Fungal Infections Flashcards by Nicholas de Guzman

Fungal overgrowth in the stratum corneum epidermis disrupting melanin synthesis on trunk of body. Little response

Epidemiology caused by overgrowth of a lipophilic fungus in our normal flora. This causes fungemia in premature infants on intravenous lipid supplements

Diagnosis by KOH as spaghetti and meatball appearance

Pityriasis (tinea) versicolor, Malassezia furfur

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Superficial infection of the stratum corneum epidermis on the palmar plantar surfaces as benign, flat, dark, melononma like lesions

caused by a fungus that produces melanin, which colors the skin

Tinea nigra, dematicaeous fungi

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Prepubescent children, epidemic and spread by head gear

Non inflammatory and produces gray patches of hair

Anthropophilic tinea capitis (gray patch)

Microsporum audouinii

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Transmitted by pets or farm animals

Inflammation with tender areas called kerion, Temporary alopecia, kerion, keloid, and inflammation may result

Zoophilic tinea capitis (nonepidemic)

Microsporum canis or by Trichophyton mentagrophytes

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Chronic infection characterized by hair breakage, followed by filling of follicles with dark conidia

Black dot tinea capitis

Trichophyton tonsurans

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Acute or chronic folliculitis of the beard

pustular or dry scaly lesions

Tinea barbae

Trichophyton verruscosum

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Dermatophytic infection affects glabrous skin

Characterized by annular lesions with active border that can be pustular or vesicular

Tinea corporis

T. rubrum, T. mentagrophytes, or M. canis

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Acute or chronic fungal infection of the groin called jock itch, accompanied by athlete’s foot or nail infections

Tinea cruris

E. floccosum, T. rubrum, T. mentagrophytes, or yeasts like Candida

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Acute to chronic fungal infection of the feet called athletes foot

Common presentations: chronic intertiginous tinea pedis(white macerated tissue between the toes), chronic dry, scaly tinea pedis(hyperkeratotic scales on the heels, soles, sides of the feet), vesicular tinea pedis(vesicles and vesiculopustules)

Tinea pedis

T. rubrum, T, mentagrophytes, E. floccosum

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Highly contagious and severe form of tinea capitis with scutula (crust) formation and permanent hair loss caused by scarring
Prophylaxis of close contacts is needed

Favus In both children and adults

Favus (tinea favosa)

Trichophyton schoenleinii (permanent hair loss)

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infection of the oral cavity and manifests as white curd like patches

1) occurs in premature infants, babies on antibiotics, asthmatics not using spacers, immunocompromised patients, AIDS patients
2) can extend through GI tract causing painful gastritis

oral thrush

Mucocutaneous candidiasis

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1) yeast infection of the vagina that tends to recur
2) discharge, burning, curd like patches, inflammation
3) predisposed by diabetes, antibiotic therapy, oral contraceptive use and pregnancy
4) diagnosis via KOH mount of curd

Vulvovaginitis or vaginal thrush

Candida spp.

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1)involves the nails, moreso with them being false, skin folds of babies, obese individuals, groin and penis, lesions can be eczemoid or vesicular and pustular, predisposed by moist conditions

Cutaneous candidiasis

Candida spp.

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Cigar-shaped to oval, budding yeasts

Sporulating hyphae

Found in or on plant materials like roses, plum trees, sphagnum moss and introduced by florist’s wires, splinters, rose/plum tree thorns into subcutaneous tissues

Subcutaneous, nodular, fungal disease is not painful, can spread into the lymphatics (lymphocutaneous sporotrichosis) producing chain of lesions on the extremities

Diagnosis: clinical diagnosis confirmed and generally negative

Treatment: treated with itraconazole

Sporotrichosis, Rose Gardener’s Disease

Sporothrix schenckii

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Subcutaneous fungal disease characterized by swelling, sinus tracts erupting through skin, presence of sulfur granules

Third world countries

in soil and vegetation

Eumycotic mycetoma

Pseudoallescheria boydii and Madurella sp

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subcutaneous fungi seen in tissues as pigmented, yeast like bodies
Colored lesions that start scaly and become cauliflower like lesions, similar to Blastomycoses

Chromoblastomycosis

dematiaceous (dark) fungi

Thermally, dimorphic, facultative intracellular, fungal pathogen no capsule

Endemic in the great river plains of the Ohio, Missouri, and Mississippi Rivers, and St. Lawrence Seaway plus Latin America

