MYCOLOGY

Question 1

Malassezia furfur - Pathogenesis

Answer 1

Causes superficial infection by producing azelaic acid and altering skin pigmentation.

Question 2

Malassezia furfur - Clinical Features

Answer 2

Hypo- or hyperpigmented macules on the chest, back, or arms (Tinea versicolor).

Question 3

Malassezia furfur - Diagnosis

Answer 3

KOH prep shows ‘spaghetti and meatballs’ appearance (yeast and hyphae).

Question 4

Malassezia furfur - Treatment

Answer 4

Topical azoles or selenium sulfide shampoo.

Question 5

Trichophyton, Microsporum, Epidermophyton - Pathogenesis

Answer 5

Infect keratinized tissues (stratum corneum, hair, nails) and provoke inflammatory response.

Question 6

Trichophyton, Microsporum, Epidermophyton - Clinical Features

Answer 6

Tinea infections such as athlete’s foot (Tinea pedis), ringworm (Tinea corporis), and nail infections (Tinea unguium).

Question 7

Trichophyton, Microsporum, Epidermophyton - Diagnosis

Answer 7

Wood’s lamp for Microsporum; KOH prep reveals segmented hyphae.

Question 8

Trichophyton, Microsporum, Epidermophyton - Treatment

Answer 8

Topical or oral antifungals (e.g., terbinafine, griseofulvin).

Question 9

Sporothrix schenckii - Pathogenesis

Answer 9

Dimorphic fungus enters via skin trauma, spreading along lymphatic channels.

Question 10

Sporothrix schenckii - Clinical Features

Answer 10

Painless nodules and ulcers along lymphatic channels (Sporotrichosis, ‘rose gardener’s disease’).

Question 11

Sporothrix schenckii - Diagnosis

Answer 11

Culture showing dimorphic fungus; cigar-shaped yeast in tissue.

Question 12

Sporothrix schenckii - Treatment

Answer 12

Oral itraconazole or potassium iodide (in rare cases).

Question 13

Chromoblastomycosis - Pathogenesis

Answer 13

Trauma introduces fungi into subcutaneous tissues, leading to chronic infection.

Question 14

Chromoblastomycosis - Clinical Features

Answer 14

Warty, verrucous lesions with a slow progression, primarily on the lower limbs.

Question 15

Chromoblastomycosis - Diagnosis

Answer 15

KOH prep shows pigmented, ‘copper penny’ fungal cells.

Question 16

Chromoblastomycosis - Treatment

Answer 16

Itraconazole, terbinafine, or surgical excision for severe cases.

Question 17

Mycetoma - Pathogenesis

Answer 17

Chronic subcutaneous infection caused by fungal or bacterial agents (e.g., Madurella spp.).

Question 18

Mycetoma - Clinical Features

Answer 18

Swollen lesion with draining sinuses containing ‘grains’ of fungi or bacteria.

Question 19

Mycetoma - Diagnosis

Answer 19

Microscopy of grains; imaging for extent of infection.

Question 20

Mycetoma - Treatment

Answer 20

Antifungals (e.g., itraconazole) or surgery in advanced cases.

Question 21

Histoplasma capsulatum - Pathogenesis

Answer 21

Inhalation of spores from bird or bat droppings, leading to intracellular infection in macrophages.

Question 22

Histoplasma capsulatum - Clinical Features

Answer 22

Flu-like symptoms, hepatosplenomegaly, and granulomas in disseminated disease.

Question 23

Histoplasma capsulatum - Diagnosis

Answer 23

Urine antigen test; microscopy shows intracellular yeast in macrophages.

Question 24

Histoplasma capsulatum - Treatment

Answer 24

Itraconazole for mild cases; amphotericin B for severe disease.

Question 25

Blastomyces dermatitidis - Pathogenesis

Answer 25

Inhalation of spores; spreads to skin and bones in disseminated disease.

Question 26

Blastomyces dermatitidis - Clinical Features

Answer 26

Pulmonary symptoms, verrucous skin lesions, and bone pain in disseminated disease.

Question 27

Blastomyces dermatitidis - Diagnosis

Answer 27

Microscopy reveals broad-based budding yeast; culture confirms.

Question 28

Blastomyces dermatitidis - Treatment

Answer 28

Itraconazole for mild disease; amphotericin B for severe cases.

