Bacterial infections of the circulatory system

Question 1

Is bacteremia required for sepsis?

Answer 1

No

Question 2

Systemic inflammatory response syndrome (SIRS) is two or more of what conditions?

Answer 2

1. Fever or hypothermia 2. Tachypnea 3. Tachycardia 4. Abnormal WBC count (leukocytosis or leukopenia)

Question 3

What is severe sepsis?

Answer 3

Sepsis with one or more signs of organ failure

Question 4

What is septic shock?

Answer 4

Severe sepsis + hypotension

Question 5

What is refractory septic shock?

Answer 5

Septic shock that lasts for 1 hour and does not respond to fluid and pharmacologic treatment

Question 6

What is multiorgan failure?

Answer 6

Dysfunction of one or more organs + disseminated intravascular coagulation (DIC)

Question 7

What leads to DIC?

Answer 7

1. Early cytokines in systemic inflammation 2. IL-6 –> tissue factor –> DIC

Question 8

What initiates septic shock?

Answer 8

LPS, lipid A, TSST-1, polysaccharides of C. albicans, teichoic acid of staph, capsule of S. pneumo

Question 9

What is the pathophysiology of LPS-induced sepsis?

Answer 9

1. LPS binds to CD14 and TLR4 on phagocytes / APCs 2. Immune system activated 3. Inflammation / septic shock via TNFa, IL-1, IL-6

Question 10

What is the gram stain for staph aureus?

Answer 10

Gram positive

Question 11

What is the catalase test for staph aureus?

Answer 11

Catalase positive

Question 12

What is the coagulase test for staph aureus?

Answer 12

Coagulase positive

Question 13

How does strep TSS differ from staph TSS?

Answer 13

1. Strep TSS is usually accompanied by bacteremia 2. Strep TSS may also include necrotizing fasciitis

Question 14

What virulence factors are responsible for the clinical manifestations of strep TSS?

Answer 14

SpeA and SpeC

Question 15

During septic shock what percentage of patients will be positive for blood cultures?

Answer 15

40-70%

Question 16

What are the localized sites of infection for staph aureus and strep pyogenes?

Answer 16

Generalized erythroderma (looks like sunburn)

Question 17

What is the most common cause of acute endocarditis?

Answer 17

Staph aureus

Question 18

What is the most common cause of subacute endocarditis?

Answer 18

Viridans strep

Question 19

What are the clinical features of acute endocarditis?

Answer 19

1. High fever 2. Rapid damage to heart 3. Death within weeks

Question 20

What are the clinical features of subacute endocarditis?

Answer 20

1. Low fever 2. Slow damage to heart 3. Death over weeks to months 4. Skin lesions (splinter hemorrhages, Roth spots, Janeway lesions, Osler nodes)

Question 21

What are the viridans strep species associated with subacute endocarditis?

Answer 21

S. mitis and S. salivarius

Question 22

What is the hemolysis pattern for viridans strep?

Answer 22

Alpha or gamma

Question 23

What is the treatment for subacute bacterial endocarditis?

Answer 23

Penicillin + aminoglycoside (vancomycin for resistant strains)

Question 24

Viridans strep species are resistant to what agent?

Answer 24

Optochin

Question 25

What are the two main predisposing causes of infective endocarditis?

Answer 25

1. Susceptible cardiovascular substrate 2. Source of bacteremia

Question 26

What are the major criteria for bacterial endocarditis?

Answer 26

1. Positive blood culture with typical organism 2. Evidence of endocardial involvement

Question 27

What are the minor criteria for bacterial endocarditis?

Answer 27

1. Predisposition 2. Fever 3. Vascular phenomena 4. Immunologic phenomena 5. Microbiologic evidence

Question 28

What is the treatment for bacterial endocarditis?

Answer 28

Aggressive and prolonged antimicrobial therapy