Found in soil enriched with bat or bird guano as hyphae with tuberculate macroconidia and non descript microconidia. The microconidia enter the alveoli for infection. Bat caves, old chicken coups, starling roosts, high level of spores

Inhaled conidia convert to small yeast cells, phagocytosed and survive, replicate in these cells, including monocytes
Yeast form modulate the pH of the phagolysosome and trap calcium and interfere with phagocytic killing

Glucan in the cell wall play a role in fungus killing phagocytic cells
Histoplasma capsulatum has no capsule and is misnamed, stain smears, cytoplasm shrinks away from the cell wall

Acute histoplasmosis ranges from subclinical to severe pneumonia and resolves with bed rest and nutrition
Thick blood smears and blood cultures used for diagnosis because the conidia is phagocytosed alveolar mac and PMNs
Hilar lymphadenopathy and spinomegaly are prominent, Th1 response and granuloma formation used in resolution but some remain in granulomas

Histoplasmosis/Histoplasma capsulatum

Thermally dimorphic fungus found as a filamentous fungus with small conidia in rotting organic material like wood
found in Histoplasma endemic areas plus southeastern US seacoast and north through Minnesota into Canada

Conidia inhaled into the alveoli and into big, budding yeasts

found in tissue as large yeast
Cell wall of glycoprotein WI-1
Strains replicate, triggering Th2 response

acute pulmonary blastomycosis, chronic pulmonary blastomycosis, disseminated blastomycosis

Blastomycosis/Blastomyces dermatitidis in N. America

Almost always associated with the San Joaquin Valley and the Lower Sonoran Desert and those who are associated with agriculture in that region.

thermally dimorphic
Aids, pregnant women, Filipinos, African/Native Americans have increased risk of dissemination
Chronic coccidioidomycosis does not resolve

Coccidioidomycosis: Coccidiodes immitis

the most common opportunists

Very old and young, wasting or nutritional disease, pregnant, immunosuppressed, diabetes, long term antibiotic use, catheters, AIDs

Skin folds are also susceptible

Treated with fluconazole or capsofungin drugs

Signs and symptoms include alimentary, Candidemias or blood borne infections, bronchopulmonary infections

Candidiases

C. albicans

happens in neonates on intravenous lipid emulsions, resolves when lipid supplements stop

Malassezia septicemia

Associated with pigeon dropping, CNS growth, AIDS, Leukemia, once systemic it can get into the brain being hard to treat
C. neoformans possess an antigenic polysaccharide capsule

Initial symptoms include headache, followed by signs of meningitis and personality changes
Diagnosis: CSF latex particle agglutination test for Cryptococcus, india ink wet mount, culture following lysis of WBC in CSF

Treatment: with amphotericin B plus 5-fluorocytosine or fluconazole

Cryptococcal meningitis or meningoencephalitis

have septate hyphae branching dichotomously at acute angles (monomorphic)

Aspergilli

allergic bronchopulmonary asperigillosis, mucous plugs formed in lungs, does not invade lung tissues, lots of eosinophils, IgE, radiograph with presence of fungi

Aperigilloses

(fungus ball) display of recurrent hemoptysis, “air sign” Invasive aspergillosis in patients with severe neutropenia in lungs then spreading from sinus colonization. Requires aggressive treatment with voriconazole and amphotericin B

Aspergilloma

Patients with acidotic diabetes or leukemia Very invasive Preference for invading blood vessels of the brain and causing rapid decline to death Facial swelling and blood tinged exudate in the turbinates and eyes, mental lethargy, blindness and fixated pupils Diagnosis: must be diagnosed rapidly, usually by KOH mount of necrotic tissue or exudates from the eye, ear, nose Treatment is rapid, management of control of diabetes, surgical debridement, aggressive treatment with amphotericin B or posaconazole

Rhinocerebral zygomycoses (phycomycoses or mucormycoses) infections caused by nonseptate fungi (phylum Zygomycota, genera Rhizopus, Absidia, Mucor, Rhizomucor)

a fungus based on molecular biologic technique like ribotyping and DNA homology Obligate fungal organism not grown in vitro but extracellular, growing on surfactant layer affecting ability of oxygen to interact with lungs Trophozoites and larger cysts seen in alveoli by methenamine silver or calcofluor stained tissue Interstitial plasma cell pneumonitis happens in malnourished infants, transplant patients, patients on antineoplastic chemotherapy, patients on corticosteroid therapy. Ground glass appearance Lung is nonfunctional Treated with antineoplastic chemotherapy: preventing development, maturation, spread of neoplastic cells responsible for approx. one third of deaths in AIDs patients, morbidity and mortality when CD4+ counts decrease to less than 200/mm3, PCP lacks plasma cells in the alveolar spaces

