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Flashcards in Sketchy Micro Deck (129)
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1
Q

Associate bird or bat droppings with what fungus?

A

Histoplasma

also spelunking

2
Q

Where is histoplasma endemic to?

A

Midwestern US

3
Q

How is histoplasma transmitted?

A

Spores, airborne

4
Q

How big is histoplasma as compared with RBCs?

A

Smaller

Many histo spores (ovoid bodies) can be found within macrophages

5
Q

What kind of fungus is histoplasma?

A

Dimorphic

Mold in the cold, yeast in the heat

6
Q

What is the treatment for histoplasma?

A

Itraconazole

7
Q

The calcified granulomas of histoplasma resemble what infection

A

TB

8
Q

Where is blastomycosis endemic to?

A

Great lakes, Ohio River Valley, Southern US

9
Q

Is blastomycosis dimorphic?

A

Yes

Mold in the cold, yeast in the heat

10
Q

How is blastomycosis transmitted?

A

Inhalation of spores

11
Q

How big is blastomycosis w/r/t RBCs?

A

Almost the same size as RBCs

12
Q

How would a CXR look of a person with a blastomycosis infection?

A

Hazy, with patchy alveolar infiltrate

13
Q

Disseminated infection with blastomycosis, as with an immunocompromised patient, presents with

A

Skin and bone issues such as osteomyelitis

14
Q

T/F: Infection with blastomycosis can be either acute or chronic.

A

True

15
Q

How is blastomycosis diagnosed?

A

KOH wet mount;
Culture;
Urine antigen test

16
Q

How is blastomycosis treated?

A

azoles for local infection, ie itraconazole

amphotericin B for disseminated infection

17
Q

How does blastomycosis appear under the microscope?

A

Broad based budding (looks like balls)

18
Q

Where is coccidiodes endemic to?

A

Southwestern US

19
Q

How is coccidiodes transmitted?

A

Inhalation

Earthquakes are a risk factor bc of dust.

20
Q

What kind of organism is coccidiodes?

A

Dimorph
Mold in the cold
Spherules of endospores in the heat

21
Q

How big is coccidiodes w/r/t RBCs?

A

Bigger than RBCs

22
Q

What is the presentation of coccidiodes infection in a healthy person?

A

Asymptomatic subclinical - pneumonia-like with coughing and arthralgia

23
Q

What does the CXR of a patient with coccidiodes infection look like?

A

CXR can show cavities or nodules

24
Q

Seeing erythema nodosum on a patient with coccidiodes indicates what clinical scenario?

A

It indicates that the patient is having a robust immune response

25
Q

Infection of coccidiodes in an immunocomprimised patient would show what?

A

Skin and bone involvement, as well as meningitis

26
Q

How is coccidiodes diagnosed?

A

KOH
Culture
Serology for IgM

27
Q

What is the treatment for coccidiodes?

A

Local lung infection, can use azole drugs;

Systemic infection, use amphotericin B

28
Q

What is the regional distribution of paracoccidiodes?

A

South America

29
Q

How does paracoccidiodes appear?

A

Captain’s wheel - multiple buds from one single center

30
Q

What fungal form does paracoccidiodes assume in the lung?

A

Yeast in the lung;

Mold in the environment

31
Q

What size is paracoccidiodes w/r/t RBCs?

A

Paracoccidiodes is larger than RBCs

32
Q

What is the mode of transmission for paracoccidiodes?

A

Respiratory droplets

33
Q

What are the symptoms of infection with paracoccidiodes?

A

Coughing
Cervical lymphadenopathy
Granulomas in lungs
Mucocutaneous lesions

34
Q

How is infection with paracoccidiodes treated?

A

Itraconazole for mild infection;

Amphotericin B for severe infection

35
Q

What is a unique feature of cryptococcus neoformans?

A

cryptococcus neoformans is heavily encapsulated

**Has a repeating polysaccharide capsular antigen which lends itself to being tested with the latex agglutination test

36
Q

Where is cryptococcus neoformans found?

A

Soil
Pidgeon droppings
Can stay infectious for a LONG time

37
Q

What is the mode of transmission of cryptococcus neoformans?

A

Inhalation

Primary focus of infection is the lungs

38
Q

Is cryptococcus neoformans urease (+) or (-)?

