EXAM #1: REVIEW

Question 1

What are the three major components of the innate immune system that defend against viral infection??

Answer 1

1) Type I IFN (alpha and beta IFN)
2) NK Cells
3) Macrophages

Question 2

What is the general mechanism by which NK cells kill virally infected cells?

Answer 2

Perforin and granzyme, which induce apoptosis

Question 3

What are the two ways that NK cells are induced to kill virally infected cells?

Answer 3

1) PAMPs and/or absence of MHC Class I
2) ADCC
- IgG is bound to virally infected cell
- CD16 of NK cells binds Fc portion of antibody

*Perforin and granzyme are released, triggering apoptosis

Question 4

What cytokines/ cellular product mediate the anti-viral effects of macrophages?

Answer 4

1) TNFa

2) NO

Question 5

List five functions of antibodies in an anti-viral response.

Answer 5

1) Prevention of viral binding to target cell
2) Opsonization
3) Complement activation
4) NK cell activation/ ADCC
5) Downregulation of viral gene expression

Question 6

What innate immunity cells predominate in the response against intracellular bacteria?

Answer 6

1) Marcophages

2) NK cells

Question 7

Outline how macrophages and NK cells are activated to produced an anti-bacterial (intracellular) response?

Answer 7

1) Macrphages activated to release IL-12
2) IL-12 activates NK cells
3) NK cells release IFN-gamma (Type II IFN)
4) IFN-gamma further activates macrophages
5) Macrophages release NO, which is a potent antibacterial measure

Question 8

What is the adaptive immune response to intracellular bacteria?

Answer 8

T-cells are activated to produce IFN-gamma, which activates macrophages

Question 9

List the major complications of acute otitis media.

Answer 9

1) TM rupture
2) Tympanosclerosis
3) Cholesteatoma
4) Mastoiditis
5) Lateral sinus thrombosis
6) Meningitis/ brain abscess

Question 10

How acute bacterial sinusitis treated?

Answer 10

1) Amoxicillin
2) Nasal decongestants
3) Mucolytics

Question 11

What are the major complications of acute bacterial sinusitis?

Answer 11

1) Meningitis
2) Cavernous sinus thrombosis
3) Boney invasion of the orbit

Question 12

What is the hemolysis pattern of S. pyogenes?

Answer 12

Beta

Question 13

What complement pathway is specifically inhibited by polysaccharide capsules?

Answer 13

Alternative pathway

Question 14

How does S. pyogenes evade the immune system?

Answer 14

• Produces M protein

- M protein prevents complement activation

Question 15

How does S. pneumoniae evade the immune system?

Answer 15

C3 protease

Question 16

What is the major mechanism of immunity against spirochetes?

Answer 16

Adaptive immunity

Question 17

What is the major role of cell-mediated immunity (Th1) in spirochete infections?

Answer 17

Clearing the infection

*Vs. Th2 that prevents reinfection

Question 18

What cell type mediates the innate immune response against fungal infections?

Answer 18

Neutrophils

*Partly why neutropenic patients are so susceptible to C. albicans

Question 19

What is the major adaptive immune mechanism against fungal infections?

Answer 19

Cell mediated immunity (Th1)

Question 20

What is the major immune mechanism against Plasmodium? What stage of infection is being targeted?

Answer 20

Th1 vs. the intrahepatic stage

Question 21

List four ways that parasites evade the immune system.

Answer 21

1) Conceal in gut lumen
2) Coat with host proteins
3) Produce enzymes that cleave bound antibodies
4) Inhibition of complement activation*

Question 22

List the four major organisms that cause infectious diarrhea.

Answer 22

1) E. coli
2) Salmonella
3) Shigella
4) C. diff

Question 23

How is H. pylori treated?

Answer 23

1) PPI + amoxicillin

2) PPI + clarithromycin + tinidazole

Question 24

What is quadruple therapy for h. pylori?

Answer 24

1) Bismuth subsalicylate
2) TCN
3) Metronidazole
4) Omeprazole

Question 25

Why is duration of diarrhea an important historical feature to ask about?

