Fiser.05.Infection Flashcards
1
Q
What is the MCC of immune deficiency?
A
malnutrition leading to infection
2
Q
What is the microflora in the stomach?
A
virtually sterile, some yeast, some GPCs
3
Q
what is the microflora of the distal small bowel (include concentrations)
A
10^7 bacteria with GPCs, GNRs, and GPRs
4
Q
What is the microflora of the proximal small bowel (include concentrations)
A
10^5 bacteria, mostly GPCs
5
Q
what is the microflora of the colon? (include concentrations)
A
10^11 bacteria, almost ALL anaerobes, some GNRs and GPCs
6
Q
what is the MC anaerobic bacteria in the colon?
A
Bacteroides fragilis
7
Q
What is the ratio of aerobic to anaerobic bacteria in the colon?
A
1:1000
8
Q
What is the MC aerobic bacteria in the colon?
A
E. coli
9
Q
What is the MC organism in the GI tract?
A
anaerobic bacteria
10
Q
What is the MCC of fever 48 hours postop?
A
atelectasis
11
Q
What is the MCC of fever 48hrs - 5 days postop?
A
UTI
12
Q
What is the MCC of fever > 5 days postop?
A
wound infection
13
Q
What is the MCC of gram negative sepsis?
A
E. coli
14
Q
What is the endotoxin released by E. coli and how does it trigger sepsis?
A
the endotoxin = lipopolysaccharide lipid A –> triggers macrophages to release TNF-alpha –> complement activation –> coagulation cascade activation
15
Q
what is the insulin / glc picture in EARLY gram negative sepsis and why?
A
low insulin and elevated glucose 2/2 impaired utilization
16
Q
What is the insulin / glucose picture in late gram negative sepsis and why?
A
elevated insulin and elevated glucose 2/2 insulin resistance
17
Q
when does hyperglycemia present in a septic patient?
A
just before the patient becomes clinically septic
18
Q
What is the optimal glucose level in a septic patient?
A
100-120 mg/dL
19
Q
what is the PO/IV regimen for C dif colitis? What about abx already on board?
A
PO: vanc or Flagyl +/- Lactobacillus; IV: Flagyl for other abx, discontinue or change
20
Q
What percentage of abdominal abscesses have anaerobes?
A
90%
21
Q
What percentage of abdominal abscesses have aerobes AND anaerobes?
A
80%
22
Q
How far out postop do abdominal abscesses present?
A
7-10 days postop
23
Q
what is the treatment for abdominal abscesses?
A
drainage
24
Q
what SIX underlying conditions merit the use of antibiotics for patients with abdominal abscesses?
A
DM; cellulitis; clinical S/Sx of sepsis; fever; elevated WBC; bioprosthetic hardware (mech valve, hip replacement)
25
what is the rate of SSI with a CLEAN case?
2% (ex: inguinal hernia repair)
26
what is the rate of SSI with a CLEAN-CONTAMINATED case?
3-5% (ex: elective colon resection with a prepped bowel)
27
what is the rate of SSI in a CONTAMINATED case?
5-10% (ex: GSW to the colon with repair)
28
what is the rate of SSI in a GROSSLY CONTAMINATED case?
30% (ex: abscess)
29
How do you define a CLEAN case? Give examples
uninfected, no inflammation; respiratory/GI/GU tracts are not entered; closed primarily ex: exlap, mastectomy, neck dissection, thyroid, vascular, hernia, splenectomy
30
How do you define a CLEAN-CONTAMINATED case? Give examples
respiratory/GI/GU tracts are entered under CONTROLLED conditions, no unusual contamination. Ex: chole, SBR, whipple, liver txp, gastric surgery, bronch, colon surgery
31
How do you define a CONTAMINATED case? Give examples
open fresh, accidental wounds; major break in sterile technique; gross spillage from GI tract; acute non-purulent inflammation. Ex: inflamed appy; bile spillage in chole; diverticulitis; rectal surgery; penetrating wounds
32
How do you define a DIRTY case? Give examples
old traumatic wounds with devitalized tissue; existing infection or perforation; organisms present BEFORE procedure. ex: abscess I&D, perforated bowel, peritonitis, wound debridement, positive cultures preop
33
Why are prophylactic abx administered during surgery?
prevent SSI
34
What is the stop time for prophylactic abx for regular and cardiac cases?
regular cases: abx stop within 24 hours of the end of operation time. cardiac cases: abx stop within 48 hours of the end of operation time
35
What is the MCC of SSI? (organism)
staph aureus
36
is staph aureus coagulase positive or negative?
coagulase positive
37
is staph epidermidis coagulase positive or negative?
coagulase negative
38
what is the function of the EXOSLIME released by the staph spp?
exopolysaccharide matrix
39
what is the MC GNR in SSI?
