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

1
Q

GIve an example of herd immunity

A

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

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2
Q

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

A

Among immunologically vulnerable hosts

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3
Q

define passive immunization

How long does the protective effect last?

A

Giving a patient immunoglobulins from an already immune individual

Protectin lasts only a few weeks

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4
Q

define active immunization

A

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

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5
Q

examples of live attenuated vaccines?

is a single dose sufficient for immunity? explain

A

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

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

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6
Q

example of inactivated vaccines; inactivated whole organisms?

A

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

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7
Q

example of vaccine given as viral-like particles?

A

HPV

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8
Q

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

comment on this type of vaccine?

A
  • pneumococcal conjugate vaccine. H flu, meningococcal conjugate
  • induce only B cell responses without conjugate; often require booster doses to be protective
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9
Q

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

A

measure antibody responses.

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10
Q

define vaccine efficacy (what does it measure)?

how is it expressed?

A

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

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11
Q

adverse reactions to vaccines: generally mild or severe?

examples of reactions?

A

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!

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12
Q

define universal vaccination

A

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)

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13
Q

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

A

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

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14
Q

define underlying risk

A

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

his notes don’t make much sense here.

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15
Q

for what diseases can we provide post-exposure prophylaxis?

A

rabies, measles, Hep B, HIV

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16
Q

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

A

menincococcus

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17
Q

2 contraindications to immunization with live vaccines?

A
  • pregnancy
  • immunodeficiency
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18
Q

most vaccination is voluntary or not?

are there any mandated immunizations?

A

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.

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19
Q

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

A

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.

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20
Q

Histoplasmosis: geographic distribution?

what types of places will you find histo?

A

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.

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21
Q

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

A

Histoplasmosis (based on cave, S america)

Itraconazole

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22
Q

Histoplasmosis: Pathogenesis?

A

Tiny little yeasts grow within macrophages.

causes reaction resembling TB - fibrosis, caseating necrosis

cytokines activated macrophages to kill yeasts.

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23
Q

Histoplasmosis: clinical sx?

A

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

upon reinfection, may get acute pulm infiltrates; febrile illness

Chronic: fibrosis and cavitary infiltrates

24
Q

all these fungi have what general presentation in immunocompromised?

A

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
Q

How can we diagnose Histo?

A

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

26
Q

Histo: treatment?

  • severe, progressive dz with CNS involvement?
  • suppress chronic infection in immunocomp host?
A

Ampho B for severe/CNS disease

Itraconazole for immunocomp host

27
Q

Blastomycosis: US distribution?

global distribution?

what types of places is it found?

A

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
Q

Blastomycosis: appearance of the yeast?

A

Broad based buds.

extracellular (not within Macrophages, as with Histo)

thick-walled yeast.

29
Q

Blastomycosis: clinical sx?

A

Pulm infection

  • Cutaneous - may resemble carcinoma!
  • can disseminate to GU, CNS.
30
Q

Blastomycosis: treatment?

A

Serious disease: Amphotericin B

Non-meningeal or moderate: Itraconazole

31
Q

Blastomycosis: diagnosis?

A

Stains show yeast forms

Culture will reveal mycelial form

32
Q

Sporotichosis: geographic presentation?

what types of places is it found?

A

Geog: worldwide

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

33
Q

Sporotrichosis: pathogenesis?

A

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

  • pyogramulamatous reponse
  • lymphatic spread
34
Q

Sporotrichosis: clinical sx?

A

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
Q

Sporotrichosis: diagnosis?

A

culture: yeast colonies

cigar shaped yeast on histo but hard to find.

36
Q

Sporotrichosis: treatment?

A

Potassium iodide: may assist macrophages in killing Sporo

Local heat

Itraconazole (?fewer side effects that Pot iodide)?

37
Q

Coccidiomycosis: geography?

types of locations?

A

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

-Central/S America

Found in soils, rodent burrows

38
Q

Coccidio: pathogenesis?

A

inhaled spores, pulm infection

granulomatous response; may look like erythema nodosum.

39
Q

Coccidio: sx?

A

Primarily pulm: remember valley fever + lungs

erythema nodosum

may disseminate to bone, skin, meninges

40
Q

Coccidio and immunocompromised pts: sx?

A

HIV+ at incr risk

may disseminate in these patients.

41
Q

Coccidio: dx?

A

serology for antibodies

culture (but watch out; aerosolizes rapidly!)

42
Q

Coccodio: tx?

A

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

Ampho B for progressive dz/HIV patients

43
Q

Candida: what are the normal host defenses?

A
  • 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
Q

Candida: clinical manifestations?

A

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
Q

Candidemia: what is this?

what are sx?

risk factors?

dx?

A

Invasive candida that has reached the bloodstream

sx: spectrum: mild fever to sepsis.

Risk: immunocompromised, central IV catheters

Dx: blood culture

46
Q

Candidemia: what drugs to give?

A

Ampho B, Caspofungin, or Fluconazole (PO)

may need to remove foreign bodies (catheter, IV)

47
Q

Aspergillus: what are the host defenses?

A

sim to candida

  • Phagocytic cells
  • Cell mediated immunity
48
Q

Classic presentation of Aspergillus?

A
  • cavitary lung lesion “fungus ball”
  • May colonize sinuses
  • May dessimate, esp in immunocompromised
49
Q

Aspergillosis: Treatment?

  • for sinus disease, focal necroticlesions?
  • meds?
A
  • 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
Q

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

A

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

51
Q

Mucormycosis: pathogenesis?

A

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

Thrombosis/necrosis.

52
Q

Mucormycosis: risk factors?

A

Diabetes, esp with acidosis

53
Q

Mucormycosis: clinical sx?

Dx?

A

rhinocerebral mucormycosis. sinusitis, pain, ha, fever.

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

May need CT scan

54
Q

Mucormycosis: Prognosis?

treatment?

A

very poor prognosis (25-80% mortality)

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

55
Q

Cryptococcosis: Presentation?

A

CNS meningioencephalitis

cranial nerve involvement. headache, facial weakness, diplopia

56
Q

Cryptococcus: diagnosis?

A

Cryptococcal Antigen testing. Mainstay of diagnosis.

57
Q

Cryptococcus: Treatment?

A
  • improve immune status
  • serial lumbar puncture if needed (can cause incr CSF pressure)
  • Fluconazole
  • Ampho B and flucytosine (5-FU).