USMLE - Micro Mycology

Question 1

Systemic Mycoses Names Disease caused by it...Kind of organisms?TemperatureTreatment What might it be confused with?

Accepted Answer

Histoplasmosis, Blastomycosis, Coccidioidomycosis, Paracoccidioidomycosis
Can cause pneumonia and disseminate
Dimorphic fungi:
Cold (20) = mold. Heat (37) = yeast. Except for Coccidio which is a spherule in tissue (not yeast)
Fluconazole or Itraconazole for local infections. Amphotericin B for systemic infections
Can mimic TB (form granulomas) except no person-to-person transmission

Question 2

Histoplasmosis Presentation LocationVectors  Histo

Accepted Answer

Pneumonia Mississippi and Ohio River Valley Bird or bat droppings Macrophage filled with Histoplasma (smaller than RBCs)"Histo Hides in macs"

Question 3

BlastomycosisPresentationHistoLocation

Accepted Answer

Inflammatory lung disease and can disseminate to skin and boneForms granulomatous nodules. Broad-base budding (same size as RBCs)States east of Mississippi river and in Central America

Question 4

Coccidioidomycosis Presentation When do rates go up?HistoLocation

Accepted Answer

Pneumonia and meningitis. Can disseminate to bone and skin
Cases ↑ after earthquakes
Spherule filled with endospores (much larger than RBCs). At higher temps: Hyphae
Southwestern US and California
San Joaquin Valley or desert (desert bumps) - Valley Fever

Question 5

ParacoccidioidomycosisLocationHisto

Accepted Answer

Latin AmericaBudding yeast with Captain’s Wheel formation (much larger than RBCs)“Paracoccidioidomycosis parasails with the captain’s wheel all the way to Latin America”

Question 6

Tinea versicolor What is it caused by?Weapons Presentation HistoLocation where it occurs Treatment

Accepted Answer

Malassezia furfur - yeast fungiDegrades lipids and that produces acids that damage melanocytesHypo- or hyperpigmented patchesSpaghetti and meatball appearance on KOH prepHot, humid weatherTopical mconazole, Selenium sulfide (Selsun)

Question 7

Other Tinea Organisms that cause itWhat does it cause?Names with location of infection Presentation HistoLife cycle

Accepted Answer

Dermatophytes (Microsporum, Trichophyton, Epidermophyton)
Ringworm
Tinea pedis (foot), Tinea cruris (groin), Tinea corporis (ringworm on body), Tinea capitis (head, scalp), Tinea unguium (onychomycosis on fingernails)
Pruritic lesion with central clearing (ring)
Mold hyphae on KOH prep. Not dimorphic

Question 8

Candida albicans What is it?Who is susceptible? What does it cause?Treatment Histo

Accepted Answer

Opportunistic fungal infectionImmunocompromisedOral and esophageal thrush in Immunocompromised (neonates, steroids, diabetes, AIDS), Vulvovaginitis (diabetics, antibiotic use), Diaper rash, Endocarditis in IV drug users, Disseminated Candidiasis (to any organ), Chronic Mucocutaneous CandidiasisTopical azole for vaginal. Fluconazole or caspofungin for oral/esophageal. Fluconazole, amphotericin B or Caspofungin for systemicForms germ tubes at 37

Question 9

Aspergilus fumigatus What is it?Who is susceptible?What diseases does it cause?Weapons Life cycle  Histo

Accepted Answer

Opportunistic fungal infection of immunocompromised and those with chronic granulomatous disease
Allergic bronchopulmonary aspergillosis (w/ asthma or CF), Aspergillomas in lung cavities (after TB infection)
Aflatxins associated with HCC
Not dimorphic
Septate hyphae that branch at 45 deg angles. Conidiophore with radiating chains of spores
“A for Acute Angles in Aspergillus”

Question 10

Cryptococcus neoformans What is it?Diseases caused by it?Histo Life cycle? Where is it found?Transmission? Growth? Stains? Test? Kind of lesion?