E. coli
40
What is the MC anaerobe in SSI?
Bacteroides fragilis
41
if you isolate B. fragilis from a surgical wound, what are THREE things on your Ddx and why?
necrosis / abscess b/c B. fragilis only grows in a low redox state; translocation from the gut
42
What [x] of bax is needed to cause a wound infection?
\> or = 10^5 bax are needed for a wound infection
43
What can lower the [x] of bax needed to cause a wound infection?
less than 10^5 bacteria are needed to cause a wound infection if a foreign body is present
44
Name five risk factors for wound infection
long operations; hematoma/seroma formation; chronic disease (COPD, renal failure, liver failure, DM); malnutrition; immunosuppression
45
What are the pathogens (2) and MOA of invasive soft tissue infection?
Causes: clostridium perfringens & beta hemolytic strep. MOA: produces exotoxins
46
What are two surgical site infections that can occur within 48 hours of the procedure
1) injury to the bowel with leak; 2) invasive soft tissue infection with C. perfringens / Beta-hemolytic strep
47
What is the most common postop infection?
UTI
48
What is the biggest risk factor for UTI? Which bacteria is the MCC?
biggest risk factor: Foley; MCC: E. coli
49
What is the MCC of postop infectious death?
Nosocomial PNA
50
What are the two underlying causes (clinical) of nosocomial PNA?
number of vent days; duodenal aspiration
51
What are the 2 MCC (bax) of ICU nosocomial PNA
1) Staph aureus; 2) Pseudomonas
52
What is the #1 class (bax) of organisms in ICU PNA?
GNRs
53
What are the 3 MCC of line infections?
1) staph epidermidis; 2) stap aureus; 3) yeast
54
What percent of CVLs are salvaged with antibiotics?
50%
55
Which organism is least likely to be salvaged with antibiotics 2/2 CVL infection?
much less likely with yeast infections
56
how many CFUs indicate a CVL infection?
\> 15 CFUs
57
What is the management of a CVL that shows S/Sx of infection?
discontinue the line and either move it to a new site or use PIVs
58
Name the 3 MCC of NSTIs
1) group A beta hemolytic strep; 2) Clostridium perfringens; 3) mixed organisms
59
what are the two underlying risk factors for NSTI?
immunocompromised; poor blood supply
60
name 6 s/sx a/w NSTI
pain out of proportion to skin exam; WBC \> 20; thin, gray drainage; skin blistering / necrosis; induration / edema; crepitus / soft tissue gas on XR all +/- sepsis
61
What is the MCC of necrotizing fasciitis? (pathogen)
beta hemolytic group A strep, some polymicrobials
62
What are the skin changes (over time) seen with necrotizing fasciitis? What are 2 other S/Sx on skin exam?
overlying skin is normal in early stages --\> pale red --\> purple --\> blisters / bullae. Eventually will lead to crepitus with thin-gray & foul smelling fluid
63
Why does necrotizing fasciitis move so quickly?
secretes exotoxin; moves along fascial planes
64
What are the abx and surgical tx for necrotizing fasciitis
high dose PCN, can make it broad spectrum because it can sometimes be polymicrobial. Surgical tx: early debridement
65
What is the MOA of clostridium perfringens in skin infections?
produces alpha toxin
66
why is necrotic tissue a/w C. perfringens infection?
necrotic tissue = reduced oxidation and reduction potential; sets up environment for clostridium perfringens
67
What skin findings are seen with C. perfringens infection? Name three other physical exam findings
May not have changes in skin with deep infections. You get pain out of proportion to exam; myonecrosis; and gas gangrene
68
What NSTI organism is a/w farming injuries?
