Infection Flashcards
(169 cards)
1
Q
What is the most common immune deficiency that leads to infection?
A
Malnutrition
2
Q
What type of microflora inhabit the stomach?
A
It’s virtually sterile with some GPC and some yeast
3
Q
What type of microflora inhabit the proximal small bowel?
A
10^5 bacterial, mostly GPCs
4
Q
What type of microflora inhabit the distal small bowel?
A
10^7 bacteria, GPCs, GPRs, GNRs
5
Q
What type of microflora inhabit the colon?
A
10^11 bacterial, almost all anaerobes with some GNRs, GPCs
6
Q
What is the most common organism in the GI tract?
A
Anaerobes
7
Q
Why do anaerobes need a low-oxygen environment?
A
Lack superoxide dismutase and catalase, making them vulnerable to oxygen radicals
8
Q
What is the most common anaerobe in the colon?
A
Bacteriodes fragilis
9
Q
What is the most common aerobic bacteria in the colon?
A
E. Coli
10
Q
What is the most common fever source within 48 hours post op?
A
Atelectasis
11
Q
What is the most common fever source 48 hours - 5 days post-op?
A
UTI
12
Q
What is the most common fever source >5 days post op?
A
Wound infection
13
Q
What it’s he most common bacterial to cause gram negative sepsis?
A
E. Coli
14
Q
What do gram negative bacteria contain that leads to sepsis?
A
Endotoxin (lipid A) which triggers release of TNF-a (triggers inflammation), activates complement, and activates coagulation cascade
15
Q
What is the optimal glucose level in septic patients?
A
80-120 mg/dL
16
Q
When does hyperglycemia usually occur in septic patients?
A
Just before the patient becomes clinically septic
17
Q
What are the insulin and glucose levels usually in early gram-negative sepsis?
A
Decreased insulin, increased glucose (impaired utilization)
18
Q
What are the insulin and glucose levels usually in late gram-negative sepsis?
A
Increased insulin, increased glucose secondary to insulin resistance
19
Q
What are the symptoms of Clostridium difficult colitis (pseudomembranous colitis)?
A
Foul-smelling diarrhea, usually seen in nursing home or ICU patients
20
Q
How to diagnose C. Diff?
A
ELISA for toxin A
21
Q
What lab value is often extremely elevated in patients with C. Diff?
A
Elevated WBCs often in the 30-40s
22
Q
What is the treatment for C. Diff?
A
Oral vancomycin, oral flagyl, or IV flagyl
IVF and stop other antibiotics
Lactobacillus can also help
23
Q
How to treat C. Diff in pregnant person?
A
Oral vancomycin because no systemic absorption
24
Q
What is the treatment of fulminant (severe sepsis, perforation) pseudomembranous colitis?
A
Total colectomy with ileostomy
25
How are abscesses treated?
Drainage
26
After how long post-op do abscesses form?
7-10 days
27
In what type of patients are antibiotics used for an abscess?
Diabetes, cellulitis, clinical signs of sepsis, fever, or who have bioprosthetic hardware (mechanical valves, hip replacements)
28
Bacterial component of abdominal abscesses?
90% have anaerobes
| 80% have anaerobes and aerobes
29
What surgical wound is considered clean?
Hernia
30
What are some examples of clean contaminated wounds?
Elective colon resection with prepped bowel
31
What is a gross contaminated wound?
An abscess
32
Why are prophylactic antibiotics given pre op?
To prevent surgical site infections
33
When should prophylactic antibiotics be given pre-op?
Within 1 hour of incision
34
When should prophylactic antibiotics be stopped post op?
Stop within 24 hours of end operation time
| Except cardiac, which is stopped within 48 hours
35
What is the most common organism overall in surgical site infections?
Staph aureus — coagulase-positive
36
What is the most common GNR in surgical wound infections?
E. Coli
37
What is the most common anaerobe in surgical wound infections?
B. Fragilis
38
What does a surgical wound infection with B fragilis indicate?
Translocation from the gut
39
How much bacteria is necessary for a wound infection?
10^5
40
When is less bacteria needed to create a wound infection?
When there is a foreign body present
41
What are the risk factors for wound infection?
Long operations, hematoma or sermon formation, advanced ago, chronic disease (COPD, renal failure, liver failure, DM), malnutrition, immunosuppressive drugs
42
What would cause surgical infections within 48 hours of procedure?