Accepted Answer

Opportunistic fungal infectionCryptococcal meningitis, CrytpcoccosisHeavily encapsulated yeast (wide capsular halos). Unequal buddingNot dimorphic. Found in soil, pigeon droppings. Acquired through inhalation to the lungs with hematogenous dissemination to meningesCulture on Sabouraud’s agar. Stains with India inkLatex agglutination test detects polysaccharide capsular AgSoap bubble brain lesion

Question 11

Mucor and Rhizopus Species What is it?What do they cause?Who gets it?PathoPhysWhat doe they form?Presentation Histo

Accepted Answer

Opportunistic fungal infectionMucormycosisDKA and leukemic ptsProliferate in blood vessel walls when there is excess ketone and glucosePenetrate cribriform plate and enter brain forming Rhinocerebral, Frontal lobe abscessesHeadache, Facial pain, Black necrotic eschar on face. May have CN involvementIrregular broad nonseptate hyphae branching at wide angles

Question 12

Pneumocystis jirovecii What is it?Who is at risk?What does it cause?Transmission Presentation. XR. Diagnosis HistoTreatment

Accepted Answer

Opportunistic fungal infection (yeast)Immunosuppressed (AIDS)Pneumocystis pneumonia (PCP) - a diffuse interstitial pneumoniaInhaledAsymptomatic. Diffuse bilateral CXR appearanceLung biopsy or lavage. Disc-shaped yeast forms on methenamine silver stain of lung tissueTMP-SMX, Pentamidine, Dapsone. Start prophylaxis when CD4 drops below 200 in HIV pts

Question 13

Sporothrix schenckiiWhat is it? What does it cause?Life cycle Histo Where do they live? Transmission?Presentation Treatment

Accepted Answer

Opportunistic fungal infectionSporotrichosisDimorphic. Cigar shaped budding yeastLives on vegetationSpores traumatically introduced into skin by thornsLocal pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis) without systemic illnessItraconazole or Potassium iodide“Plant a rose in the pot” “Rose gardeners disease”