Question 29

Coccidioides immitis/posadasii - Pathogenesis

Answer 29

Inhalation of arthroconidia from soil leads to granulomatous lung disease.

Question 30

Coccidioides immitis/posadasii - Clinical Features

Answer 30

Valley fever: fever, cough, and erythema nodosum; meningitis in severe cases.

Question 31

Coccidioides immitis/posadasii - Diagnosis

Answer 31

Spherules with endospores in tissue; serology for antibodies.

Question 32

Coccidioides immitis/posadasii - Treatment

Answer 32

Fluconazole or itraconazole; amphotericin B for severe cases.

Question 33

Paracoccidioides brasiliensis - Pathogenesis

Answer 33

Inhalation of spores; disseminates to mucous membranes and skin.

Question 34

Paracoccidioides brasiliensis - Clinical Features

Answer 34

Mucocutaneous ulcers, lymphadenopathy, and pulmonary symptoms.

Question 35

Paracoccidioides brasiliensis - Diagnosis

Answer 35

Microscopy shows 'pilot's wheel' or 'Mickey Mouse' yeast.

Question 36

Paracoccidioides brasiliensis - Treatment

Answer 36

Itraconazole for mild cases; amphotericin B for severe cases.

Question 37

Candida albicans - Pathogenesis

Answer 37

Normal flora that overgrows in immunocompromised states, forming pseudohyphae.

Question 38

Candida albicans - Clinical Features

Answer 38

Oral thrush, vulvovaginitis, esophagitis, diaper rash, or disseminated candidiasis.

Question 39

Candida albicans - Diagnosis

Answer 39

KOH prep reveals budding yeast and pseudohyphae; culture confirms.

Question 40

Candida albicans - Treatment

Answer 40

Fluconazole for localized infections; echinocandins or amphotericin B for systemic disease.

Question 41

Cryptococcus neoformans - Pathogenesis

Answer 41

Inhalation of encapsulated yeast from pigeon droppings; causes CNS infection in immunocompromised.

Question 42

Cryptococcus neoformans - Clinical Features

Answer 42

Meningitis, fever, headache, and altered mental status.

Question 43

Cryptococcus neoformans - Diagnosis

Answer 43

India ink stain reveals encapsulated yeast; cryptococcal antigen test.

Question 44

Cryptococcus neoformans - Treatment

Answer 44

Amphotericin B with flucytosine, followed by fluconazole.

Question 45

Aspergillus spp. - Pathogenesis

Answer 45

Inhalation of spores; causes allergic, invasive, or chronic infections depending on immune status.

Question 46

Aspergillus spp. - Clinical Features

Answer 46

Allergic bronchopulmonary aspergillosis, aspergillomas (fungus balls), or invasive aspergillosis in neutropenic patients.

Question 47

Aspergillus spp. - Diagnosis

Answer 47

Galactomannan antigen test; hyphae show acute-angle branching in tissue.

Question 48

Aspergillus spp. - Treatment

Answer 48

Voriconazole or amphotericin B; surgical resection for aspergillomas.

Question 49

Mucor and Rhizopus spp. - Pathogenesis

Answer 49

Inhalation of spores causes angioinvasion, particularly in diabetics and immunocompromised.

Question 50

Mucor and Rhizopus spp. - Clinical Features

Answer 50

Rhinocerebral mucormycosis: necrosis of nasal tissues, palate, and brain.

Question 51

Mucor and Rhizopus spp. - Diagnosis

Answer 51

Histology shows broad, nonseptate hyphae with right-angle branching.

Question 52

Mucor and Rhizopus spp. - Treatment

Answer 52

Amphotericin B and surgical debridement.

Question 53

Pneumocystis jirovecii - Pathogenesis

Answer 53

Causes pneumonia in immunocompromised patients (e.g., HIV/AIDS).

Question 54

Pneumocystis jirovecii - Clinical Features

Answer 54

Progressive dyspnea, hypoxia, and bilateral ground-glass opacities on imaging.

Question 55

Pneumocystis jirovecii - Diagnosis

Answer 55

Silver stain shows cysts; PCR or antigen detection.

Question 56

Pneumocystis jirovecii - Treatment

Answer 56

Trimethoprim-sulfamethoxazole (TMP-SMX).