Injury to bowel with leak
| Invasive soft tissue infection — Clostridium perfringens and beta-hemolytic strep (produce exotoxins)
43
What is the most common infection in surgery patients?
UTI
44
What is the biggest risk factor for UTI in surgery patients?
Urinary catheters
45
What is the MCC of UTI in surgical patients?
E. Coli
46
What is the leading cause of infectious death after surgery?
Nosocomial pneumonia
47
What are the most common organisms in ICU pneumonia?
1) S. Aureus 2) pseudomonas 3) E. Coli
48
What class fo organisms is most common in ICU pneumonia?
GNRs
49
What increases risk of nosocomial pneumonia in surgical patients?
Length of ventilation
| Aspiration from duodenum thought to have a role
50
What are the three most common bacteria in line infections?
1. S. Epidermidis
2. S. Aureus
3. Yeast
51
What location for central lines has the highest risk of infection? Lowest risk?
Highest risk is femoral line
| Lowest risk is subclavian line
52
What is the salvage rate for lines during infection, when giving antibiotics?
50%
53
What decreases the line salvage rate when infected?
If the bug is yeast
54
What are the most common organisms to cause necrotizing soft tissue infections?
Beta-hemolytic Steptococcus, C. Perfringes, or mixed organisms
55
In what types of patients do necrotizing soft tissue infections usually occur?
Immunocompromised and patients with poor blood supply
56
How long after injury or post op does it take for necrotizing soft tissue to occur?
Quickly, within hours
57
What are the signs and symptoms of necrotizing soft tissue infections?
Pain out of proportion to skin findings (infections tarts deep to the skin), mental status change, WBCs>20, thin gray drainage that is foul-smelling, can have skin blistering/necrosis, induration and edema, crepitus or soft tissue gas on x-ray, can be septic
58
What organism usually causes necrotizing fasciitis?
Beta-hemolytic group A strep or MRSA. Have exotoxin
59
Why can the overlying skin look normal in the early stages of nec fasc?
Because it spreads deep along fascial planes
| Overlying skin progresses from pale red to purple with blister or bullae development
60
What does thin, foul-smelling gray drainage from would indicate?
A necrotizing fasciitis
61
What is the treatment for nec fasciitis?
Early debridement, high dose penicillin (broad spectrum if thought to be poly-organisms
62
What are the common presentations of C. Perfringens infections?
Myonecrosis and gas gangrene
63
Why is necrotic tissue a perfect environment for C. Perfringens?
Necrotic tissue decreases oxidation-redux potential
64
What toxin does C. Perfringens have?
Alpha toxin
65
What does gram stain show in wound with C. Perfringens?
GPRs without WBCs
66
What is seen on physical exam in a patient with C. Perfringens infection?
Pain out of proportion to exam
67
What is the treatment for C. Perfringens infected wounds?
Early debridement, high-dose penicillin
68
What is Fournier’s gangrene?
Severe infection in perineal and scrotal region
69
What are the risk factors for developing Fournier’s gangrene?
Diabetes and immunocompromised state
70
What causes Fournier’s gangrene?
Mixed organisms
71
What is the treatment of Fournier’s gangrene?
Early debridement and try to preserve testicles if possible
| Antibiotics
72
When is fungal coverage warranted?
Positive blood cultures, 2 sites other than blood, 1 site with severe symptoms, endophthalmitis, or patients on prolonged bacterial antibiotics with failure to improve
73
What symptoms are most common with actinomyces (not a true fungus)?
Pulmonary symptoms
74
What does Actinomyces usually cause?
Pulmonary symptoms and tortuous abscesses in cervical, thoracic, and abdominal areas
75
Histologic characteristic of Actinomyces?
Yellow sulfur granules on Gram stain
76
What is the treatment for Actinomyces?
Drainage and penicillin G
77
What are the most common symptoms of Nocardia (not a true fungus)?
Pulmonary and CNS symptoms
78
What is the treatment for Nocardia?
Drainage and sulfonamides (Bactrim)
79
What organism is the MCC of fungemia?
Candida
80
Candida is a common inhabitant of what part of the body?
Respiratory tract
81
What is the treatment of Candida?
Fluconazole or anidulafungin for severe infections
82
What is the treatment for Candiduria?
