skin 11: subQ fungal infections

Question 1

all agents of subQ fungal infections

Answer 1

Sporotrichosis, Mycetoma, Lobomycosis, Chromoblastomycosis, Phaeomycotic cysts

Question 2

source for these subQ agents ??
mode of entry??
Only ?? can display visceral organ involvement.

Answer 2

Plant material (splinters, thorns, etc)
implantation
sporotrichosis

Question 3

Sporotrichosis agent

Answer 3

Sporothrix schenckii, a thermally dimorphic fungus

Question 4

Sporotrichosis distribution?

risk factors??

Answer 4

worldwide
contact with plant material and subsequent implantation of the organism through a trauma wound (e.g. rose thorn, wood splinter).

Question 5

Sporotrichosis is usually a ??

What can occur in individuals who are immunosuppressed??

Answer 5

chronic infection characterized by nodular lesions of cutaneous or subcutaneous tissues and adjacent lymphatics that suppurate, ulcerate and drain (lymphocutaneous or gummatous sporotrichosis).

Visceral organ involvement (disseminated form)

Question 6

Sporotrichosis px

Answer 6

Good for lymphocutaneous, fixed cutaneous and mucocutaneous forms.
Grave for disseminated form

Question 7

Sporotrichosis dx

Answer 7

Direct microscopic examination of pus, exudate, biopsy material and aspirates is best, and easily achieved with a fluorescent antibody staining technique. The organism is dimorphic, thus cultured at room temperature (25oC) and at 37oC.
also Sporotrichin skin test.

Question 8

Sporotrichin skin test:

what is it used for?

Answer 8

A DTH response is positively associated with less severe disease. Not useful for diagnosis.
Serological tests against the yeast cell antigen are used to monitor the course of disease and effectiveness of treatment.

Question 9

Sporotrichosis ddx

Answer 9

nocardiosis,
cutaneous leishmaniasis and
atypical mycobacterial infection, especially Mycobacterium marinum (fish tank cellulitis)

Question 10

Sporotrichosis tx

Answer 10

Itraconazole;
Amphotericin B in AIDS pts (ensure it does not become systemic)
heat about 39oC 3-4x/day on affected extremity (slows progression of lesion)

Question 11

Mycetoma is an ??

Answer 11

infectious process with tumefaction (looks like a tumor), usually involving the foot or hand, caused by organisms that stimulate grain formation and eventually drain through sinus tracts in the skin. (sounds like actinomycosis)

Question 12

Mycetoma grains comprised of ??
though to represent ??

referred to as the ??

Answer 12

the agent stuck in a matrix;

a precipitate of Ag-Ab complexes and Splendore-Hoeppli material deposition of eosinophilic material around the microorganisms

Splendore-Hoeppli phenomenon

Question 13

2 groups of orgs cause mycetomas: ??

Answer 13

a variety of bac and fungi (including Actinomyces israelii)

Question 14

mycetoma is endemic in ??

gender?? age??

Answer 14

the tropics and subtropics
(between the Tropics of Cancer and Capricorn).

More common in men than women, particularly those aged 20 to 50.

Question 15

mycetoma generally presents as ??
and may persist ??
2/3 arise on the ??

Answer 15

a single lesion on an exposed site
for years
foot. (Madura foot)

Question 16

mycetoma starts as a ??
It grows slowly but eventually involves ??
what happens to the middle of the lesion??

Answer 16

small hard painless lump under the skin.
involves underlying muscles and bones.
The middle of the lesion caves in ulcerates and discharges pus, which contains grains.

Question 17

mycetoma lesions eventually develops ??

Answer 17

sinus tracts (holes) which also discharge pus and grains. 
The surface skin is scarred and pale. Considerable deformity often makes it difficult to walk; may cause no discomfort but it often itches or burns.

Question 18

mycetoma complications

visceral involvement?

Answer 18

Secondary bacterial infection is common.

There is contiguous bone involvement, but visceral dissemination does not occur.

Question 19

?? is a synonym for mycetoma of the foot only.

Answer 19

Madura foot

Question 20

The diagnosis of mycetoma depends on ??

Answer 20

identifying grains. These are obtained using a needle and syringe to extract material from a soft part of the lesion under the skin or by collecting pus. Occasionally a skin biopsy is necessary.

Question 21

mycetoma ddx

Answer 21

Chromoblastomycosis;
Bacterial infections such as osteomyelitis, atypical
mycobacterium infection, tuberculosis, leprosy and syphilis

Question 22

mycetoma tx

Answer 22

Prolonged treatment at high dosage is required because of poor penetration into the area of cyst and abscess formation, and even then, surgical debridement and often amputation are necessary.

Question 23

Lobomycosis (Lobo’s Disease) agent

Answer 23

Loboa loboi

Question 24

most Lobomycosis infections are acquired where geographically??

Answer 24

South and Central America

Question 25

Lobomycosis Clinical Manifestations

Answer 25

An extremely indolent, chronic, subcutaneous infection that usually begins as well circumscribed, indurated, asymptomatic keloidal nodules that develop into slowly growing tumors of the dermis, that present smooth, verrucoid or ulcerated surfaces.

Question 26

Chromoblastomycosis (Chromomycosis) agents

Answer 26

several species of pigmented fungi.

Question 27

Chromomycosis occurs where geographically??

Answer 27

worldwide

Question 28

Chromoblastomycosis clinical manifestations

Answer 28

A localized chronic infection of the subcutaneous tissues
characterized by raised lesions that may present a cauliflower-like appearance.
Over years, lesions enlarge to involve entire extremity.

Question 29

Chromomycosis tx

Answer 29

antimycotic agents and surgery

Question 30

Phaeomycotic cyst: Following implantation of the organism, what develops??

Answer 30

a well-circumscribed subcutaneous abscess with surrounding cyst

Question 31

Phaeomycosis occurs where geographically?? and may be caused by ??

Answer 31

worldwide

over 30 different agents.