Mycoses Flashcards
1
Q
systemic mycoses - appearance
A
all dimorphic fungi
(EXCEPT COCCIDIOIDOMYCOSIS –> SPHERULE - NOT YEAST IN TISSUE)
cold (20c) –> mold
heat (37c) –> yeast
2
Q
systemic mycoses -treatment . they can mimic
A
local infection: fluconazole or intraconazole
systemic infection: amphotericin B
they can mimic: TB (granouloma formation)
except, unlike TB, no peroson to person transmission
3
Q
systemic mycosis - area (map)
A
- Histoplasmosis –> Mississippi and Ohio River valleys
- Blastomycosis –> Eastern US and Central America
- Coccidioidomycosis –> Southwestern US, California
- Paracoccidioidomycosis –> Latin America
4
Q
systemic mycosis - size vs RBC
A
- Histoplasmosis - smaller
- Blastomycosis - same
- Coccidioidomycosis - much larger
- Paracoccidioidomycosis - much larger
5
Q
Histoplasmosis - source / causes
A
Bird or bat dropping
- pneumonia and erythema nodosum
6
Q
patient with suspected sarcoidosis deteriorates after steoroids
A
HIstoplasma
7
Q
histoplasmosis - unique signs / symptoms / diagnosis
A
palatal/tongue ulcers / splenomegaly
- urine / serum antigen
8
Q
Blastomycpsis - clinical features
A
lung: acute + chronic pnneumonia
2. skin: wartlike lesions, violacceous nodules, skin ulcers
3. Bone: osteomyelitis
4. GI: prostatis, epidiymo-orchitis
5. CNS: meningitis, epidural or brain abscess
GRANOULOMAS
9
Q
Coccidioidomycosis causes / treatment
A
enedemic mycosis of southwest desert –> CAP often accompanied by arthralgias, erythema nodosum, erythema multiforme –> symptoms may last weeks to months –> no treatment for healty patients –> ketoconazole or fluconazole for patients with risk for dissemination (immunocompromised)
(VALLEY FEVER)
10
Q
Coccidioidomycosis - case rate increases after … (WHY)
A
earthquakes (spores in dust thrown into air –> inhaled –> spheruls in lung
11
Q
Coccidioidomycosis is also called
A
Valley fever
12
Q
Paracocciddioidomycosis under the microscope
A
Budding yeast with “captain’s wheel formation
much larger than RBCs
13
Q
systemic mycosis - erythema nodosum
A
- Coccidioidomycosis
2. Histoplasmosis
14
Q
systemic mycosis - under the microscope
A
- Histoplasmosis –> Macrophages filled with Histoplasma
- Blastomycosis –> Broad-base budding
- Coccidioidomycosis –> spherule filled with endospores
- Paracoccidioidomycosis –> captain wheel
- -> shines
15
Q
Cutaneous mycoses are divided to
A
- tinea (dermatophytoses)
2. tinea versicolor
16
Q
Dermatohytes - appearance / include …
A
branching septate hyphae visible on KOH preparation with blue fungal stain
- Microsporum
- Trichophyton
- Epidermophyton
17
Q
Cutaneous mycoses - types
A
- tinea capitis (dermatophytoses)
- tinea corporis (dermatophytoses)
- tinea cruris (dermatophytoses)
- tinea pedis (dermatophytoses)
- tinea unguium (dermatophytoses)
- Tinea versicolor
18
Q
Tinea capitis occurs on (area of the body) / symptoms
A
- head scalp
- lympadenopathy
- alopecia
- scaling
- lympadenopathy
19
Q
Tinea corporis - area of the body / symtpoms
A
torso (κορμός)
erythematous scaling rings (ringworm) and central clearing
20
Q
Tinea corporis can be acquired from
A
contact with an infected cat or dog
21
Q
Tinea cruris - occur in (area of the body) / symptoms
A
inguinal area
rash in the inguinal area without the central clearing seen in the tinea corporis
22
Q
Tinea unguium - is also called / area of the body
A
onychomycosis
nails
23
Q
Tinea pedis - how many varieties and which (MC) / AKA
A
- interdigital (MC)
- Moccasin distribution
- Vesicular type (blister)
AKA: athlete’s foot
24
Q
Tinea versicolor is caused by
A
Malassezia spp (Pitirosporum spp)
25
Tinea versicolor - whether
any time of year but common in summer (hot, humid weather)
26
Tinea versicolor - under microscopy / treatment
spaghetti and meatballs
- 1. topical and/oral antifungul medication
2. selenium sulfate
27
opportunistic fungal infections - bugs?
