4/30 Fungal Infections and Immunizations Ch 18, 19, 20 Flashcards Preview

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Flashcards in 4/30 Fungal Infections and Immunizations Ch 18, 19, 20 Deck (57)
1

GIve an example of herd immunity

Rates of disease in adults going down after most children were given vaccines.

2

Live vaccines can be transmitted from person to person - this is not usually a problem except in what circumstances? 

Among immunologically vulnerable hosts

3

define passive immunization

How long does the protective effect last?

Giving a patient immunoglobulins from an already immune individual

Protectin lasts only a few weeks

4

define active immunization

stimulation longer-lasting immune responses via injection of something that stimulates an immune response in the host

5

examples of live attenuated vaccines?

is a single dose sufficient for immunity? explain

Examples: Polio, rotavirus, typhoid, BCG (for TB)

single dose may be sufficient; this type of vaccine can elicit broad immunity

6

example of inactivated vaccines; inactivated whole organisms?

-tetanus, diptheria, Hep B recombinant protein antigen, pneumococcal polysaccharide vaccine (PPV23)

7

example of vaccine given as viral-like particles?

HPV

8

Example of vaccines given as inactivated: bacterial capsular polysaccharide conjugated to an immunogenic protein?

comment on this type of vaccine?

-pneumococcal conjugate vaccine. H flu, meningococcal conjugate

-induce only B cell responses without conjugate; often require booster doses to be protective

9

what do we measure to determine if a vaccine has been "immunogenic"?

measure antibody responses.

10

define vaccine efficacy (what does it measure)?

how is it expressed?

Vaccine efficacy = measures the ability of the vaccine to prevent disease or disease-related events (death, hospitalization)

expressed as a percentage: # protected/#at risk

Determine efficacy via prospective randomized trial

11

adverse reactions to vaccines: generally mild or severe?

examples of reactions?

generally mild

can range from local injection site reactions to low grade temps

in immunocompromized pts, more severe systemic infection is possible

reports of febrile seizures, Guillian-Barre syndrome: hard to prove causality!

12

define universal vaccination

one approach to immunization; aim is to prevent all individuals from getting disease, commonly administered in childhood (unless there are reasons to give later in life)

13

example when would we vaccinate only risk groups rather than universally?

ex: giving Hep A immunization to travelers or others at particular risk

14

define underlying risk

can signify risk such as pneumococcal vaccination for immunocompromised and elderly hosts.

his notes don't make much sense here.

15

for what diseases can we provide post-exposure prophylaxis?

rabies, measles, Hep B, HIV

16

for what disease do we only vaccinate after a disease outbreak?

menincococcus

17

2 contraindications to immunization with live vaccines?

-pregnancy

-immunodeficiency

18

most vaccination is voluntary or not? 

are there any mandated immunizations?

most vaccination is voluntary

some are mandated by school requirements, military requirements, for healthcare workers

reason: unvaccinated people can be a risk to those around them.

19

Dimorphic fungi: what makes them dimorphic? why do we care?

organisms that live in the environment in one form, and in infected tissue in another.

In environment: filaments with hyphae and septae. In tissue: yeast form (round/oval structures that divide by budding)

The diseases they cause (that we need to know about) are called Deep Mycoses - meaning that they are not limited to skin or mucosa.

20

Histoplasmosis: geographic distribution?

what types of places will you find histo?

In US: misissippi/ohio river valleys

Global: Central/South america

Find it in caves, soils that have bird/bad droppings, chicken coops, renovating old houses

Remember the CF patient who went cave exploring? This must be why everyone was so horrified.

21

Patient visited a cave in Belize. has a fungal infection in his lungs. what is it? what med?

Histoplasmosis (based on cave, S america)

Itraconazole

22

Histoplasmosis: Pathogenesis?

Tiny little yeasts grow within macrophages.

causes reaction resembling TB - fibrosis, caseating necrosis

cytokines activated macrophages to kill yeasts.

23

Histoplasmosis: clinical sx?

initial: flu-like (cough, fever, malaise).

upon reinfection, may get acute pulm infiltrates; febrile illness

Chronic: fibrosis and cavitary infiltrates

24

all these fungi have what general presentation in immunocompromised?

cell-mediated reaction -> granulomas. the granulomas may disseminate and allow live fungi into other tissues 

--> meningitis, bone granulomas, other organ lesions.

Kind of like TB that then spreads widely

25

How can we diagnose Histo?

Culture grown from resp specimen (or other sites, if dz is disseminated)

26

Histo: treatment?

-severe, progressive dz with CNS involvement?

-suppress chronic infection in immunocomp host?

Ampho B for severe/CNS disease

Itraconazole for immunocomp host

27

Blastomycosis: US distribution?

global distribution?

what types of places is it found?

US: Pretty widely spread from midwest -> east coast. His example was a guy from VT.