Pneumocystis pneumonitis/pneumonia infections caused by Pneumocytis jiroveci (formerly Pneumocystis carinii)

often occurs in immunocompromised individuals but may also occur in those who are immunocompetent involves a variety of organs and systems, most notably, intestine, lung, kidney, brain, sinuses, muscle, and eyes. i.e.- 28-year-old female missionary from Mozambique who presented to our diagnostic laboratory complaining of nausea, lower abdominal pain, and frequent bowel movements.

Microsporidial enteritis Enterocytozoon bieneusi and Encephalitozoon intestinalis are associated with gastroenteritis, while Enc. hellem and Enc. cuniculi are associated with keratoconjunctivitis.

opportunistic mycoses associated with gastroenteritis stems from these fungi

Enterocytozoon bieneusi and Encephalitozoon intestinalis

opportunistic mycoses associated with keratoconjunctivitis

Enc. hellem and Enc. cuniculi

51. Which of the following are not correctly matched? a. Tinea corporis – hairy body parts b. Tinea capitis – scalp c. Tinea pedis – athlete’s foot d. Tinea barbae – beard e. Tinea cruris – jock itch

60. The fungus classically associated with erythematous nodules along the lymphatics on the extremities is: a. chromomycosis b. coccidioidomycosis c. mycetoma d. paracoccidioidomycosis e. Sporotrichosis

61. A student in a town near the Ohio River reports a headache, fever, nonproductive cough, and papular skin eruption. He has enjoyed the weekends exploring caves. The pathology from a skin biopsy showed small intracellular yeast forms with pseudocapsules. Which of the following is the most likely pathogen? a. Aspergillus fumigatus b. Coccidioides immitis c. Histoplasma capsulatum d. Paracoccidioides brasiliensis e. Sporothrix schenckii

63. A patient presents with paranasal swelling and bloody exudate from both his eyes and nares, and he is nearly comatose. Necrotic tissue in the nasal turbinates show nonseptate hyphae consistent with Rhizopus, Mucor, or Absidia (phylum Zygomycota, class Phycomycetes) What is the most likely compromising condition underlying this infection? (A) AIDS (B) Ketoacidotic diabetes (C) Neutropenia (D) B-cell defects (E) Chronic sinusitis BRS Ed.5th

64. A patient presents with a circular, itchy,inflamed skin lesion that is slightly raised; it is on his left side where his dog sleeps next to him.His dog has had some localized areas of hair loss. The patient has no systemic symptoms. What would you expect to find in a KOH of skin scrapings? (A) Clusters of yeastlike cells and short curved septate hyphae (B) Hyphae with little branching but possibly with some hyphae breaking up into arthroconidia (C) Filariform larvae (D) Budding yeasts with some pseudohyphae and true hyphae (E) Large budding yeast cells with broad bases on the buds and thick cell walls BRS Ed.5th

70. A patient has splotchy hypopigmentation on the chest and back with only slight itchiness. What is most likely to be seen on a KOH mount of the skin scraping? (A) Yeasts, pseudohyphae, and true hyphae (B) Filaments with lots of arthroconidia (C) Clusters of round fungal cells with short, curved, septate hyphae (D) Darkly pigmented, round cells with sharp interior septations (E) Cigar-shaped yeasts BRS Ed.5th

``` 71. A patient has a dry, scaly, erythematous penis. Skin scales stained with calcofluor white show fluorescent blue-white yeasts and a few pseudohyphae. What is the causative agent of this dermatophytic look-alike? (A) Candida (B) Trichosporon (C) Trichophyton (D) Malassezia (E) Microsporum BRS Ed.5th ```

``` 72. A patient who is a recent immigrant from a tropical, remote, rural area with no medical care is now working with a group of migrant crop harvesters. He has a large, raised, colored, cauliflower-like ankle lesion. Darkly pigmented, yeastlike sclerotic bodies are seen in the tissue biopsy. Which of the following is the most likely diagnosis? (A) Actinomycotic mycetoma (B) Chromoblastomycosis (C) Eumycotic mycetoma (D) Sporotrichosis (E) Tinea nigra BRS Ed.5th ```

Fungal Infections Flashcards

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