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23 Cards in this Set
- Front
- Back
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Fungal Infections
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increasingly common, not virulent but opportunistic especially in the immunocompromised, produce toxins not relevant to humans but disease from bulk and host response
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Fungal Biology
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eukaryotic, non-motile, saprophytic or parasitic, Cell wall with glucan and chitin, cell membrane with ergosterol, hyphae or spores
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Fungal Cell Structure
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Yeasts: unicellular, budding
Molds: hyphae, mycelia, spores Dimoprhs: both |
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What are the three different types of fungal infections?
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Superficial/Cutaneous
Subcutaneous Systemic: dimorphs and opportunistic yeasts and molds |
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Superficial Fungal Infections
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Dermatophytes producing keratinase
Grow as saprophytes Clinical: tinea: corporis, cruris, unguum, capitis, pedis, ringworm |
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How to diagnose dermatophyte infections?
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morphology: active border (psoriasis) no mucosal involvement (candidiasis)
KOH prep UV Fluorescence Rare Biopsy |
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Malassezia Furfur and Tinea Versicolor
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MF: lipophilic yeast that feeds on skin lipids cause pigment change and itch
TV: adolescence, fungemia with lipid infusion |
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Subcutaneous Fungal Infections
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Introduced through skin by foreign body, grow in underlying tissues and spread to lymphatics, usually local disease but may disseminate to bones, common in poor countries: mycetoma of feet
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Sporotrichosis
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Sporothrix
Dimorphic soil fungus (mold in soil, yeast in body) Ulcerating nodules along hard cord Travel along lymphatics elicit pyogenic granulomatous |
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Systemic Fungal Infections Specific Dimporhs
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Histoplasmosis, Coccidioidomycosis, blastomycosis
dimorphic Respiratory Acquisition Geographic Similar to TB Infects Normal Hosts |
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Histoplastamosis
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Soil dimorph (mold in soil, yeast in body)
Soil with high Nitrogen, OHIO valley, South America Chicken coops and bat caves Hematogenous Dissemination Skin Test Reactivity Walled off Granulomaa May cause cavitary lungs, may reactive years later |
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Coccidioidomycosis
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mold in soil, spherules/endospores in host
Arid areas, Southwest US, Mexico and below Hematogenous Dissemination Walled of Granulomas Valley Fever, Flu Like Skin, Bone, CNS Dissemination |
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Coccidioidomycosis Life Cycle
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Saprophytic spores released, form tubular structure, forms anthroconidium, inhaled and becomes parasitic, forms a sphenule with many more spores released
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Blastomycosis
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Humid woodlands, dams and peanut farms, organic debris
No antigen test Lung Diseases Disseminated Disease: skin, bone, UTI |
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Systemic Fungal Infections Opportunists
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omnipresent
yeast or molds many ways to infect host response varies syndromes vary no lasting immunity |
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Cryptococcosis
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Yeast with polysaccharide capsule
bioterrorism, inhalation Transient or lung disease CNS invasion Communicating hydrocephalus, meningoencephalitis, fever, headache stiff neck, delirium (India ink, antigen assay) |
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Candidiasis
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yeasts with hyphal forms
normal flora change in environment leads to overgrowth: wet skin, hormones, foreign bodies change in immunity leads to invasion: immaturity, dysfunction Overide normal host immunity |
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Invasive Candidasis
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eliminate normal flora
breach normally by biofilm or catheter defective leukocytes critically ill with multiple risks: hospital, antibiotics, catheters fever, leukocytosis, organ fails, abscesses in organs, endocarditis with large vegetation and emboli |
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Are Candida Virulent
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environmentally tolerant
hydrolases, beta proteases and phospholipases adheres to plastic invade GI and renal epithelium hypahe prevent phagocytosis infection vs invasion difficult (treat by restoring missing defense) |
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Aspergillosis
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mold
inhalation ellicit allergy, grow in cavity, invade blood and spread allergic bronchopulmonary aspergillosis pneumonia |
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Mucormycosis
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molds
inhalation relentless growth acidosis, diabetes, neutrophil fails, iron overload fulminant pneumonia to infarcton, sinusitis brain abscess |
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Multistate Fungal Outbreak
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Black Mold
FLuke 496 cases, 19 states, 36 deaths, |
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Antifungal Defenses
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Intact Skin (D, C)
Lymphocyte Function (Di, Cr, C) neutrophils (C, A, M) body millieu (C, M) |
