Pathophys: ID Flashcards
1
Q
3 most common causes of bacterial meningitis
A
S. pna
H. flu
N. meningitis
2
Q
Meningitis: terminal complement pathway deficiency
A
NM
3
Q
Meningitis: cochlear implants/CSF leak
A
S. pna
4
Q
Meningitis: inability to opsonize
A
S. pna
H. flu
5
Q
Meningitis: CS use
A
Listeria & Crypto
6
Q
Meningitis: HIV
A
S. pna, Listeria, Crpyto
7
Q
Meningitis: exposure to others with meningitis
A
H. flu, NM
8
Q
Meningitis: otitis media
A
S. pna, H. flu
9
Q
Meningitis belt of N. sub-Saharan Africa
A
NM
10
Q
Pathogenesis of N. meningitis meningitis
A
Oropharynx colonization
11
Q
Pathogenesis of S. pna meningitis
A
Nasopharynx, skull fracture, PNA, otitis media
12
Q
Pathogenesis of H. flu meningitis
A
Nasopharynx
13
Q
Pathogenesis of L. monocytogenes meningitis
A
Food; placenta
14
Q
Pathogenesis of Coag-negative staph meningitis
A
Foreign body; CSF shunt
15
Q
Pathogenesis of S. aureus meningitis
A
Foreign body, spread from bacteremic source, epidural abscess
16
Q
Gram-positive diplococci, bile soluble, alpha hemolysis, catalase positive
A
S. pna
17
Q
Gram-negative diplococci; LOS
A
NM
18
Q
Gram-negative pleomorphic; ox+, chocolate agar/hemin, NAD
A
H. flu
19
Q
Gram-positive rod, motile; beta-hemolytic
A
LM
20
Q
Which pathogen has the worst prognosis in bacterial meningitis?
A
S. pna
21
Q
DDX for bacterial meningitis
A
Viral, fungal, TB, encephalitis (W. Nile), SA bleed
22
Q
Major risk factors for meningitis
A
- Functional or anatomic asplenia
- Chronic immunodeficiency: HIV/nephrotic/C1-4 deficiency
- Heart/Lung disease
- CSF leak
- Cochlear implant
- DM
23
Q
Pili & adhesion factors help with colonization. Which meningitis organisms have these?
A
NM, H. flu - Pili
S. pna - Adhesion
24
Q
The main pharmacotherapy principle in treating bacterial meningitis is:
A
ABX to penetrate BBB at high levels
25
Vaccines are available for which causes of meningitis?
H. flu B, S. pna
26
Major post-infection manifestations of Group A Strep infection
1. PSGN
2. Scarlet fever
3. Acute rheumatic fever
4. PANDAS
5. Local suppurative extension: abscess, OM, necrotizing fascitis
27
Skin infection: cat bite
Pasturella
28
Skin infection: dog bite
Capnocytophaga
29
Skin infection: salt water
Vibrio vulnificus
30
Skin infection: fresh water
Aeromonas
31
Skin infection: hot tub folliculitis/neutropenia/wet wounds
Pseudomonas
32
Skin infection: domestic animal (vets)
Erysipelothrix rhusopathaie
33
Skin infection: IC host
Cryptococcus
34
DDX skin infection
1. Abscess
2. Necrotizing fasciitis
3. Bursitis over joints
4. DVT
5. Contact dermatitis
6. Gout
35
Etiology of most cellulitis
Beta-hemolytic strep, Staph
36
What is the difference between furuncle and carbuncle?
Furuncle: hair follicle
Carbuncle: multiple hair follicles
37
Spider bite papule, erythema, induration, fever and hypotension; bone/joint/CNS/lung/heart valve involvement
Staph aureus
38
3 Staph aureus toxins and 1 Leukocidin
Heat-stable food toxin
TSST-1: TSS
Exfoliatoxin: scalded skin/neonates
PVL: leukocyte destruction and tissue necrosis
39
What is the technical definition of nosocomial MRSA?
Occurs after 48 hours admission; or in the community up to 12 months following hospitalization
40
3 major microbes of skin/soft tissue
S. aureus, GAS, GBS
41
2 y.o. female febrile and irritable with eye-discharge in the AM. Bug?