A

Urease (+)

39
Q

What population is most at risk for infection from cryptococcus neoformans?

A

The immunocomprimised, particularly HIV patients

40
Q

How does infection with cryptococcus neoformans present?

A

Cryptococcal pneumonia, fever, cough, dyspnea

41
Q

What is a severe presentation of cryptococcus neoformans infection?

A

Meningitis, often results in neurological deficits

42
Q

How is cryptococcus neoformans grown in culture?

A

Sabauraud’s agar
silver stain = methanamine
red stain = mucicarmine

43
Q

Under the microscope, what feature does cryptococcus neoformans have?

A

Wide capsular halo

44
Q

On gross pathology, what distinctive features does cryptococcus neoformans have?

A

Soap bubble lesions on gray matter of brain

45
Q

What is the treatment for infection with cryptococcus neoformans?

A

Amphotericin B and flucytozine (and fluconazole) - joint

46
Q

What populations are particularly susceptible to infection with mucormycosis?

A

Leukemics
Diabetics
Neutropenics
(immunocompromised)

47
Q

How is mucormycosis (or rhizopus) transmitted?

A

Spore inhalation

**DKA (excess ketones, as with unmanaged diabetes, is a major risk factor)

48
Q

How does mucormycosis appear?

A

Wide angle branching rods, nonseptate

49
Q

Where does mucormycosis like to profilerate?

A

Blood vessels

50
Q

Where does mucormycosis like to go when it infects?

A

It like to cross the cribiform plate and go to the brain, it creates gigantic lesions ie rhinocerebral mucormycosis, results in eschars (abscesses) on the face

51
Q

How is infection with mucormycosis treated?

A

Surgical debridement of necrotic tissue
Amphotericin B
this baby is a killer**

52
Q

What bacterial infection is often fatal in burn patients?

A

Pseudomonas

53
Q
Pseudomonas is:
Gram \_\_\_
Shape:
Oxidase \_\_\_
Catalase \_\_\_
Capsule or no capsule?
A
Gram (-) encapsulated bacillus
Oxidase +
Catalase + (associated with chronic granulomatous disease)
Obligate aerobe
enterobacteriaciae
54
Q

What is the #1 cause of nosocomial pneumonia?

A

Pseudomonas;

common cause of respiratory failure in CF patients

55
Q

Pseudomonas can progress to what infection in diabetics and IV drug users?

A

Osteomyelitis

56
Q

Erythema gangrenosum are black skin lesions caused by sepsis induced by what organism?

A

Pseudomonas

57
Q

Exotoxin A is a virulence factor of what bacterium?

A

Pseudomonas

58
Q

How is pseudomonas treated?

A

Pipercillin/tazobactam;
Aminoglycosides in combination in beta lactams;
Fluroquinolones for UTI (indwelling catheter patients)

59
Q

Psuedomonas can cause what pruritic papulopustular infection?

A

Hot tub folliculitis - underchlorination of hot tubs

60
Q

Legionella causes what 2 presentations?

A
  1. Legionnaire’s disease - atypical pneumonia seen in smokers;
  2. Pontiac fever - self-limiting
61
Q

What stain should legionella be visualized with?

A

Silver stain
Legionella is a gram (-) bacillus but can’t use H&E
Oxidase (+)

62
Q

How is legionella transmitted?

A

From the source, not contagious person to person

63
Q

How is legionella grown?

A

Special agar - buffered charcoal yeast extract w/ cysteine and iron

64
Q

What is seen on CXR of a patient with Legionnaire’s diseasE?

A

Patchy infiltrate with consolidation of 1 lobe

65
Q
A patient has the following symptoms:
Hyponatremia;
Neurologic symptoms - HA, confusion;
Diarrhea;
High fever;
Pneumonia-like symptoms
What is the likely pathogen?
A

Legionella

66
Q

How is legionella diagnosed?

A

Culture respiratory sputum
Special agar - buffered charcoal yeast extract w/ cysteine and iron
Visualize with silver stain OR

Rapid urine antigen test

67
Q

What is the treatment for legionella?

A

Macrolides

Fluoroquinolones

68
Q

What is the taxonomy of Coxielle Burnetti?

A

Gram (-)

Obligate intracellular

69
Q

Q Fever is caused by what pathogen?

