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Week 5 of Micro TA presentation > Opportunistic Mycoses, Subcutaneous Mycoses, Superficial Dermatophytes > Flashcards

Opportunistic Mycoses, Subcutaneous Mycoses, Superficial Dermatophytes Flashcards

1
Q

What type of patients are at risk for opportunistic mycoses

A 
HIV/AIDS
Cancer (e.g., leukemia)
Diabetes
Immunosuppression
-->Post-transplant
-->Corticosteroids
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2
Q

List of opportunistic mycoses

A 
Candida Albicans
Aspergillus
Cryptococcus Neoformans
Zygomycetes (mucor/rhizopus) 
Pneumocystis jiroveci (PCP)
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3
Q

Morphology of candida albicans

A

Dimorphic: Budding yeast (pseudohyphae that don’t branch); germ tubes

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4
Q

Clinical presentation of candida albicans in a normal host

A
  • Vulvovaginal candidasis: “yeast infection” (think post antibiotic treatment)- White and Curdlike
  • Cutaneous: Diaper Rash in Babies, Skin fold infections (intertriginous areas) in obese patients and diabetics, Nail plate infections
  • Esophagus: Candida esophagitis (oral Thrush) mostly immunocompromised patients, but also occurs in Diabetics and people on chronic steroids (asthma and COPD)
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5
Q

oral thrush vs oral hairy leukemia

A

Opportunist infectionss of candidal oral thrush (dorsal surface of tongue) and EBV oral hairy leukoplakia (lateral surfaces of tongue).

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6
Q

Diagnosis of candida albicans

A

KOH test preformed on direct biopsys (can visualize Germ tube), blood culture

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7
Q

Epidemiology of candida albicans

A

Women (esp. post-abx); immunocompromised; commensal organism

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8
Q

Clinical presentation of candida albicans in an immunocompromised host

A

Immunocompromised Host (Cell mediated immunity)-> Think Neutropenia

  • Mucocutaneous: Oral Thrush in AIDS, Transplant, chemotherapy patients
  • Systemic Infection: Can seed almost any organ! (Catheters –> candidemia, parenteral nutrition, broad spectrum antibiotics are risk factors and can occur in immunocompetent as well as immunosuppressed)
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9
Q

Aspergillus morphology

A

Spore-bearing, thin septate hyphae, acute-angle branching. Fruiting head may be seen under lactophenol blue stain.
Acute Angle Aspergillus. 45 degree branching.
Right angle branching: Compare morphology with zygomycetes (mucor/rhizopus)

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10
Q

Virulence factors aspergillus

A

Proteases, toxins (aflatoxin)

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11
Q

Clinical presentation of aspergillus

A

Non-immunocompromised:
Allergic bronchopulmonary aspergillosis (ABPA) (Asthma or CF);
aspergilloma (non-invasive fungus ball in preformed/TB lung cavities);

In immunocompromised:

  • -> invasive pulmonary, systemic dz (neutropenics); Angioinvasive –> HEMOPYTISIS (coughing up blood)
  • -> primary cutaneous infections; hematogenous spread

“Aspergillus = Acute Angle, Aspergilloma, Angioinvasion, ABPA”

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12
Q

Diagnosis of aspergillus

A

Biopsy, culture, lactophenol blue staining

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13
Q

Epidemiology of aspergillus

A 
Immunocompromised hosts. Commonly found in the environment.
#1 most common invasive mold in the world
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14
Q

Treatment of aspergillus

A

Voriconazole, Amphotericin B. Immune reconstitution important for recovery.

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15
Q

Cryptococcus Neoformans morphology

A

Monomorphic, Encapsulated yeast

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16
Q

Cryptococcus Neoformans virulence factors

A

Capsule (evade phagocytosis, deplete complement), phenotypic switching (change in capsule, cell wall), melanin (antioxidant, inhibit antifungal & Ab-mediated phagocytosis)

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17
Q

Cryptococcus Neoformans diagnosis

A

PAS & silver stain, INDIA INK ON CSF (Halo/soap bubbles), Serology, Latex agglutination (is more specific than serology)

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18
Q

Cryptococcus Neoformans epidemiology

A

Inhaled; Environmental (soil, pigeon droppings); immunocompromised (AIDS/defects in cellular immunity, transplant, pregnancy)

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19
Q

Cryptococcus Neoformans treatment

A

Amphotericin B – drug of choice for cryptococcal meningitis +/- flucytosine

Fluconazole – mild to moderate pulmonary cryptococcosis; maintenance therapy for cryptococcal meningitis/should avoid using during first trimester of pregnancy

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20
Q

Cryptococcus Neoformans clinical presentation

A

Respiratory (main route of entry), dissemination, meningitis (immunocompromised); may be asymptomatic

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21
Q

Zygomycetes (mucor/rhizopus) morphology

A

Wide, non-septate, ribbon-like hyphae with wide (right-angle) branching (vs acute branching of aspergillus).
Genera include Rhizopus (> 98% of cases) and Mucor

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22
Q

Zygomycetes (mucor/rhizopus) virulence factors

A

Have ketone reductase, an enzyme that allows them to thrive in high glucose, acidic conditions. Spore-forming. Able to ANGIOINVADE.