-Scattered worldwide

-Soil, rivers, ponds: ppl with outdoor occupations are at risk (ex: woodworker)

28

Blastomycosis: appearance of the yeast?

Broad based buds.

extracellular (not within Macrophages, as with Histo)

thick-walled yeast.

29

Blastomycosis: clinical sx?

Pulm infection

-Cutaneous - may resemble carcinoma!

-can disseminate to GU, CNS.

30

Blastomycosis: treatment?

Serious disease: Amphotericin B

Non-meningeal or moderate: Itraconazole

31

Blastomycosis: diagnosis?

Stains show yeast forms

Culture will reveal mycelial form

32

Sporotichosis: geographic presentation?

what types of places is it found?

Geog: worldwide

associated with rotting wood, moss, potting soil, rose bushes

33

Sporotrichosis: pathogenesis?

local inoculation (usually an arm/hand; think prick from rose bush)

-pyogramulamatous reponse

-lymphatic spread

34

Sporotrichosis: clinical sx?

local pustules/ulcers with PAINLESS red nodules forming along draining lymphatics (ascending lymphangitis.

may have osteoarticular involvement and tenosynovitis.

litlte systemic illness - lung involvement is rare.

35

Sporotrichosis: diagnosis?

culture: yeast colonies

cigar shaped yeast on histo but hard to find.

36

Sporotrichosis: treatment?

Potassium iodide: may assist macrophages in killing Sporo

Local heat

Itraconazole (?fewer side effects that Pot iodide)?

37

Coccidiomycosis: geography?

types of locations?

US: Western states, Arizona, Central valley of CA (--> valley fever)

-Central/S America

Found in soils, rodent burrows

38

Coccidio: pathogenesis?

inhaled spores, pulm infection

granulomatous response; may look like erythema nodosum. 

39

Coccidio: sx?

Primarily pulm: remember valley fever + lungs

erythema nodosum

may disseminate to bone, skin, meninges

40

Coccidio and immunocompromised pts: sx?

HIV+ at incr risk 

may disseminate in these patients.

41

Coccidio: dx?

serology for antibodies

culture (but watch out; aerosolizes rapidly!)

42

Coccodio: tx?

Mild/primary dz usually not treated (but FA says itracolazole)

Ampho B for progressive dz/HIV patients

 

43

Candida: what are the normal host defenses?

-Phagocytic. Monocytes, macrophages, eosinophils can all ingest candida

-Cellular immunity. as evidenced by HIV patients (impaired cellular immunity) being at incr risk for Candida

44

Candida: clinical manifestations?

Mucus membranes!

-Vaginosis: thick creamy discharge. itching. erythema

Esophagitis: Pain w swallowing, feeling of obstruction.

Thrush: can be scraped off. white patches on tonge etc. 

45

Candidemia: what is this?

what are sx? 

risk factors?

dx?

Invasive candida that has reached the bloodstream

sx: spectrum: mild fever to sepsis.

Risk: immunocompromised, central IV catheters

Dx: blood culture

46

Candidemia: what drugs to give?

Ampho B, Caspofungin, or Fluconazole (PO)

may need to remove foreign bodies (catheter, IV)

47

Aspergillus: what are the host defenses?

sim to candida

-Phagocytic cells

-Cell mediated immunity

 

48

Classic presentation of Aspergillus?

-cavitary lung lesion "fungus ball"

-May colonize sinuses

-May dessimate, esp in immunocompromised

49

Aspergillosis: Treatment?

-for sinus disease, focal necroticlesions?

-meds?

-for sinus disease, brain disease, fungal balls in lung: surgical debridement

-Meds: Voriconazole (Jullet's pic with a V on it: 45' hyphal angle)

Ampho B effective but toxic

Caspofungin for refractory

Posaconazole may work

50

Zygomycosis (aka mucormycosis): why is disease from this limited to immunocompromised people?

It is ubiquitous in the env't; not very virulent

51

Mucormycosis: pathogenesis?

Enters body via resp tract. hyphae invade tissue with affinity to blood vessels.

Thrombosis/necrosis. 

52

Mucormycosis: risk factors?

Diabetes, esp with acidosis

53

Mucormycosis: clinical sx?

Dx?

rhinocerebral mucormycosis. sinusitis, pain, ha, fever.

May eride through face and hard palate!!! -> cerebral abscess. 

May need CT scan

54

Mucormycosis: Prognosis?

treatment?

very poor prognosis (25-80% mortality)

-Tx: surgery? Ampho B, Posaconazole (PO)

55

Cryptococcosis: Presentation?

CNS meningioencephalitis

cranial nerve involvement. headache, facial weakness, diplopia

56

Cryptococcus: diagnosis?

Cryptococcal Antigen testing. Mainstay of diagnosis. 

57

Cryptococcus: Treatment?

-improve immune status

-serial lumbar puncture if needed (can cause incr CSF pressure)

-Fluconazole

-Ampho B and flucytosine (5-FU).