Medical Mycology III - Dimorphic Fungi

Question 1

Why did dimorphic fungi evolve?

Answer 1

Fungi were originally adapted to a cold, dark habitat. The bodies of animals are much warmer, so some fungi evolved to form a yeast form at warmer temperatures.

Question 2

Beaver dams have been implicated in _______________.

Answer 2

Blastomyces infection

Question 3

Dogs often get Blastomyces from _______________.

Answer 3

prairie dogs

Question 4

In a healthy person, Blastomyces can cause _____________.

Answer 4

infiltrative pneumonia

Question 5

Blastomyces most often gets into the body by ____________.

Answer 5

inhalation

Question 6

What disease can Blastomyces cause that is not covered in the Sketchy scene?

Answer 6

Cutaneous infection

Question 7

Blastomyces can form ___________ hyphae.

Answer 7

thin, septate

Question 8

Blastomyces divides in a _______________ manner.

Answer 8

broad-based

Question 9

_____________ prefers an arid climate.

Answer 9

Coccidioides

Question 10

The “classic” Coccidioides is __________.

Answer 10

C. immitis

Question 11

Lung cavitations and nodules are typical of ____________.

Answer 11

Coccidioidomycosis (often called “desert wind disease”)

Question 12

______________ are spheroid and very large.

Answer 12

Coccidioidal spherules (the tumbleweed much larger than the RBC sombrero)

Question 13

In general, laboratory culture of fungi grows the ____________ form.

Answer 13

cold, mold, spore-forming version

Question 14

Alternating arthroconidia are _____________.

Answer 14

hyphae that have acellular interruptions that are suggestive of Coccidioides

Question 15

Complement fixation predicts likelihood of ______________.

Answer 15

extrapulmonary Coccidioides

Question 16

______________ overlaps the geographical distribution of Blastomyces.

Answer 16

Histoplasma

Question 17

Question stems will commonly mention _____________ if they’re directing you to a diagnosis of Histoplasmosis.

Answer 17

caves (spelunking), chimneys (in which bats might have pooped), or chicken coops

Question 18

______________ pneumonia is a classic sign of Histoplasmosis.

Answer 18

Shotgun

Question 19

Blood cultures will not usually test positive even in fulminant ____________.

Answer 19

Histoplasmosis; antigen testing is more successful and quicker (like the red and yellow dripping stalactites!)

Question 20

What length of antibiotics is typical of UTI treatment?

Answer 20

3 days

Question 21

Although Sporothrix schenckii is found around the world, it is most common in _______________.

Answer 21

South America

Question 22

Uniquely among the infectious fungi, Sporothrix is _______________.

Answer 22

usually transmitted by direct inoculation (as opposed to the usual inhalation)

Question 23

Sporothrix is more common in _____________.

Answer 23

male adults and children of both sexes

Question 24

Although uncommon, Sporothrix can ______________.

Answer 24

disseminate to the bones, joints, lungs, and meninges

Question 25

True or false: Sporothrix can be detected through urine antigen screens.

Answer 25

False. There are no serologic tests for Sporothrix.

Question 26

What four treatments can be given in Sporotrichosis?

Answer 26

• KI
• Terbinafine
• Itraconazole
• Amphotericin B

Question 27

______________ is found only in Central and South America.

Answer 27

Paracoccidioides brasiliensis

Question 28

P. brasiliensis occurs most often in _______________ workers.

Answer 28

agricultural workers on coffee farms

Question 29

______________ seems to inhibit Paracoccidiodes.

Answer 29

Estrogen

Question 30

What is the classic triad of Paracoccidioides?

Answer 30

• Edentulous (bad dental caries)
• COPD
• Cervical lymphadenopathy

Question 31

Although treatment will annihilate Paracoccidioides, the _____________ will remain.

Answer 31

lung damage

Question 32

________________ localizes to SE Asia.

Answer 32

Taloramyces (aka Penicillium) marneffei

Question 33

T. marneffei is a ___________ fungi.

Answer 33

dimorphic

Question 34

Under microscopy, Penicillium and Taloramyces look like ________________.

Answer 34

skeleton hands

Question 35

What does this lecturer want you to know by the quote “Just because the water is calm doesn’t mean there are no crocodiles”?

Answer 35

In immunocompromised people, they might not have a fever or signs of infection but still have infection.

Question 36

Why does BMT predispose people to Aspergillus infection?

Answer 36

BMT makes people temporarily neutropenic, and neutrophils are needed to kill Aspergillus because it is catalase-positive.

Question 37

List the dimorphic fungi.

Answer 37

• Sporothrix schenckii
• Coccidioidomycosis
• Histoplasma
• Blastomyces
• Paracoccidioidomycosis

(“Some Can Have Both Phases”)

Question 38

____________ has a cottony macroscopic appearance.

Answer 38

Blastomyces

Question 39

The _____________ of Coccidioidomycosis are highly infectious.

Answer 39

arthroconidia

Question 40

The incubation period of _____________ is long –up to 20 years.

Answer 40

P. brasiliensis

Question 41

What is the best method for diagnosing an intracellular fungus?

Answer 41

Lysis-centrifugation culture

Question 42

What pathology does mucor cause in IV drug users?

Answer 42

Skin abscesses at the site of infection with infarctive necrosis

Question 43

The best way to treat a Candida UTI in an ICU patient is ________________.

Answer 43

removal of the catheter; medical treatment will usually just decrease the colony count, only for it to return soon after

Question 44

True or false: Cryptococcus only causes disease in the immunocompromised.

Answer 44

False. Healthy people can get lung lesions (particularly common in the northwest).