A

Coxielle Burnetti

70
Q

How is Coxiella Burnetti transmitted?

A

Kicked up in dirt and farm animal droppings - aerosol transmission;
Or vets that deal in the birth of farm animals (placental secretions)

71
Q

What are the symptoms of Q fever?

A
Caused by Coxielle Burnetti:
Pneumonia
HA
fever
HEPATITIS***
usually self-limiting
72
Q

What is a rare complication of Q fever (Coxiella Burnetti) that can be seen in immunocompromised patients?

A

Endocarditis

73
Q

The wheal seen in a + PPD is what type of hypersensitivity reaction?

A

Type IV

74
Q

What virulence factors prevent TB from being destroyed?

A

Cord factor - serpentine shape - prevents mycobacterium from destruction;
Sulfatides allow TB to survive in macrophages and prevent formation of the phagolysosome

75
Q

What is the taxonomy of Mycobacteerium tuberculosis?

A

Acid-fast

Obligate aerobe

76
Q

What is a tuberculoma?

A

Cavitary lesion in the brain caused by TB infection

77
Q

What is the acronym for TB treatment?

A

RIPE

Rifampin - Isoniazid - Pyrazinamide - Ethambutol

78
Q

The tuberculoid form of M. leprae infection is what kind of immune response?

A

Th1 - cell-mediated immunity - body can contain infection within macrophages
presents with well-demarcated, hairless plaque on skin

79
Q

The lepromatous form of M. leprae infection is what kind of immune response?

A

Th2 - humoral response - body cannot contain infection within macrophages - reason for neuropathy and lesions on extensor surfaces, leonine facies

80
Q

Is there human to human transmission of M. leprae?

A

Yes, esp where lepromatous form predominates

81
Q

What is the reservoir for M. Leprae in the U.S.?

A

Armadillo

82
Q

Name the virus:
Naked
DNA virus
#1 cause of tonsillitis

A

Adenovirus

common cause of conjunctivitis also

83
Q

What populations are at risk for getting adenovirus?

A

Military recruits (can receive a live vaccine);
People who swim in public pools;
Children

84
Q

What virus is responsible for the complication of hemorrhagic cystitis?

A

Adenovirus

85
Q

Aspergillus fumigatus is a conidia that shares what feature with bacteria?

A

It’s catalase +

86
Q

Aflatoxins that cause hepatocellular carcinomas are what kind of aspergillus?

A

Aspergillus FLAVUS

87
Q

How does aspergillus appear under the microscope?

A

Acute angles (

88
Q

How is aspergillus transmitted?

A

Inhalation

89
Q

Aspergillus causes what kinds of infections?

A

THREE:

  1. Allergic bronchopulmonary aspergillosis (ABPA) -
  2. Aspergillomas - balls of fungus in the lungs
  3. Angioinvasive Aspergillosis - WORST
90
Q

Allergic bronchopulmonary aspergillosis (ABPA) is what kind of hypersensitivity reaction?

A

Type 1
Wheezing, fever, **migratory pulmonary infiltrate, increased IgE
can be seen in CF patients

91
Q

What patient populations are at risk for developing aspergillomas?

A

TB, Klebsiella patients

92
Q

What patients are at risk for Angioinvasive Aspergillosis?

A

Immunocomprimised

Kidney failure, ring-enhancing lesions on brain, Endocarditis, necrosis around nose due to spread to paranasal sinuses

Treat with ampho B, surgical debridement as necessary

93
Q

Aspergillosis, except for the most severe form, is treated with:

A

“conazoles” ie Voriconazole

94
Q

Orthomyxovirus is responsible for what disease?

A

Influenza BITCHES
3 strains - A, B, C
8 segments –> relates to how the virus can mutate

95
Q

What is the taxonomy or orthomyxovirus?

A

RNA
(-) sense
Enveloped

96
Q

What is unique about orthomyxovirus as an RNA virus?

A

It’s the only RNA virus that replicates in the nucleus

97
Q

Influenza A is responsible for what kinds of outbreaks?

A

PANdemics and epidemics

Pandemics - antigenic SHIFT - changes in Hs and Ns on surface antigens to form new viruses (reassortment)

Epidemics - antigenic DRIFT - point mutations

98
Q

Influenza B is responsible for what kinds of outbreaks?

