FUNGI

Question 1

Produces the carcinogen aflatoxin and is a common contaminant of moldy nuts and grains

Answer 1

Aspergillus favus

-aflatoxins contribute to the development of HEPATOCELLULAR CARCINOMA and act SYNERGISTICALLY WITH HBV to promote carcinogenesis

Question 2

Proliferation of this organism within the lung causes a “fungus ball” that must be removed surgically

Answer 2

Aspergillus fumigatus

-microscopically, the organism grows as SEPTATE HYPHAE, branching at 45 DEGREE ANGLES

Question 3

Although an opportunistic mycosis, it can cause hypersensitivity pneumonitis such as Farmer’s lung

Answer 3

Aspergillus fumigatus

-resulting from inhalation of MOLDY HAY

Question 4

Systemic mycosis that begins as lower respiratory tract infection and may disseminate to cause warty-like skin lesions

Answer 4

Blastomyces dermatitidis

-results in GRANULOMATOUS LUNG LESIONS SIMILAR TO TUBERCULOSIS; may also result in skeletal and genitourinary manifestations

Question 5

Systemic mycosis endemic to the southeastern US

Answer 5

Blastomyces dermatitidis

-fungi appears in infected tissue as yeast with BROAD-BASED BUDDING

Question 6

Causes a cottage cheese-like vaginal discharge

Answer 6

Candida albicans

-predisposing factors include IMMUNOSUPPRESSION, DIABETES, obesity, and the use of BROAD SPECTRUM ABX

Question 7

Causes white curd-like patches on the mucocutaneous membranes of the mouth and extend downward to cause esophagitis in immunocompromised patients

Answer 7

Candida albicans

-in addition to causing THRUSH, C. albicans is a common cause of TINEA UNGUIUM [fungal infection of nails] and DIAPER RASH

Question 8

Most common mycotic pathogen

Answer 8

Candida albicans

-although a YEAST, it can form PSEUDOHYPHAE in infected tissue and form characteristic GERM TUBES AT 37 DEGREES CELSIUS under lab conditions

Question 9

Systemic mycosis endemic to the San Joaquin Valley in southern California

Answer 9

Coccidioides immitis

-causes “VALLEY FEVER” characterized by arthralgias, cough, and fever

Question 10

Found within infected tissue as spherules that rupture to release endospores

Answer 10

Coccidioides immitis

-dimorphic fungi with contraction of infection by INHALATION OF ARTHROSPORES in the sand and soil

Question 11

The only mycotic pathogen with a capsule

Answer 11

Cryptococcus neoformans

-visualized with an INDIA INK TEST; capsule EXCLUDES ink, providing CONTRAST

Question 12

Causes meningitis in patients with underlying immunodeficiency, especially AIDS

Answer 12

Cryptococcus neoformans

-associated with PIGEON DROPPINGS, this fungus grows within the Virchow-Robin vascular spaces of the brain, resulting in “SOAP BUBBLE LESIONS”

Question 13

Causes cutaneous infections such as tinea corporis, tinea cruris (jock itch), and tinea pedis (athlete’s foot)

Answer 13

Dermatophytes

-typically caused by dermatophytes of the genera Trichophyton spp. and result in scaly hypo- or hyperpigmented ANNULAR PRURITIC LESIONS

Question 14

Associated with the inhalation of spores from bird or bat droppings in the Ohio and Mississippi river valley

Answer 14

Histoplasma capsulatum

-histologically characterized by MACROPHAGES STUFFED WITH NUMEROUS YEAST CELLS

Question 15

Most common pulmonary mycotic infection with symptoms ranging from asymptomatic to tuberculosis-like symptoms

Answer 15

Histoplasma capsulatum

-in immunocompetent individuals, infection often resolves, with CALCIFICATION OF HILAR LYMPH NODES

Question 16

Causes tinea versicolor, which manifests as patches of hyper- and hypopigmentation on the trunk

Answer 16

Malassezia furfur

-found in skin scales and has a characteristic SPAGHETTI AND MEATBALLS APPEARANCE [yeast clusters and short, curved septate hyphae]

Question 17

Most common cause of tinea capitis, ringworm of the scalp

Answer 17

Microsporum canis

-common in PREPUBESCENT CHILDREN WITH PETS; the natural inhibitor of Microsporum spp. growth, UNDECYLENIC ACID, is produced in the sebum of postpubertal individuals

Question 18

Results in rhinocerebral disease, primarily in patients with diabetic ketoacidosis or leukemia

Answer 18

Mucor and Rhizopus species

-distinct from other human fungal pathogens in that these species cause disease in their SEXUAL LIFE CYCLE and display NONSEPTATE HYPHAE BRANCHING AT 90 DEGREE ANGLES OR WIDER

Question 19

This organism grows as multiple budding yeasts that appear as “captain’s wheel” and causes disease almost exclusively in men

Answer 19

Paracoccidioides braziliense

-this GRANULOMATOUS LUNG DISEASE occurs primarily in CENTRAL AND SOUTH AMERICA, with >90% of cases seen in males

Question 20

Causes an alveolar pneumonia, typically in AIDS patients

Answer 20

Pneumocystis carinii

-previously thought to be a protozoa, this fungus causes a FOAMY, AMORPHOUS ALVEOLAR EXUDATE AND is seen as CUP or BOAT-SHAPED CYSTS upon staining with SILVER METHENAMINE

Question 21

Causes the most common subcutaneous mycosis, Rose handler’s disease

Answer 21

Sporothrix schenckii

-transmitted by the prick of a contaminated THORN; treated with dilute solution of POTASSIUM IODIDE IN MILK

Question 22

Produces a toxin that results in liver damage upon ingestion of wild mushrooms

Answer 22

Amanita species

-ingestion may result in life-threatening FULMINANT HEPATITIS, requiring liver transplant