H. flu
42
3 major bugs associated with otitis media. Comment on viral causes.
S. pna
H. flu (non-typable)
Moraxella catarrhalis
2/3: combined viral & bacterial
43
Major risk factors for otitis media
1. 6-18 months
2. Family history
3. Day care, smoking, lack of breast feeding
4. First nations people of N. America, Australia
44
T/F Approximately 2/3 cases of otitis media are combined viral/bacterial in origin
True
45
Complications of otitis media
Hearing loss, balance and motor problems
Tympanic membrane rupture
Extension to adjacent structures (mastoiditis)
CNS infection
46
Comment on the 4 categories of rhinosinusitis: acute, subacute, chronic, recurrent
Acute: < 4 weeks
SA: 4-12 weeks
Chronic: >12 weeks
Recurrent: >4 with resolution
47
On an X-ray, pus shows up as:
Air-fluid level
48
Most commonly, acute sinusitis is viral/bacterial in origin
Viral (rhino, influenza, parainfluenza) with possible bacterial secondary infection (S. pna, H. flu, M. catarrhalis)
49
Risk factors for sinusitis
Allergic rhinitis, obstruction, odontogenic infection, intranasal cocaine, impaired mucociliary clearance, swimming, IC host, children in day care
50
Sinusitis complicated by bacterial infection...
Persistent symptoms (purulent D/C, facial pain) after 10 days, but less than 30
Severe symptoms with fever, purulent D/C: 3-4 days
Worsening symptoms after initial improvement
51
Complications of sinusitis.
| Urgent referral is required for...
Periorbital cellulitis, OM, CNS infection, deep neck infection; urgent referral for: diplopia, decreased LOC, meningismus, proptosis
52
CAP: exposure to parrots (bug)
Chlamydophilia psittaci
53
CAP: exposure to pregnant (parturient animals) (bug)
Coxiella burnetti
54
CAP: exposure to water vapor & soil (bug)
Legionella
55
CAP: classic presentation
| Elderly? Young
Fever, cough, chest pain, SOB
Elderly: confusion, low temp
Young: fever, irritability
56
CAP: mucopurulent sputum associated with rust-colored sputum
S. pna
57
CAP: risk factors
Decreased LOC, smoking, ETOH, >65 yo, Postviral, CHF, esophageal dysmotility; mechanical obstruction, clearance problems, IC
58
CAP: 3 most common bugs post-viral
S. pna
H. flu (non-typable)
S. aureus (including CA-MRSA)
59
CAP: common in elderly (bug)
C. pna
60
CAP: common with crowding, children, young adults (bug)
M. pna
61
CAP: common in ETOH-ics (bug)
Klebsiella
62
CAP: common in IS, chronic structural lung disease (bug)
Pseudomonas
63
CAP: to grow Legionella, what medium must be used? It it an IC or EC organism?
IC organism: buffered charcoal yeast
64
Legionella can cause 2 sydromes
1. Pontiac fever
| 2. PNA
65
Classic symptoms of Legionella PNA.
Findings on sputum GS
Failure to respond to: which ABX?
Diagnosis based on:
GI complaints, fever > 40, hyponatremia, hematuria
GS: 3+ WBC, but no organisms
Failure to respond to beta-lactams
Urinary Legionella Ag
66
CAP: IC pathogen with elementary and reticulate body
Chlamydophilia
67
CAP: Psittacosis diagnosis is based on...
Serology; highly infectious organism in cell culture
68
HAP: Pathogenesis of Pseudomonas PNA
Micro-abscesses with hemorrhage and necrosis of alveolar septae
69
Several different infections associated with Pseudomonas
1. Hot tub folliculitis
2. Puncture osteomyelitis
3. Burn infections
4. Bacteremia
5. Malignant otitis externa [diabetic patients]
6. Post-op CNS infection
7. Endocarditis (IVDU/prosthetic valves)
70
Malignant otitis externa is caused by... in what patients?
Pseudomonas (DM)
71
What drug turns urine orange?
Rifampin
72
First and second most common ID deaths in the world
1. HIV
| 2. TB
73
The 4 possible outcomes of TB infection
1. Eradication
2. Latent infection
3. Primary disease
4. Reactivation
74
What percentage of people infected with TB will develop active disease?
