Hertz CIS Fungal infections

Question 1

Types of fungus

Answer 1

Superficial and cutaneous mycoses

Subcutaneous mycoses

Endemic mycoses

Opportunistic mycoses

Question 2

Superficial and cutaneous mycoses

Answer 2

are common and limited to the very superficial or keratinized layers of skin, hair, and nails.

Question 3

Subcutaneous mycoses

Answer 3

involve the skin, subcutane­ous tissues, and lymphatics and rarely disseminate systemically.

Question 4

Endemic mycoses

Answer 4

are caused by dimorphic fungi that can produce serious systemic illness in healthy individuals.

Question 5

Opportunistic mycoses

Answer 5

can cause life-threatening systemic diseases in individuals who are immunosuppressed or who carry implanted prosthetic devices or vascular catheters.

Question 6

Candidiasis

Answer 6

Most Candida infections originate when the normal commensal flora breach the skin or mucosal barriers

C. albicans, are the most frequent cause of human fungal infections

Question 7

what cells are important for protection against candida infection?

Answer 7

Neutrophils, macrophages and TH17 cells are important for protection against Candida infection

T helper cells are decreased in HIV and make us more susceptible to these types of organisms.

Question 8

important diagnostic clue of C. albicans

Answer 8

pseudohyphae- chain of budding yeast cells joined end to end at constrictions. Can be seen with yeast and hyphae together in the same tissue.

Question 9

Invasive candidiasis is caused by bloodborne dissemination of organisms to various tissues or organs, including…

Answer 9

(1) Renal abscesses
(2) Myocardial abscesses and endocarditis
(3) Brain microabscesses and meningitis
(4) Endophthalmitis (virtually any eye structure can be involved)
(5) Hepatic abscesses

Question 10

Cryptococcosis

Answer 10

C. neoformans and C. gattii, both of which grow as encapsulated yeasts.

while C. neoformans may cause meningoencephalitis in otherwise healthy individuals, it more frequently presents as an opportunistic infection in people with AIDS, leukemia, lymphoma, systemic lupus erythematosus, or sarcoidosis, as well as in immunosuppressed transplant recipients.

Many of these patients receive high-dose corticosteroids, a major risk factor for C. neoformans infection. Cryptococcus neoformans is present in the soil and in bird (particularly pigeon) droppings and infects people when it is inhaled

Question 11

AIDS with lung stuff, think

Answer 11

pneumocystis carinii

Question 12

How big is stuff that gets stuck in the lungs?

Answer 12

50 microns- upper airway
25 microns- bronchii
10 microns- gets to the alveoli

Question 13

if you hear pigeon, CNS, immunocompromised, think

Answer 13

cryptococcus. India ink preparation with the white blobs (capsule) around the bug.

Mucicarmine stains the capsule pink.

Question 14

The major lesions caused by cryptococcus are

Answer 14

in the CNS, involving the meninges, cortical gray matter, and basal nuclei

loves perivascular area

Question 15

soap bubble lesion in the brain refers to

Answer 15

cryptococcus

mucicarmine stain in a virchow-Robin perivascular space of the brain

Question 16

Aspergillus

Answer 16

is a ubiquitous mold that causes allergies (allergic bronchopulmonary aspergillosis) in otherwise healthy people and serious sinusitis, pneumonia, and invasive disease in immunocompromised individuals

Question 17

major conditions that predispose to aspergillus infection

Answer 17

neutropenia and use of corticosteroids. Aspergillus fumigatus is the most common pathogenic species of the fungus.

Question 18

45 degree angles of growth, septate, fruiting heads, are key words for

Answer 18

aspergillus

Question 19

aspergilloma

Answer 19

fungus ball

colonizes, walled off, minimal invasion of the tissues. Necrotizing. - often people have hemoptysis

Question 20

Right angle branching, no septae, wide and fat…?

Answer 20

zygomycosis (mucormycosis)

Buzz word: wet cigarette paper

history will usually involve being immunocompromised, including diabetes mellitus, iron overload, corticosteroid use, etc.

Question 21

what bugs love iron?

Answer 21

haemophilus (bacteria) and mucormycosis (fungus)

Question 22

di morphic fungi

Answer 22

2 different morphologies: one at room temperature (mold) and one at body temperature (yeast farms)

The medically important dimorphic fungi are blastomyces, histoplasma, and coccidioidomyces

Question 23

Chronic pneumonia– start by thinking

Answer 23

most often a localized lesion in the immunocompetent patient, with or without regional lymph node involvement. Typically, the inflammatory reaction is granulomatous, and is caused by bacteria (e.g., M. tuberculosis) or fungi (e.g., Histoplasma capsulatum)

Question 24

Histoplasma capsulatum

Answer 24

is acquired by inhalation of dust particles from soil contaminated with bird or bat droppings that contain small spores (microconidia), the infectious form of the fungus. It is endemic along the Ohio and ***Mississippi rivers and the Caribbean

Question 25

coin lesion in lung that looks like tree bark (calcified spherical nodule)

Answer 25

burned out caseating granuloma

histoplasmosis (do a silver stain to make sure)

Question 26

rank order in size the 3 things that get stuck in the lungs

Answer 26

tiniest: histo. Easily gets in alveoli
next: blasto– tends to get stuck higher
biggest: coccidio, but it can send endospores down into the alveoli

Question 27

The diagnosis of histoplasmosis is established by

Answer 27

culture or identification of the fungus in tissue lesions. In addition, serologic tests for antibodies and antigen are also available. Antigen detection in body fluids is most useful in the early stages, because antibodies are formed 2 to 6 weeks after infection

Question 28

Blastomyces dermatitidis

Answer 28

is a soil-inhabiting dimorphic fungus.

It causes disease in the central and southeastern United States; infection also occurs in Canada, Mexico, the Middle East, Africa, and India.

There are three clinical forms: pulmonary blastomycosis, disseminated blastomycosis, and a rare primary cutaneous form that results from direct inoculation of organisms into the skin

Broad-based buds.

Question 29

after inhalining spores of Coccidioidomycosis

Answer 29

Almost everyone who inhales the spores of Coccidioides immitis becomes infected and develops a delayed-type hypersensitivity reaction to the fungus.

Indeed, more than 80% of people in endemic areas of the southwestern and western United States and in Mexico have a positive skin test reaction.

One reason for the infectivity of C. immitis is that infective arthroconidia, when ingested by alveolar macrophages, block fusion of the phagosome and lysosome and so resist intracellular killing

Question 30

if it’s a petri dish taped shut it’s a clue that it’s

Answer 30

coccidioides

Question 31

people who get infected with histoplasma and show symptoms…

Answer 31

But 10% of infected people develop lung lesions, fever, cough, and pleuritic pains, accompanied by erythema nodosum or erythema multiforme (the San Joaquin Valley fever complex).

Less than 1% of people develop disseminated C. immitis infection, which frequently involves the skin and meninges

Question 32

landing a helicopter in arizona, get a fever afterward

Answer 32

location and history tell you coccidioides because of soil blowing around and location.

Question 33

buzz words to think about

Answer 33

cryptococcs- AIDS, soil, bird droppings
candida- pseudohyphae
mucormycosis- diabetes
blasto- broad-based