Answer 25

Less than 2 weeks= infectious

More than 2 weeks= not infectious

Question 26

What are the two major non-inflammatory diarrheas?

Answer 26

1) V. cholerae

2) ETEC

Question 27

What is the empiric treatment for chlamydia?

Answer 27

1) Ceftriaxone

2) Azithromycin

Question 28

What are the non-infectious etiologies of a presentation similar to a CNS infection?

Answer 28

1) Neoplasia
2) Collagen vascular disorder
3) Medications

Question 29

What are the expected CSF findings in bacterial meningitis?

Answer 29

• WBC: 1,000 - 5,000 (highest)
• Protein: 100- 500
• Neutrophils*
• Glucose less than 40

Question 30

What are the expected CSF findings in tuberculous meningitis?

Answer 30

• WBC: 50-300
• Protein: 50-300
• Mononuclear
• Glucose less than 45

Question 31

What are the expected CSF findings in viral meningitis?

Answer 31

• WBC: 50 - 1,000
• Protein: less than 200
• Mononuclear
• Glucose greater than 45

Question 32

What are the expected CSF findings in cryptococcal meningitis?

Answer 32

• WBC: 20 - 500
• Protein: greater than 45
• Mononuclear
• Glucose less than 40

*Also, high opening pressure

Question 33

If a CSF sample shows neutrophils, what is the etiology?

Answer 33

Bacterial

Question 34

If a CSF sample has a glucose higher than 45, what is the etiology?

Answer 34

Viral

Question 35

What are the two most common causes of viral meningitis?

Answer 35

1) Enterovirus

2) Herpes

Question 36

What three pathogens are associated with subacute/ chronic meningitis?

Answer 36

1) MTB
2) T. pallidum (syphillis)
3) B. burgdorferi (lyme)

Question 37

In a patient that has undergone neurosurgery, what bacterial pathogens are you concerned about causing meningitis?

Answer 37

1) Coagulase negative staphylococci

2) P. aeruginosa

Question 38

What drug is used to cover coagulase negative staphylococci?

Answer 38

Vancomycin

Question 39

What drug is used to cover P. aeruginosa?

Answer 39

4th generation cephalosporin e.g. Ceftazidime

Question 40

What is the appropriate initial therapy for cryptococcal meningitis?

Answer 40

1) Amphotericin B or fluconazole

2) Measures to reduce ICP

Question 41

What is a “fever” in a neutropenic patient?

Answer 41

1) Core temp greater than 38.0 or 100.4 F for an hour

2) Oral temp greater than 38.3 C/ 101.0 F

Question 42

In a child between 3 and 36 months, what what lead you to suspect occult bactermia as a source of fever?

Answer 42

1) WBC count greater than 15K

2) Temp greater than 39 C

Question 43

When are parenteral antibiotics indicated in a 3-36 month old with a fever without a source?

Answer 43

1) Ill appearing/ toxic appearance
2) Unstable
3) Abnormal lab findings
4) Unimmunized child

Question 44

If you are going to start parenteral antibiotics indicated in a 3-36 month old with a fever without a source, what antibiotic should you use? What organisms are you targeting?

Answer 44

Ceftriaxone to target:

• S. pneumoniae
• S. aureus
• N. meningitidis
• H. influenza

Question 45

What are the two most common causes of a “classic” fever of unknown origin in an adult?

Answer 45

Infection vs. malignancy

Question 46

What criteria define severe sepsis?

Answer 46

1) Hypotension– SBP less than 90 mmHg or MAP less than 70 mmHg
2) Tissue hypoperfusion–elevated lactate
3) Urine Output less than 0.5mL/kg/hr
4) Acute Lung Injury– PaO2/FiO2 less than 250
5) Bilirubin greater than 4.0
6) Creatinine greater than 2.0
7) Platelets less than 100,000

Question 47

What is the sequelae of pathologic events that occurs in sepsis?

Answer 47

1) Distributive shock
2) Myocardial depression
3) Bone marrow suppression
4) Activation of the clotting cascade
5) Organ dysfunction