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19 Cards in this Set
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Systemic mycoses |
Can cause pneumonia and disseminate. All are caused by dimorphic fungi: cold (20C) = mold; Heat (37C) = yeast. The only exception is coccidioidomycosis, which is spherule (not yeast) in tissue. Treatment: fluconazole or itraconazole for local infection' amphotericin B for systemic infection. System mycoses can form granulomas (like TB) but cannot be transmitted person-to-person (unlike TB) |
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Histoplasmosis |
Systemic mycoses Endemic location and pathologic features: Mississippi and Ohio river valleys. Macrophage filled with Histoplasma (smaller than RBC) Histo Hides (within macrophages). Seen in bird (e.g. starlings) or bat droppings |
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Blastomycosis |
Systemic mycoses Endemic location and pathologic features: Eastern United states and Central America. Causes inflammatory lung disease and can disseminate to skin and bone. Forms granulomatous nodules. Broad-base budding (same size as RBC) Blasto buds broadly |
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Coccidioidomycosis |
Systemic mycoses Endemic location and pathologic features: Southwestern United States, California. Causes pneumonia and meningitis; can disseminate to skin and bone. Case rate increase after earthquakes (spores in dust thrown into air -> inhaled -> spherules in lung). Spherule (much larger than RBC) filled with endospores |
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Paracoccidioidomycosis |
Endemic location and pathologic features: Latin America. Budding yeast with "captain's wheel" formation (much larger than RBC). |
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Tinea (dermatophytes) |
Cutaneous mycoses Tinea spits, Tinea corporis, Tinea curries, Tinea pedis, Tinea unguium. Clinical name given to dermatophyte (cutaneous fungal) infections. Dermatophytes include Microsporum, Trichophyton, and Epirdermophyton. Branching septet hyphae visible on KOH preparation with blue fungal stain. |
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Tinea capitis |
Cutaneous mycoses occurs on head, scalp. Associated with lymphadenopathy, alopecia, scaling |
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Tinea corporis |
Cutaneous mycoses occurs on torso. Characterized by erythematous scaling rings ("ringworm") and central clearing. Can be acquired from contact with an infected cat or dog. |
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Tina cruris |
Cutaneous mycoses occurs in inguinal area. Often does not show the central clearing seen in tinea corporis |
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Tinea pedis |
Cutaneous mycoses Three varieties: interdigital (most common), Moccasin distribution, Vesicular type |
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Tinea unguium |
Cutaneous mycoses onychomycosis; occurs on nails |
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Tinea (pityriasis) versicolor |
Cutaneous mycoses Caused by Malassezia app (Pityrosporum spp), a yeast-like fungus (not a dermatophyte despite being called tinea). Degradation of lipids produces acids that damage melanocytes and cause hypo pigmented and/or pink patches. Can occur any time of the year, but more common in summer (hot, humid weather). "spaghetti and meatballs" appearance on microscopy. Treatment: selenium sulfide, topical and/or oral anti fungal medications |
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Opportunistic fungal infections |
Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans, Mucor and Rhizopus spp, Pneumocystis jirovecii, Sporothrix schenckii |
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Candida albicans |
Dimorphic; forms pseudohyphae and budding yeasts at 20C, germ tubes at 37C. Systemic or superficial fungal infection. Causes oral and esophageal thrush in immunocompromised (neonates, steroids, diabetes, AIDS), vulvovaginitis (diabetes, use of antibiotics), diaper rash, endocarditis (IV drug users), disseminated candidiasis (to any organ), chronic mucocutaneous candidiasis Treatment: topical azalea for vaginal; nystatin, fluconazole, or caspofungin for oral/esophageal; fluconazole, caspofungin, or amphotericin B for systemic |
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Aspergillus fumigatus |
Septet hyphae that branch at 45 degree acute angle. Produces conidia in radiating chains at end of conidiophore. Causes invasive aspergillosis, especially in immunocompromised and this with chronic granulomatous disease. Can cause aspergillomas in pre-existing lung cavities, especially after TB infection. Some species f Aspergillus produce Aflatoxins, which are associated with heptaocellular carcinoma. Allergic bronphopulmonay aspergillosis (ABPA): hypersensitivity response associated with asthma and cystic fibrosis; may cause bronchiectasis and eosinophilia |
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Cryptococcus neoformans |
5-10um with narrow budding. Heavily encapsulated yeast. Not dimorphic. Found in soil, pigeon droppings. Acquired through inhalation with hematogenous dissemination to meninges. Culture on Sabouraud agar. Highlighted with India ink (clear halo) and mucicarmine (red inner capsule). Latex agglutination test detects polysaccharide capsular antigen and is more specific. Causes cryptococcosis, cryptococcal meningitis, cryptococcal encephalitis ("soap bubble" lesions in brian), primarily in immunocompromised |
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Mucor and Rhizopus spp |
Irregular, broad, nonseptate hyphae branching at wide angles. Mucormycosis. causes disease mostly in ketoacidotic diabetic and/or neutropenic patients (e.g. leukaemia). Fungi proliferate in blood vessel walls, penetrate cribriform plate, and enter brain. Rhino cerebral, frontal lobe abscess; cavernous sinus thrombosis. Headache, facial pain, black necrotic eschar on face; may have cranial nerve involvement. Treatment: surgical debridement, amphotericin B |
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Pneumocystis jirovecii |
Causes Pneumocystis pneumonia (PCP), a diffuse interstitial pneumonia. Yeast-like fungus (originally classified as protozoan). Inhaled. Most infections are asymptomatic. Immunosuppression (e.g. AIDS) predisposes to disease. Diffuse, bilateral ground-glass opacities on CXR/CT. Diagnosed by lung biopsy or lavage. Disc-shaped yeast seen on methenamine silver stain of lung tissue. Treatment/prophylaxis: TMP-SMX, pentamidine, dapsone (prophylaxis only), atovaquone. Start prophylaxis when CD4+ count drops to <200 cells/m3 in HIV patients |
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Sporothrix schenckii |
Sporotrichosis. Dimorphic, cigar-shaped budding yeasts that grows in branching hyphae with rosettes of conidia; lives on vegetation. When spores are traumatically introduced into the skin typically by a thorn ("rose gardener's" disease), causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis). Disseminated disease possible in immunocompromised host. Treatment: itraconazole or potassium iodide. |