Term	Definition
Systemic Mycoses Names Disease caused by it... Kind of organisms? Temperature Treatment What might it be confused with?	Histoplasmosis, Blastomycosis, Coccidioidomycosis, Paracoccidioidomycosis Can cause pneumonia and disseminate Dimorphic fungi: Cold (20) = mold. Heat (37) = yeast. Except for Coccidio which is a spherule in tissue (not yeast) Fluconazole or Itraconazole for local infections. Amphotericin B for systemic infections Can mimic TB (form granulomas) except no person-to-person transmission
Histoplasmosis Presentation Location Vectors Histo	Pneumonia Mississippi and Ohio River Valley Bird or bat droppings Macrophage filled with Histoplasma (smaller than RBCs) "Histo Hides in macs"
Blastomycosis Presentation Histo Location	Inflammatory lung disease and can disseminate to skin and bone Forms granulomatous nodules. Broad-base budding (same size as RBCs) States east of Mississippi river and in Central America
Coccidioidomycosis Presentation When do rates go up? Histo Location	Pneumonia and meningitis. Can disseminate to bone and skin Cases ↑ after earthquakes Spherule filled with endospores (much larger than RBCs). At higher temps: Hyphae Southwestern US and California San Joaquin Valley or desert (desert bumps) - Valley Fever
Paracoccidioidomycosis Location Histo	Latin America Budding yeast with Captain’s Wheel formation (much larger than RBCs) “Paracoccidioidomycosis parasails with the captain’s wheel all the way to Latin America”
Tinea versicolor What is it caused by? Weapons Presentation Histo Location where it occurs Treatment	Malassezia furfur - yeast fungi Degrades lipids and that produces acids that damage melanocytes Hypo- or hyperpigmented patches Spaghetti and meatball appearance on KOH prep Hot, humid weather Topical mconazole, Selenium sulfide (Selsun)
Other Tinea Organisms that cause it What does it cause? Names with location of infection Presentation Histo Life cycle	Dermatophytes (Microsporum, Trichophyton, Epidermophyton) Ringworm Tinea pedis (foot), Tinea cruris (groin), Tinea corporis (ringworm on body), Tinea capitis (head, scalp), Tinea unguium (onychomycosis on fingernails) Pruritic lesion with central clearing (ring) Mold hyphae on KOH prep. Not dimorphic
Candida albicans What is it? Who is susceptible? What does it cause? Treatment Histo	Opportunistic fungal infection Immunocompromised Oral and esophageal thrush in Immunocompromised (neonates, steroids, diabetes, AIDS), Vulvovaginitis (diabetics, antibiotic use), Diaper rash, Endocarditis in IV drug users, Disseminated Candidiasis (to any organ), Chronic Mucocutaneous Candidiasis Topical azole for vaginal. Fluconazole or caspofungin for oral/esophageal. Fluconazole, amphotericin B or Caspofungin for systemic Forms germ tubes at 37
Aspergilus fumigatus What is it? Who is susceptible? What diseases does it cause? Weapons Life cycle Histo	Opportunistic fungal infection of immunocompromised and those with chronic granulomatous disease Allergic bronchopulmonary aspergillosis (w/ asthma or CF), Aspergillomas in lung cavities (after TB infection) Aflatxins associated with HCC Not dimorphic Septate hyphae that branch at 45 deg angles. Conidiophore with radiating chains of spores “A for Acute Angles in Aspergillus”
Cryptococcus neoformans What is it? Diseases caused by it? Histo Life cycle? Where is it found? Transmission? Growth? Stains? Test? Kind of lesion?	Opportunistic fungal infection Cryptococcal meningitis, Crytpcoccosis Heavily encapsulated yeast (wide capsular halos). Unequal budding Not dimorphic. Found in soil, pigeon droppings. Acquired through inhalation to the lungs with hematogenous dissemination to meninges Culture on Sabouraud’s agar. Stains with India ink Latex agglutination test detects polysaccharide capsular Ag Soap bubble brain lesion
Mucor and Rhizopus Species What is it? What do they cause? Who gets it? PathoPhys What doe they form? Presentation Histo	Opportunistic fungal infection Mucormycosis DKA and leukemic pts Proliferate in blood vessel walls when there is excess ketone and glucose Penetrate cribriform plate and enter brain forming Rhinocerebral, Frontal lobe abscesses Headache, Facial pain, Black necrotic eschar on face. May have CN involvement Irregular broad nonseptate hyphae branching at wide angles
Pneumocystis jirovecii What is it? Who is at risk? What does it cause? Transmission Presentation. XR. Diagnosis Histo Treatment	Opportunistic fungal infection (yeast) Immunosuppressed (AIDS) Pneumocystis pneumonia (PCP) - a diffuse interstitial pneumonia Inhaled Asymptomatic. Diffuse bilateral CXR appearance Lung biopsy or lavage. Disc-shaped yeast forms on methenamine silver stain of lung tissue TMP-SMX, Pentamidine, Dapsone. Start prophylaxis when CD4 drops below 200 in HIV pts
Sporothrix schenckii What is it? What does it cause? Life cycle Histo Where do they live? Transmission? Presentation Treatment	Opportunistic fungal infection Sporotrichosis Dimorphic. Cigar shaped budding yeast Lives on vegetation Spores traumatically introduced into skin by thorns Local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis) without systemic illness Itraconazole or Potassium iodide “Plant a rose in the pot” “Rose gardeners disease”

USMLE - Micro Mycology

Flash Cards

Spaced Repetition

Take Quiz

Systemic Mycoses
Names
Disease caused by it...
Kind of organisms?
Temperature
Treatment
What might it be confused with?

Key Terms

Related Flashcard Decks

Study Tips

Company

Explore

Study Tools