Clostridium perfringens
69
What does the Gram Stain show with C. perfringens
GPRs without WBCs
70
What is the abx and surgical treatment for NSTI 2/2 C. perfringens
high dose PCN; early debridement
71
What is Fournier's gangrene and 3 MC underlying organisms?
severe infection of the perineum and scrotum 2/2 GPCs, GNRs, and anaerobes
72
What is the treatment for Fournier's gangrene?
Early debridement; preserve testicles if possible; antibiotics
73
Name 5 indications (clinical or culture) for fungal coverage
positive fungal blood cultures; positive two sites other than blood; +1 site with severe symptoms; endoopthalmitis; patients on prolonged antibacterial abx and fail to improve
74
What are two presentations of Actinomyces infection?
pulmonary symptoms (MC); tortuous abscesses in cervical, thoracic, and abdominal areas
75
What is the treatment for actinomyces infection
drainage; penicillin G (because not a true fungus)
76
What are the MC presentations of Nocardia infection?
pulmonary symptoms; CNS symptoms
77
what is the treatment for nocardia infection? (2)
drainage; sulfonamides (Bactrim) because not a true fungus
78
What is the MC presentation of Candida infection?
Respiratory (common inhabitant of respiratory tract)
79
What are the two treatments for candida infection?
fluconazole (some candida resistant); anidulafungin (Eraxis) for severe infections
80
What is the tx for aspergillosis
voriconazole
81
what is the MC presentation of histoplasmosis?
pulmonary symptoms
82
where in the US is histoplasmosis endemic?
Mississippi and Ohio River Valleys
83
What is the presentation of Cryptococcus infection?
CNS sx
84
What is the MC comorbidity a/w cryptococcus infection?
AIDS
85
What is the treatment for cryptococcus infection?
liposomal amphotericin
86
what is the MC presentation of coccidiodomycosis?
pulmonary symptoms
87
Where in the US is coccidiodomycosis endemic?
Southwest US
88
What is the treatment for coccidiodomycosis?
liposomal amphotericin
89
what is the [x] of protein found in peritoneal fluid in primary spontaneous bacterial peritonitis (SBP)?
low protein (\< 1g/dL) = risk factor
90
What are the three MCC (pathogens) of primary SBP (include prevalence of each)
Monobacterial: 50% E. coli; 30% Strep; 10% Klebsiella
91
What is the underlying pathophysiology of primary SBP?
due to reduced host defenses; intrahepatic shunting; impaired bacteriocidal activity in ascites. NOT due to transmucosal migration
92
What gram stain finding is diagnostic of primary SBP?
\> 500 PMNs per cc
93
What are peritoneal culture findings in primary SBP?
fluid cultures are often negative
94
what is the treatment for primary SBP?
ceftriaxone (Rocephin) or other third generation cephalosporins
95
What antibiotics can be used for primary SBP prophylaxis?
fluoroquinolones. Ex: ciprofloxacin (Cipro), gemifloxacin (Factive), levofloxacin (Levaquin), moxifloxacin (Avelox), norfloxacin (Noroxin), and ofloxacin (Floxin).
96
With primary SBP, what two clinical scenarios are indications to rule out another intraabdominal source?
patients is not improving on antibiotics OR fluid cultures are polymicrobial
97
Can you perform a liver transplant in a patient with active primary SBP?
nope
98
What is the pathophysiology of secondary bacterial peritonitis?
intraabdominal source: implies perforated viscus
99
What are the 3 MCC (pathogens) of secondary bacterial peritonitis?
Polymicrobial - bacteroides fragilis; E. coli; enterococcus
100
is primary SBP monobacterial or polymicrobial?
monobacterial
101
is secondary bacterial peritonitis monomicrobial or polymicrobial?
polymicrobial
102
what is the treatment for secondary bacterial peritonitis?
antibiotics; laparotomy to find intraabdominal source
103
what is the HIV exposure risk from an HIV positive blood transfusion?
70%
104
What is the HIV exposure risk for vertical transmission?
30%
105
What is the HIV exposure risk for a needle stick from an HIV-positive patient?
0.3%
106
What is the HIV exposure risk for mucous membrane exposure?
0.1%
107
How long after HIV exposure does seroconversion occur?