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23
Q

Zygomycetes (mucor/rhizopus) clinical presentation

A

Mucormycosis: angioinvasion  brain  tissue destruction leading to necrosis;
Primary cutaneous skin infections (BLACK NECROTIC ESCHAR) from direct inoculation

Common Clinical: Rhinocerebral zygomycosis-> Direct infection from airborne spores in the paranasal sinuses-> Black Nasal discharge (Black necrosis)

24
Q

Zygomycetes (mucor/rhizopus) epidemiology

A

IMMUNOCOMPROMISED hosts, associated strongly with DIABETES (hyperglycemia) and DKA, Deferoxamine therapy (Fe chelator; used by Rhizopus as siderophore), NEUTROPENIA, and bone marrow transplants

Cutaneous infections may follow surgery, burn wounds, trauma/ have been associated with Non-sterile bandages

25
Q

Zygomycetes (mucor/rhizopus) treatment

A

Surgical debridement is key, Amphotericin B, Posaconazole

26
Q

Pneumocystis jiroveci (PCP) morphology

A

Cup shaped fungi, “crushed ping-pong ball”

27
Q

Pneumocystis jiroveci (PCP) diagnosis

A

Methenamine Silver stain or Direct Fluorescent Antibody of sample – sputum or bronchiolar lavage
Cannot be grown in culture

28
Q

Pneumocystis jiroveci (PCP) virulence factors

A

Attachment to pulmonary epithelial cells

29
Q

Pneumocystis jiroveci (PCP) clinical presentation

A

Diffuse interstitial pneumonia with plasma cell infiltrates, hypoxemia (low pO2); CXR show diffuse/patchy bilateral, alveolar infiltrates – “ground glass” appearance. Asymptomatic in immunocompetent.

30
Q

Pneumocystis jiroveci (PCP) epidemiology

A

Immunocompromised hosts. Most common opportunistic infection in AIDS patients in US (CD4+

31
Q

Pneumocystis jiroveci (PCP) treatment and side effects

A

TMP-SMX (also used as prophylaxis in patients with CD4+

32
Q

Most common human fungal infections

A
  • Tinea cruris is pruritic infection of groin.

- Pityriasis versicolor is a superficial dermatophyte infection characterized by hypo or hyperpigmentation.

33
Q

What causes athlete’s foot/ what is the not common name of athlete’s foot?

A

Various topical dermatophytes. Tinea pedis.

34
Q

Diagnosis of athlete’s foot?

A

Inspection

35
Q

Treatment of athlete’s foot?

A

Topical antifungals (miconazole, tolnaftate)

36
Q

What causes nail fungus/what is medical term for nail fungus?

A

Trichophyton rubrum.

Fungal onychomycosis .

37
Q

Diagnosis of nail fungus

A

Inspection

38
Q

Treatment of nail fungus

A

Oral terbinafine (resistant to topicals)

39
Q

What causes ringworm, what is the medical term for ringworm

A

Various topical dermatophytes, tinea corporis

40
Q

Diagnosis of ringworm

A

Inspection

41
Q

Treatment of ringworm

A

Topical antifunguls

42
Q

hypo/hyperpigmentation, what is the cause and medical term

A

Cause: Malassezia furfur.

medical term: Pityriasis versicolor

43
Q

Diagnosis of Pityriasis versicolor

A

Scraping stained with KOH shows

yeast and hyphal forms (“spaghetti & meatballs”)

44
Q

Treatment of pityriasis versicolor

A

Topical Antifungals

45
Q

Superficial Dermatophytes

A

Trichophyton, Malassezia

46
Q

Subcutaneous Mycoses

A

Sporothrix, Madurella

47
Q

Madurella Grisea clinical

A

Chronic, slowly progressing ulcerative lesions on the foot . Subcutaneous infection caused by various species of fungi including Madurella mycetomatis and Madurella grisea. May see coarse black fungal granules in discharge

48
Q

Madurella Grisea pathogenesis

A

Found in the soil, enters through abrasions in the skin.

49
Q

Madurella Grisea diagnosis

A

Biopsy

50
Q

Madurella Grisea epidemiology

A

Farmers, People who don’t wear shoes.

51
Q

Madurella Grisea treatment

A

Surgical debridement, amputation, voriconazole, posaconazole

52
Q

Sporothrix schenckii morphology

A

Dimorphic, cigar-shaped, budding yeast.

53
Q

Sporothrix schenckii clinical

A

Sporotrichosis – local pustules and ulcers – spreads along draining lymph nodes (skip lesions); ascending lymphangitis; little to no systemic illness.

54
Q

Sporothrix schenckii diagnosis

A

Biopsy, culture.

55
Q

Sporothrix schenckii epidemiology

A

Lives on vegetation. Associated with gardening (particularly rose thorns). Rose gardener’s disease.

56
Q

Sporothrix schenckii treatment

A

Itraconazole.

57
Q

Sporothrix schenckii pathogenesis

A

Inoculation occurs in distal extremity with lymphangitic spread characteristically up arm.

Week 5 of Micro TA presentation (4 decks)

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