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24 Cards in this Set
- Front
- Back
What are pseudohyphae?
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Long chains of unicellular yeast cells
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Molds are aka?
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Mycelia
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What are dimorphic fungi? Examples?
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Growing as spores in the environment, often as yeast in the body. Histoplasma, blastomyces, and coccidioides
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Which fungus has a polysaccharide capsule?
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Cryptococcus neoformans
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What's the classic way of getting sporotrichosis? Manifestations?
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Gardener getting a rose thorn prick, with the gradual formation of a subQ nodule. This necroses and ulcerates, spreading along lymphatic tracts up the arm
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How is sporotrichosis treated?
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Oral potassium iodide or amphotericin B.
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What are the three fungi that cause systemic disease in humans? They are endemic to where?
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Histoplasma, blastomyces, and coccidioides. Histo and blasto are Mississippi river fungi, wheras coccidioides is found in the southwest.
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The disease mechanism of systemic fungal infections is similar to...? Describe in general...?
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Similar disease mechanism to TB.
1. Inhalation of spores 2. Local lung infection followed by bloodstream dissemination. 3. In most people, the fungi are then destroyed by cell-mediated immunity. |
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What are the clinical presentations of the systemic fungal infections?
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1. Asymptomatic
2. Pneumonia - chest Xray infiltrates, granulomas with calcifications can follow resolution of the pneumonia. 3. Disseminated disease - meningitis, bone lytic granulomas, skin granulomas/ulcers, and other organ lesions |
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What's the best way of diagnosing systemic fungal infections?
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Tissue biopsy
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Treatment for chronic or disseminated fungal disease is usually...?
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Itraconazole or amphotericin B
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What is the major manifestation of cryptococcus infection? Seen in which population?
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Meningoencephalitis (3/4 of cases occur in immunocompromised persons such as AIDS patients)
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Why is cryptococcal meningitis fatal without treatment?
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Cerebral edema progresses to eventual brainstem compression.
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What is the key to cryptococcus diagnosis?
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Lumbar puncture and analyzing the CSF. Also make sure to measure opening pressure.
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What is the usual treatment of an AIDS patient with cryptococus infection?
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Amphotericin B and flucytosine
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Describe where Candida can be seen in normal immunocompetent hosts?
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1. Oral thrush
2. Vaginitis 3. Diaper rash |
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What are the risk factors for developing vaginitis?
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Women taking antibiotics, oral contraceptives, or during menses and pregnancy
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What are the more serious manifestations of Candida in immunosuppressed patients? What should be examined in these patients?
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1. Esophagitis
2. Disseminated - Can invade virtually every organ Examine retina for cotton spots, check blood cultures. |
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What is an aspergilloma?
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An aspergillus fungal ball in the lung cavitations from TB or malignancies.
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What mycotoxin is produced by Aspergillus? What does it do?
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Aflatoxin - causes liver damage and liver cancer.
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What disease does Actinomyces cause? What is an important microscopic feature of Actinomyces?
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Eroding abscesses following trauma to the mucous membranes of the mouth or GI tract.
Sulfur granules. |
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Describe Nocardia microscopically? Frequently misdiagnosed as?
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Partially acid-fast beaded branching thin filaments. Frequently misdiagnosed as TB.
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Describe treatment for Actinomyces and Nocardia?
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Treatment is a SNAP!
Sulfa for Nocardia, Actinomyces give Penicillin. |
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Describe the adverse effects (and ways to mitigate them) of Amphotericin B?
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1. Renal toxicity (administer with normal saline)
2. Acute febrile reaction (give aspirin) 3. Anemia 4. Phlebitis of the vein at the IV site |