A

Just epidemics

Epidemics - antigenic DRIFT - point mutations

99
Q

How does Tamiflu work?

A

NA inhibitor
Prevents NA from breaking viral babies free from sialic acid;
must give early in the course of the disease

100
Q

How is influenza (orthomyxovirus) transmitted?

A

Respiratory droplets

101
Q

What vaccines are available for influenza (orthomyxovirus)

A

Trivalent - 2A and 1B strains
Quadrivalent - 2A and 2B strains
can receive >6 months of age

102
Q

What is the major complication of influenza (orthomyxovirus)?

A

Pneumonia, often by Staph aureus or Strep pneumo;

Guillain-Barre syndrome (high protein, low WBC in CSF)

103
Q

What is the taxonomy of Paramyxovirus?

A

Single strand
RNA virus
(-) sense
Replicates in the cytoplasm

104
Q

Why is the MMR vaccine not indicated for pregnant patients?

A

It’s live-attenuated

105
Q

Associate the 4 C’s: Cough, Coryza, Koplick spots and Conjunctivitis, with what viral illness?

A

Measles (Rubeola)
caused by Paramyxovirus
4 days of that stuff, followed by a maculopapular rash that becomes confluent and is itchy, Starts on face and moves down the body

106
Q

What are the complications of measles (rubeola)?

A

Pneumonia

SSPE - subacute sclerosing panencephalitis - can happen years later, no tx for it

107
Q

What virulence factors does paramyxovirus-rubeola have?

A

Hemagglutinin
Fusion proteon –> multinucleated giant cells –> syncytia
**Vitamin A admin reduces virulence factors and complications

108
Q

Mumps is caused by what kind of virus?

A

Paramyxovirus

109
Q

RSV is caused by what kind of virus?

A

Paramyxovirus

110
Q

Croup is caused by what kind of virus?

A

Paramyxovirus

111
Q

Hemagglutinin, Fusion Protein and Neuraminidase are virulence factors of what paramyxovirus?

A

Mumps

112
Q

Where does mumps replicate?

A

Parotid glands

Can cause orchitis and meningitis

113
Q

What is the most common cause of pneumonia and bronchiolitis in infants?

A

RSV

Infiltrates on CXR

114
Q

What is the only virulence factor of RSV?

A

Fusion protein (syncytia formation)

115
Q

Seal bark and inspiratory stridor are characteristic of what paramyxoviral infection?

A

Croup aka laryngotracheobronchitis

116
Q

A pediatric patient with Croup would likely have a CXR showing:

A

Steeple sign - narrowing of subglottal region

117
Q

Croup has what virulence factors?

A

Croup is a paramyxovirus - parainfluenza:

HA, NA, fusion protein

118
Q

What is the gram (-) rod is responsible for causing whooping cough (100 days cough)?

A

Bordatella pertussis

Highly contagious - transmission via respiratory droplets

119
Q

Bloodwork of a patient with whooping cough would show what abnormality?

A

Leukocytosis

120
Q

How does the bordatella pilus work to infect cells?

A

Filamentous hemagglutinin attaches, pertussis toxin exotoxin causes ciliary stasis and death of ciliated cells

121
Q

Which bordatella vaccine is used in the U.S.?

A

Acellular (DTaP), has a shorter window of effectiveness than the killed version (used abroad)

122
Q

Bordatella pertussis is treated with:

A

Macrolides

123
Q

Name the pathogen:
Gram (-)
Coccobacilliary
Grows on chocolate agar with factors V and X

A

Haemophilus influenzae

124
Q

How is Haemophilus influenzae transmitted?

A

Aerosol

125
Q

Pneumonia, Epiglottitis, Meningitis and Otitis media are three presentations of what gram (-) bacterium?

A

Haemophilus influenzae

126
Q

What patient population is more at risk for Haemophilus influenzae infection?

A

Splenectomized patients (SCD) - can develop sepsis or septic arthritis

127
Q

The Haemophilus influenzae vaccine covers what type?

A

Type B (the cause of meningitis, encapsulated)

128
Q

What are the symptoms of epilglottitis caused by Haemophilus influenzae?

A

Inspiratory stridor;
“cherry red epiglottis;”
drooling

129
Q

What is indicated for close contacts of a patient with Haemophilus influenzae?

A

Rifampin prophylaxis