Pathology of infection (sepsis)

Question 1

What is sepsis?

Answer 1

Life threatening organ dysfunction secondary to infection

Question 2

What is required for sepsis to be diagnosed clinically?

Answer 2

Infection suspected and SOFA score 2+

Question 3

What is a qSOFA based on?

Answer 3

SBP<100
Resp rate>22
Altered mentation
Presence of infection

Question 4

What is septic shock caused by?

Answer 4

Inotropes-
MAP>65
Lactate>2

Question 5

What is the mortality of sepsis compared with septic shock?

Answer 5

Sepsis- 10%

Septic shock- 40%

Question 6

What infections are caused by Group A strep?

Answer 6

Throat carriage
Sore throat
Tonsilitis
Invasive:
Cellulitis
Necrotising fasciitis
Pueperal sepsis
Septicaemia
Pneumonia

Question 7

Who does invasive group A strep disease affect?

Answer 7

M and F of all ages- rapid onset

Question 8

What is the mortality of invasive group A strep disease?

Answer 8

20-40%

Question 9

How do you treat invasive group A strep infection?

Answer 9

Supportive (ITU), debridement, antibiotics, antitoxin antibiotics, IVIgG

Question 10

How do streptococci get from throat to tissues?

Answer 10

Trauma- 1/4 patients e.g. surgery and injecting drugs
Skin lesion- 1/4 patients e.g. eczema and chicken pox
Intact skin, blunt trauma- 1/4 patients
No recalled skin lesion or trauma- 1/4 patients

Question 11

What causes the paucity of the host neutrophil response to strep infection?

Answer 11

S pyogenes cleaves interleukin-8 (and all neutrophil chemokines) using enzymes (SpyCEP) in order to restrict neutrophil recruitment. SpyCEP is normally repressed by a bacterial regulatory gene. This strain had a regulatory gene mutation

Question 12

What is the main reservoir for group A strep?

Answer 12

Children

Question 13

What factors affect if the infection is active?

Answer 13

Bacterial factors and host factors- seasonal variation- scarlet fever surges etc (spring)