Test 4/final Flashcards
Sporotrichosis
Sporothrix schenckii (subcutaneous)
Rose gardener’s disease
Cigar shaped yeast form
Lymphatic involvement
Chromoblastomycosis
Fonsecaea, Phialophora, Cladophialophora (subcutaneous)
Tissue morphology: Sclerotic/medlar bodies (yeast)
Verrucous califlower-like lesions on lower extremities (bare feet)
Phaeohypomycosis
Cladophialophora bantiana (brain lesions) = fatal (subcutaneous)
Usually forms a cyst on the hands
Tissue morphology: pigmented septate hyphal fragments
Eumycetoma
Draining sinuses containing granules
(subcutaneous)
Madura foot (bare feet)
*can also be caused by actinomycetes (bacteria)
Dermatophytes
Cutaneous
Digest keratin (nutrient source)
Tinea barbae, corporis, capitis, cruris (groin), pedis, manuum, unguinum (onchomycosis)
*favus variant tinea capitis = scutula that covers scalp (gross)
Pityriasis (tinea versicolor)
Superficial
Malasserzia furfur
Hyper/hypopigmented maculae usually on trunk/proximal limbs
Tinea nigra
superficial
Hortae Werneckii
Brownish maculae on palms and soles (looks like melanoma)
Black Piedra
Piedraia hortae (superficial)
Microscopic = discrete, hard, dark brown nodules on hair
White piedra
Trichosporan spp (superficial)
Microscopic = soft,white to yellowish nodules loosely attached to hair
Endemic, Dimorphic fungi
coccidioidomycosis histoplasmosis blastomycosis paracoccidioidomycosis penicilliosis marneffi
Coccidioidomycosis
Mnemonic: Coccidio Crowds san joaquin valley, “valley fever”
Coccidioides immitis (califiornia) Coccidioides posadasii (arizona)
Self-limited pulmonary febrile illness, lung lesions, valley fever (30%), highest incidence >65
*Microscopic = Spherule filled with endospores
Histoplasmosis
Mnemonic: Histo Hides within macrophages, bird and bat droppings
Histoplasma capsulatum
Found in soil, bat, and bird droppings
Asymptomatic (95%), pneumonia, chronic cavitary fibrosing mediastinitis, disseminate via RES, sepsis
- Microscopic = macrophage filled histoplasma
- Urine histoplasma antigen testing
African Histoplasmosis
larger, thick-walled yeast cells
pronounced giant cell formation in infected tissue
diminished pulmonary involvement
greater frequency of skin and bone lesions
Blastomycosis
Mnemonic: Blasto buds broadly
Blastomyces dermatitidis
Epidemiology: soil, near inland waterways
Asymptomatic (50%, more virulent), pulmonary infection, subcutaneous nodule, disseminate to bone or skin (immunocompromised)
*Microscopic = bud attached to parent by broad base
Paracoccidioidomycosis
Mnemonic: Paracoccidio Parasails with the captain’s wheel all the way to latin america
Paracoccideioides brasiliensis
Epidemiology: central-south america
Asymptomatic, nodular lesions in lungs, mucocutaneous orolabial and nasal lesions
*Microscopic = multiple budding yeasts the buds are attached to the parent cell by a narrow base “pilot’s wheel”
Penicillium Marneffei
Important cause of fungal infection in HIV people in southeast asia
with AIDS = dissemination to other organs, with hallmark skin lesions on face/trunk
*Microscopic = yeast form in ellipitcal with fission septae
Cryptococosis
Opportunistic yeast (heavily encapsulated) Found in soil and pigeon droppings Cryptococcus neoformans var grubii (N. american) C. gattii = pulmonary disease in immunocompetent
pulmonary can be asymptomatic or fulminant
CNS meningitis and cyptococcoma (leading cause of fungal meningitis)
- Microscopic = wide variation in size, india ink stain capsules appears as a “halo”
- capsular polysaccharide antigen detection in serum/CSF (very sensitive)
Candidiasis
Leading cause of opportunistic fungal infection
Candida albicans is the most common species
Diagnosis via microscope = budding yeast with pseudohyphae
Germ tube test
i. Localized disease of skin and nails (e.g. diaper rash)
ii. Mucosal infections (vaginitis, oral thrush, esophagitis)
iii. Invasive disease involving bloodstream, sterile sties, and/or multiple organ systems
USUALLY CATHETER RELATED, with risk of dissemination (must pull catheter)
2. 3rd most common cause of central line associated blood stream infection (CLABSI), 40% mortality rate
3. Also infect bone, joint, peritoneum, other deep organ system involvement
Hepatosplenic candidiasis
unique to cancer patients with prolong neutropenia, microabscesses in liver and spleen, blood culture usually negative
Diagnosis of Candida problems
Early diagnosis is difficult
i. Lack of inflammatory response in host
ii. Invasive diagnostic procedures risky (organisms do not hang out in blood, have to biopsy more invasive areas)
iii. Lack of sensitive, minimally invasive assays
Risk factors for invasive candidiasis
i. Antibiotic use (increase with each additional drug)
ii. Colonization with Candida
iii. Presence of central venous catheter
iv. Neutropenia (for hepatosplenic disease)
v. Staying in the hospital too long
Aspergillosis
Mnemonic: Acute Angles in Aspergillus
Most common cause of invasive mould infection
c. Aspergillus fumigatus = most common species
Unlike candida, aspergillus do not routinely colonize healthy persons
*Diagnosis via microscope = septate hyphae that branch at acute angles (<45 degrees), conidiophore with rare fruiting bodies
Aspergillosis Clinical syndromes
Clinical syndromes
Allergic bronchopulmonary aspergillosis
Aspergilloma in pre-existing cavity = secondary colonization of a lung cavity (fungus ball, hemoptysis, occasional local invasion)
Semi-invasive aspergillosis = chronic cavitary, chronic fibrosing, chronic invasive
Invasive aspergillosis
- Extremely serious, life threatening (60-95% mortality)
- Angioinvasive with tissue infarction, rapid spread, dissemination
- Risk factors = neutropenia, corticosteroids, transplant graft vs host disease
Galactomannan test
Test for aspergillosis
polysaccharide cell wall component, test approved for serial monitoring of hematologic malignancy patients
- Not useful if patient is on antifungal therapy
- Certain antibiotics have galactomannan (false positive) = Piperacillin-tazobactam
