment btw budding cells
PAS and methenamine (Grocott-Gomori) silver special stains
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How do you diagnose blastomycosis?
- examine tissue section
- KOH (potassium hydroxide prep) digest cellular matter and leaves KOH crust.
- culture from sputum or non-fixedbiopsy specimen
- DNA probe on mycelia phase 5-7 da culture
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What is the treatment for Blastomycosis?
- usually no treatment is required
- if seriously ill (more than 2 weeks): itraconazole, ketoconazole, amphotericin B
For the serious illness, there was a 80-90% mortality prior to amphotericin B.
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Coccidioides immitis?
A dimorphic fungus found in soil that causes coccidioidomycosis
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How is coccidioidomycosis transmitted?
- It is acquired via inhalation
- It has a 1-4 week incubation period
- It is more common in blacks and fillipinos
- It causes a disseminated disease (body wide spread) disease in immunocompromised patients
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What is the histological presentation of coccidioidomycosis?
- You find C. immitis with acute and granulomatous inflammation
- Special stains of PAS and methenamine silver are used to ID it
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What is the diagnosis of coccidioidomycosis?
- Tissue specimen
- Cytology
- Culture
- Serological testing and skin testing
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What is the treatment of coccicioidycosis?
In immunosuppresed/life treatening condition of disease: ketoconazole or flucanzole with amphotericin B
The prognosis is pretty good but HIV patiens will need life-long daily antifungal medications.
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Cryptococcus neoformans
A fungi who's inhaled spores cause cryptococcosis
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What are the manifestations of cryptococcosis?
It is caused by cryptococcus neoformans and usually manifests as flu-like symptoms.
In immunosuppresed patients it can can become disseminated and spread to the skin, menininges, bones, and prostate.
Oral lesions are rare
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What is the treatment of cryptococcosis?
200mg fluconazole 2x daily for 8 weeks; then 200mg maintenance for life
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What is the histology of cryptococcosis?
- granulomatous inflammation
- 4-6y round to oval mo w/ clear capsule
- It is usually detected with PAS methanmine silver or mucicamine
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How do you diagnose cryptococcosis?
- biopsy
- culture
- detection of crytococcal antigen in CSF - the meninges are often invovled so some CSF can also be used to find the histological features of the MO
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What is the treatment for cryptococcosis?
- amphotericin B and flucytosine
- fluconazole and itraconazole
prognosis depends on control of underlying condition and response to antifungal meds
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Zygomycosis?
An oppertunistic infection usually caused by saprophytic (an organism that lives on dead material) mo such as Absidia, Mucor, and Rhizopus.
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How is Zygomycosis spread?
Spores are usually inhalled in a rhinocerebral form. It is poorly controlled in diabetes, leukema, and other systemic disorders.
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What are the clinical features of Zygomycosis?
- Nasal obstruction
- discharge
- facial pain
- headache
- visual distrubance
- facial swelling
- intraolra swelling/ulceration
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What are the radiographic features of Zygomycosis?
- Opacification of sinus due to destruction of bone
- It mimics malignancy
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What is another agent of Zygomycosis?
Mucromycosis, phycomycosis
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What is the histology of Zygomycosis?
- Large right angle branching nonseptate hyphae
- invovles small BV walls and occlude (fungal angilitis)
- Tissue invasion
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What is the treatment of Zygomycosis?
- Surgical debridement
- Antifungal medication-amphotericin B
- Contorl underlying disease
It has a poor prognosis
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Why does Zygomycosis have a poor prognosis?
The antifungal medication - amphotericin B can cause renal failure.
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Aspergillosis?
- An allergic reaction in normal host or invasive in immunocompromised
- It is caused by Aspergillus Saprophytic mo in soil or water (A. Falvus and A. Fumigatus are the most common)
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How is Aspergillosis spread?
Infection results from inhalation of spores (possible to be spread through hospital ventilation systems)
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What are the clinical features of Aspergillosis?
- allergic symtpoms such as allergic fungal sinusitisLow grade infection of sinus such as a fungus ball (aspergilloma)
- Localized pain, swelling, yellow or black ulcer
- Disseminated lung --> CNS, eye, skin, bone, GI (leukemia, corticosteroids)
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