Remove urinary catheter only, no anti-fungal is necessary
83
What is the treatment for Aspergillosis?
Voriconazole for severe infections
84
What are the most common symptoms of Histoplasmosis?
Pulmonary
85
Where is Histoplasmosis usually found?
Mississippi and Ohio River Valleys
86
What is the treatment of histoplasmosis?
Liposomal amphotericin for severe infections
87
What symptoms are most common with Cryptococcus?
CNS symptoms
88
In what patients is Cryptococcus usually found?
AIDS patients
89
What is the treatment of Cryptococcus?
Liposomal amphotericin
90
What type of symptoms are often seen with Coccidioidomycosis?
Pulmonary symptoms
91
What region is Coccidioidomycosis usually found?
Southwest
92
What is the treatment of Coccidioidomycosis?
Liposomal amphotericin
93
What are the symptoms of spontaneous bacterial peritonitis (SBP)?
Mental status changes, fever, abdominal pain in cirrhotic patient
94
What is a risk factor for developing SBP?
Low protein (<1g/dL) in peritoneal fluid
95
What are the 3 most common causes of SBP?
50% E. coli
20% Streptococcus
10% Klebsiella
96
What causes SBP?
Secondary to decreased host defenses (intrahepatic shunting, impaired bactericides activity in ascites), NOT transmucosal migration
97
How do you diagnosis SBP?
Peritoneal tap that shows PMNs >250 or positive cultures
| Fluid cultures are often negative
98
What is the treatment of SBP?
Ceftriaxone or other 3rd-generation cephalosporin
99
When should you worry about other intra-abdominal causes when treating someone with suspected SBP?
If not getting better on antibiotics or if cultures are polymicrobial
100
What antibiotic is used for prophylaxis for SBP?
Weekly fluoroquinolones (norfloxacin)
101
When is SBP prophylaxis indicated?
After an episode of SBP
102
Can a liver transplant be performed with active SBP?
NO
103
What is secondary bacterial peritonitis?
Comes from abdominal source
104
What does secondary bacterial peritonitis imply?
That there is a perforated viscous
105
What are the common bacterial causes of secondary bacterial peritonitis?
Polymicrobial— B. Fragilis, E. Coli, Enterococcus
106
What is the treatment for secondary bacterial peritonitis?
Usually laparotomy to find source
107
What type of virus is HIV?
RNA virus with reverse transcriptase
108
What are the exposure risks for developing HIV?
HIV blood transfusion — 70%
Infant from positive mother — 30%
Needle stick from positive patient — 0.3%
Mucous membrane exposure — 0.1%
109
How long does it usually take for seroconversion of HIV Abs?
6-12 weeks
110
What drugs are used to help decrease seroconversion of HIV after exposure?
AZT (zidovudine, reverse transcriptase inhibitor) and ritonavir (protease inhibitor)
111
What is the most common indication for laparotomy in HIV patients?
Opportunistic infections
112
What is the MC infection in HIV patients?
CMV
113
What is the second MC reason for laparotomy in HIV patients?
Neoplastic disease
114
What it’s he most common neoplastic disease that requires laparotomy in HIV patients?
Lymphoma
115
What is the MC intestinal manifestation of AIDS?
CMV colitis— can present with pain, bleeding, or perforation
116
What is the MC neoplasm in AIDS patients?
Kaposi’s sarcoma —rarely needs surgery
117
What is the MC and second MC site of lymphoma in HIV patients?
1. Stomach
| 2. Rectum
118
What type of lymphoma is MC seen in HIV patients?
Non-Hodgkin’s (B cell)
119
What is the treatment of lymphoma in HIV patients?
Chemotherapy. May need surgery with significant bleeding or perforation
120
What type of GI bleed is more common in HIV patients? Lower or upper
Lower
121
What is the MCC of upper GI bleeds in HIV patients?
Kaposi’s sarcoma and lymphoma
122
What are the MCC of lower GI bleeds in HIV patients?
CMV, bacterial, HSV
123
What is the normal CD4 count?
800-1200
124
At what CD4 count wil; HIV be symptomatic?
300-400
125
At what CD4 count will opportunistic infections occur?
<200
126
What is the possibility of transmitting hepatitis C through blood transfusion?
0.0001%/unit
127
What percentage of the population is infected by hepatitis C?
1-2%
128
In what % of patients with hepatitis C does chronic infection occur?