1. Candida ablicans
2. Aspergillus Fugimatus
3. Cryptococcus neoformans
4. Mucor and Rhizopus spp.
5. Pneumocystis jirovecii
6. Sporothrix schenckii
28
Candida ablicans causes .... (and situations)
1. Oral and esophageal thrush (immunocompromised --> neonates, steroids, diabetes, AIDS)
2. vulvovaginitis (diabetes, antibiotics)
3. diaper rash
4. endocarditis (iv drug users)
5. disseminated candidiasis
6. chronic mucocutaneous candidiasis
7. osteomyelitis (IV drugs)
29
Candida ablicans - morphology
DIMORPHIC
pseudohyphae and budding yeast at twenty c.
germ tubes at thirty seven c
30
Candida ablicans - treatment
topical azole for vagina
nystatin, fluconazole or caspofungin for oral/esophageal
fluconazole or amphotericin B for systemic
31
Aspergillus fugimatous causes ... (and situations)
1. invasive aspergillosis (immunocompromised and with chronic granulomatous disease)
2. Allergic bronchopulmonary aspergillosis (associated with asthma, cystic fibrosis) --> bronhiectasia and eosinophilia
3. Aspergillomas in lung cavitieus (esp after TB)
4. produce aflatoxins --> hepatocellular CA
32
Aspergillus fugimatous - morphology
```
NOT dimorphic (only as a mold)
Septate yphae that branches at 45 angle
conidophore with radiating chains of spores
```
33
Cryptococcus neoformans causes / morphology
1. meningitis
2. cryptococcosis
3. cryptococcal encephalitis
- heavily encapsuled yeast. NOT DIMORPHIC
5-10μm (NARROW BASED BUD)
34
Cryptococcus neoformans is found in
soil
| pigeon dropping
35
Cryptococcus neoformans - lab
Culture on Sabouraud agar
Stain with india ink and mucocarmine
latex agglutination test detects polysaccharide capsular antigen
soap bubble lesion in brain image (in cryptococcal encephalitis)
36
Cryptococcus neoformans - lab - most specific test
latex agglutination test detects polysaccharide capsular antigen
37
Rhino-orbital-cerebral mucormycosis - manifestation
Acute/aggresive
fever, nasal congestion, purulent nasal discharge, headache, sinus pain
NECROTIC invasion of palate, orbit, brain
38
Mucormycosis - pathophysiology / diagnosis
fungi proliferation on blood vessel walls, pemetrate cribiform plate and enter brain
- sinus endoscopy with biopsy + culture
39
Rhino-orbital-cerebral mucormycosis - RF
1. DM (ketoacidosis)
2. hematologic malign
3. Solid organ or stem cell transplant
40
Mucormycosis treatment
1. surgical debridement
2. liposomal amphotericin
3. elimination of risk factors
41
Mucor morphology
NOT DIMORPHIC
| irregular, broad nonseptae hyphae at wide angles
42
Pneumocystis jirevecii - morphology / originally classified as
yeast like fungus (disc shape)
| originally classified as protozoan
43
Pneumocystis jirevecii - start prophylaxis when
CD4 cound drops under 200 cells/mm3 in HIV patients
44
sporothrichosis - manifestation
subacute / chronic
- skin papule --> ulceratio nwith nonpurulent odorless drainage
- proximal lesions along lymphatic chaein
- lymphadenopahrym deepr spread and sysemic symptoms are RARE
45
Sporothrix schenckii - morphology
Dimorphic, cigar shaped budding yeast that grows in branching hyphae with rosettes of conidia
46
Sporothrix schenckii - treatment
3-6 months of oral intraconazole
47
opportunistic fungal infections - dimorphic fungi
1. Candida ablicans
| 2. Sporothrix schenckii
48
Oppostunistic fungal infection - morphology of every fungus
1. Candida ablicans - dimorphic: pseudohyphae and budding yeast at 20c. germ tubes at 37c
2. Aspergillus Fugimatus - not dimorphic (only as a mold). Septate hyphae that branches at 45 angle
conidophore with radiating chains of spores
3. Cryptococcus neoformans: heavily encapsuled yeast. not dimorphic, 5-10μm (NARROW BASED BUD)
4. Mucor and Rhizopus spp: not dimorphic, irregular, broad nonseptae hyphae at wide angles
5. Pneumocystis jirovecii: Disc-shaped yeast-like
6. Sporothrix schenckii: Dimorphic, cigar shaped budding yeast that grows in branching hyphae with rosettes of conidia
49
Histoplasma in HIV - RFs and prophylaxis
RF: CD less than 150, endemic area: Ohio and Misisipi river valley (bird or bat dropping)
prophylaxis: intraconazole
50
progressive disseminated histoplasmosis - how to diagnose
urine or serum histoplasma antigen