6-12 weeks
108
What is the MOA of AZT (zidovudine)?
reverse transcriptase inhibitor
109
What is the MOA of ritonavir?
protease inhibitor
110
Why should you take AZT and ritonavir after HIV exposure? When should they be administered?
reduce the risk of seroconversion; should be administered within 1-2 hours of exposure
111
What is the MCC of laparotomy in HIV patients?
opportunistic infections (especially CMV infection = MCC of laparotomy)
112
what is the 2nd MCC of laparotomy in HIV+ patients
neoplastic disease
113
What is the MC intestinal manifestation of AIDS and how does it present?
CMV colitis p/w bleeding & perforation
114
what is the MC neoplasm in AIDS patients?
Kaposi's sarcoma
115
Where are the two MC locations for lymphoma in HIV patients?
1) stomach; 2) rectum
116
What is the MC subtype of lymphoma in HIV patients?
non-Hodgkins B-cell
117
How do you treat lymphoma in HIV patients?
chemotherapy +/- surgery (if significant bleeding or perforations)
118
Are upper or lower GI bleeds MC in HIV patients?
LGI bleeds more common
119
what are the 2 MCC of UGI bleeding in HIV patients?
1) Kaposi's sarcoma; 2) lymphoma
120
what are the 3 MCC of LGI bleeds in HIV+ patients?
1) CMV; 2) bacterial; 3) HSV
121
what are the normal, symptomatic, and opportunistic CD4 counts in HIV patients?
normal: CD4 800-1200; symptomatic: CD4 300-400; opportunistic infections: CD4 \< 200
122
What is the rate of hepC transmission via blood transfusion?
0.0001% / unit
123
What is the prevalence of HepC?
1-2%
124
What percent of HepC patients have chronic infection?
60%
125
What percent of HepC patients develop cirrhosis?
15%
126
What percent of HepC patients develop hepatocellular carcinoma?
1-5%
127
Is fulminant hepatic failure in Hep C patients common?
No, its rare
128
What med can help prevent cirrhosis in HepC patients?
interferon
129
What is the treatment for brown recluse spider bites?
first line: dapsone; treat by resection with skin grafts for large ulcers later
130
What are the four MCC of acute septic arthritis
1) Gonococcus; 2) Staph; 3) H. influenzae; 4) strep
131
What is the treatment for acute septic arthritis
drainage; third generation cephalosporins + vancomycin --\> narrow with cultures
132
What are the four MCC of diabetic foot infections?
MIXED CAUSES staph; strep; GNRs; anaerobes
133
What organism is only found in human bites? What can it cause?
Eikenella --\> can cause permanent joint injury
134
What organism is found in cat & dog bites?
Pasteurella multocida
135
What antibiotics do you use for dog/cat/human bites?
Augmentin (broad spectrum - amoxicillin/clavulanic acid)
136
What abx do you use for diabetic foot infections?
Unasyn (broad spectrum - ampicillin / sublactam)
137
what are the two MCC (bax) of impetigo?
staph / strep
138
what are the two MCC (bax) of erysipelas?
staph / strep
139
what are the two MCC (bax) of cellulitis?
staph/strep
140
what are the two MCC (bax) of folliculitis?
staph/strep
141
What are the 2 MCC (bax) of a furuncle/boil?
Staph epidermidis; staph aureus
142
what is the treatment for a furuncle
drainage +/- abx
143
What is a carbuncle?
a multiloculated furuncle
144
What are the 2 MCC of PD catheter infections?
staph aureus; staph epidermidis
145
What are the most challenging subtype of PD catheter infections to treat?
fungal
146
what is the tx for PD catheter infections? (3)
intraperitoneal vanc + gent; increase dwell time; intraperitoneal heparin
147
when is the removal of the PD catheter indicated for PD catheter infections? (4)
peritonitis that lasts 4-5 days; all fungal, TB, and pseudomonas infections
148
What is the treatment for PD catheter infection a/w fecal peritonitis?
laparotomy to find perforation
149
name three risk factors for sinusitis
NGT; intubation; severe facial fx
150
what is the underlying cause (bax) of sinusitis?
usu polymicrobial
151
what are the CT head findings a/w sinusitis?
air-fluid levels in the sinuses
152
what is the tx for sinusitis?
broad-spectrum abx; +/- percutaneosly tap the sinus if systemic illness
153
why do you use clippers instead of razors preop?
reduce the risk of wound infection