10%
75
Primary TB infection occurs when a tubercle forms. What is a Ghon complex?
Granuloma: macrophages, monocytes, neutrophils with involvement of lymph nodes
76
The key factor for re-activation of TB is...
Host immunity: AIDS/HIV; Transplant, etc.
77
Who is more likely to reactivate TB: young or old?
Young
78
DDX TB
Other mycobacteria, sarcoidosis, endemic fungal infection, Q fever, Lymphoma, foreign body vasculitis from IVDU, HIV/AIDS
79
Describe some examples of miliary TB
Meningitis, scrofula, hepatitis, bowel involvement, Pott's disease, mycotic aneurysm, adrenal involvement with AI
80
Other mycobacterial infection...
Leprosy: lepromatous, multibacillary
81
Mycobacterium: LAD in children
M. scrofulaceum
82
Mycobacterium: skin lesions by direct inoculation
M. marinum
83
Mycobacterium: infection in lung in elderly/AIDS CD4 <50
MAC
84
Modified Duke's criteria for endocarditis: Major
1. Persistent + BC with typical EC organism
2. + TEE; new valvular regurgitation
3. Serologic evidence Coxiella burnetti infection
85
Modified Duke's criteria for endocarditis: Minor
1. Predisposition: prosthetic valve, IVDU
2. Fever
3. Vascular: emboli, aneurysm, Janeway
4. Immunologic phenomena: GN, Osler's, Roth Spots, RF
5. Intermittent bacteremia/fungemia
86
Is RF elevated in bacterial endocarditis? Are RBC casts present?
Yes & yes
87
3 major organisms of bacterial endocarditis (and others)
1. S. aureus
2. S. viridans
3. Enterococci
Culture negative, Coag negative, S. bovis, HACEK, fungi
88
Endocarditis: most common reason of death
Heart failure, also valve ring abscess; emboli; metastatic abscesses
89
Major causes of infectious hepatitis
A, B, C, CMV, EBV, Leptospira (Weil's disease)
90
Non-infectious causes of hepatitis
AI, ETOH, Tylenol, Mushroom
91
Does HAV have a carrier state?
No
92
HAV belongs to which virus family?
Picorna-virus
93
Most important risk factor for HAV in US?
International travel
94
HBV has the highest risk of becoming chronic for young or old people?
Young (90% perinatal); 5% adults
95
HBV, HCV, HIV: which is most easily transmitted by blood?
HBV
96
HBV belongs to which virus family?
Hepadna
97
The full HBV viral particle is called…
Dane particle
98
Does HBV utilize reverse transcription? Which drugs does that mean we can use to treat HBV?
Yes; Tenofovir (HIV RT inhibitor)
99
Extra-hepatic manifestations of HBV
Polyarteritis nodosa, Membranous nephropathy, Aplastic anemia
100
LTM effects of HBV on liver? Factors associated with poorer prognosis
Cirrhosis, HCC
| * prolonged HBeAg+ stage, ETOH, HDV
101
HBSAg
Surface Ag (Vaccine or Infection = Ab)
102
HBCAg
Core antigen: infection (Ab = past infection)
103
HBeAg
Full virus particle in blood (high levels)
104
HBVDNA
HBV activity: marker of treatment effectiveness
105
Most common indication for LT in US
HCV
106
Risk factors HCV
IVDU, blood, jail, poor SES
107
HCV virus family (and other viruses)
Flavi: Dengue, WNV, Yellow fever, Japanese encephalitis)
108
Does HCV have an intermediate DNA genome?
No: no RT
109
Host factors associated with HCV chronic infection
IL-28B: CC -- better response to therapy
40-55: more rapid progression
HIV, Fatty liver, ETOH: greater risk of progression
110
Best predictor of progression of HCV…
Liver bx [or fibroscan]: +/- fibrosis
111
Extra-hepatic manifestations HCV
Mixed cryoglobulinma, lymphoma, MPGN, porphyria, DM
112
3 major manifestations of AIDS
PCP, esophageal candida, HIV wasting
113
Stage B HIV Symptoms
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