also pancytopenia
- cultures takes 4-6 wks
51
progressive dissaminated histoplasmosis - treatment
amphotericin B for 1 week --> after clinical improvement --> oral intraconazole for 1 year
52
candida esoph - treatment
3-5 days fluconazole
53
special characteristics on manifestation of cryptococcal meningitis
no neck stiffness
no photophobia
increased intracranial pressure
54
Cryptococcal meingitis - treatment
IV amphotericin (+ fluticosine)
stop antiretroviral therapy for at least 2 weaks
maybe LPs to decreased pressure
55
PCP pneumonia treatment
TMP-SXM
| prednisone if low O2 levels less than 92% or PO2 less than 70 or arterial - alveolar gradient more than 35
56
PCP - skin
nodular and papular cutaneous lesions of the external auditory meatus in immunocompromised patiends
57
indications for adding corticosteroids to TMP-SXM in PCP treatment
- Pa02 70 or lower
| - A-a gradient 35 or more on room air
58
PCP alternatives
1. Pentamidine (IV)
2. atovquone
3. Timethoprim + dapsone
4. Clindamycin (IV or oral) + primaquine (oral)
59
PCP - workupe
- LDL elevated
- diffuse reticular infiltrates on imaging
- BAL
60
sporotrichosis - epidemiology
- sporothrix schenckii (dimorphic fungus)
- decaying plant matter / soil
- darnders + landscapers
61
Membrane pores formers - drugs - and mechasnim of action
1. Amphotericin B 2. Nystatin
Binds to ergosterol (unique to fungi) --> membranes pores that allow leakage of electrolytes
(harmless for host cells)
62
Amphotericin B - clinical use
1. SERIOUS SYSTEMIC MYCOTIC INFECTIONS : Histoplasmosis, Blastomycosis, Coccidioidomycosis, Mucor, Candida, Cryptococcus
2. Naegleria Fowleri
3. Leismania Donovani
63
Amphotericin B - meningitis
- with/without flucytosine for cryptococcal meningitis
| - Intrathecally for fungal meningitis
64
Amphotericin B - administrate with (and why)
supplement K+ and Mg2+ because of altered renal tubule permeability
65
Amphotericin B - toxicity
1. fever/chills (shake and bake)
2. Hypotenesion
3. nephrotoxicity
4. arrhythmias
5. anemia
6. IV phlebitis
66
Amphotericin B - solution of toxicity
1. Hydration decreases nephrotoxicity
| 2. Liposomal amphotericin --> decreased toxicity
67
Nystatin - clinical use
TOPICAL USE ONLY (TOO TOXIC FOR SYSTEMIC USE)
1. oral candidiasis (swish and swallow)
2. topical for diaper rash or vaginal candidiasis
68
Flucytosine - mechanism of action
Inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase --> inhibits thymidylate synthetase
69
Flucytosine - clinical use
| toxicity
Systemic fungal infections (esp meningitis caused by Cryptococcus) in combination with amphotericin B
- Bone marrow suppression
70
azoles - mechanism of action
inhibit fungal stero (ergosterol) synthesis by inhibiting the cytochrome P-450 enzyme that converts lanosterol to ergosterol (14-α-demethylase)
71
azoles - clinical use
Local and less serious systemic mycoses:
- Fluconazole: chronic suppression of cryptococcal meningitis in AIDS patients, all types of candidal infections, LOCAL systemic mycoses
- Intraconazole: (LOCAL systemic mycoses) Blastomyces, Coccidioides, Histoplasma
- Clotrimazole, miconazole: topical fungal infection
72
Azoles - toxicity
1. testosterone synthesis inhibition --> gynecomastia (esp ketoconazole)
2. liver dysfunction (inhibits P450)
73
Terbinafine - mechanism of action / clinical use
inhibits the fungal enzyme squalene epoxidase (Lanosterol synthesis inhibitor)
- Dermathophytes (esp onychomycoses)
74
Terbinafine - toxicity
1. GI upset
2. headaches
3. hepatotoxicity
4. Taste disturbance
75
Echinocandins - drugs and mechanism of action
Echinocandins --> 1. Anidulafungin 2. caspofungin
3. micafungin
inhibit cell wall synthesis by inhibiting synthesis of β-glucan
76
Echinocandins - clinical use
1. invasive aspergilosis
| 2. Candida
77
Echinocandins - drugs and toxicity
Echinocandins --> 1. Anidulafungin 2. caspofungin
3. micafungin
GI upset, flushing (by histamine release)
78
Griseofulvin - clinical use
1. oral treatment of superficial infections
| 2. inhibits growth of dermatophytes (tinea, ringworm)
79
Griseofulvin - toxicity
1. teratogenic 2. carcinogenic 3. confusion 4. headaches 5. increased cytochrome P-450 and warfarin metabolism