60%
129
In what % of patients with hepatitis C dose cirrhosis occur?
15%
130
In what % of patients with hepatitis C does hepatocellular carcinoma occur?
1-5%
131
What is the most common indication for liver transplant?
Hepatitis C
132
What drugs are used to cure hepatitis C?
Sovaldi (sofosbuvir) with ribavirin
133
Is fulminant hepatic failure common in patients with hepatitis C?
NO
134
How is CMV transmitted?
Via leukocytes
135
What is the most common infection in transplant patients?
CMV
136
What is the MC manifestation of CMV?
Febrile mononucleosis (sore throat, adenopathy)
137
What is the most deadly form of CMV?
CMV pneumonitis
138
How do you diagnose CMV infection?
Biopsy and CMV serology
139
What would you see on the biopsy in someone infected with CMV?
Characteristic cellular inclusion bodies
140
What is the treatment for CMV?
Ganciclovir, CMV immune globulin (Cytogram)
141
In what cases is CMV immune globulin (Cytogram) given?
For severe infections or a CMV-negative patient receiving a CMV-positive organ
142
Where in the lungs is aspiration pneumonia MC seen?
Superior segment of the right lower lobe
143
What is the MC organism causing aspiration pneumonia? What other class of organism must you also treat against?
Strep pneumonia. Must also cover anaerobes
144
What is the highest sensitivity test for osteomyelitis?
MRI (avoid bone biopsy)
145
What is the treatment for Brown recluse spider bites?
Oral Dawson initially, avoid early surgery, but may need resection of area and skin graft for large ulcers later
146
What are the most common causes of diabetic foot infections?
Usually polymicrobial. Staph, strep, GNRs, and anaerobes
147
What is the treatment for diabetic foot infections?
Broad-spectrum antibiotics (Unasyn, Zosyn)
148
What are the MC causes of acute septic arthritis?
Gonococcus, staph, H. Influenzae, strep
149
What is the treatment for acute septic arthritis?
Drainage, 3rd generation cephalosporin and vancomycin until results of cultures
150
What organism is only found in human bites and cause permanent joint injury?
Eikenella
151
What organism is found in cat and dog bites?
Pasteurella multocida
152
What is the antibiotic of choice for cat/dog/human bites?
Augmentin
153
What is the MC infection resulting from cat/dog/human bites?
Strep pyogenes
154
What are the 2 MC organisms to causes impetigo, erysipelas, cellulitis, and folliculitis?
Staph (MC) and strep
155
What is a furuncle and what organisms usually cause it?
A boil. S. Epidermidis or S. Aureus
156
What is the treatment of a furuncle?
Drainage +/- antibiotics
157
What is a carbuncle?
A multiloculated furuncle
158
What are the symptoms of a peritoneal dialysis catheter infection?
Cloudy fluid, abdominal pain, fever, usually mono bacterial
159
What are the MC organisms to cause peritoneal dialysis catheter infections?
S. Epidermidis (MC), S. Aureus, and pseudomonas
160
What is the treatment for peritoneal dialysis catheter infections?
Intraperitoneal vancomycin and gentamicin (IV not as effective) and increased dwell time and intraperitoneal heparin
161
When should you remove the catheter in a patient with a peritoneal dialysis catheter infection?
For peritonitis that lasts 4-5 days
162
Peritoneal dialysis catheter should be removed if infected with what organisms?
Fungal, tuberculosis, and pseudomonas infections
163
What are the risk factors for developing sinusitis?
Nasoenteric tubes, intubation, patients with severe facial fractures
164
What organisms usually cause sinusitis?
Polymicrobial
165
What would the CT head of a patient with sinusitis show?
Air-fluid levels in the sinus
166
What is the treatment of sinusitis?
Broad-spectrum antibiotics
| It is rare to have to tap sinus percutaneously for systemic illness
167
What is the best prevention strategy to prevent nosocomial infections?
Hand washing
168
What patients have the highest risk of developing a nosocomial infection?
Burn patients
169
What are the prevention strategies used to prevent surgical site infections?
- Use clippers preoperativey instead of razors
- Keep glucose 80-120
- Keep PO2 elevated (give 100% oxygen)
- Keep patient warm (keep OR 70F, and use Bair Hugger (warm air conduction)
- Chlorhexidine prep with iodine-impregnated drapes
