Session 3

Question 1

What is sepsis?

Answer 1

A life threatening organ dysfunction due to a disregulated host response to infection

Question 2

What is septic shock?

Answer 2

Persistent hypotension requiring treatment to maintain blood pressure despite fluid resuscitation

Question 3

What urgent investigations are done with sepsis?

Answer 3

• fbc
• edta bottle for PCR
• blood sugar
• liver function test
• c reactive protein
• coagulation studies
• blood gases

Question 4

What tests can be done to confirm the diagnosis of sepsis?

Answer 4

• blood culture
• PCR of blood
• lumbar puncture if safe (do ct scan to make sure intercranial pressure is okay)

Question 5

What is bacteriaemia?

Answer 5

The prescence of bacteria in the blood

Question 6

What are the life threatening complications of sepsis?

Answer 6

• Irreversible hypotension
• respiratory failure
• renal failure
• raised intracranial pressure
• ischaemic necrosis of hands/feet

Question 7

What are the sepsis red flags?

Answer 7

• responds only to voice/pain or is unresponsive
• acute infused state
• low systolic blood pressure (less than or equal to 90mmHg)
• tachycardic
• respiratory rate more than or equal to 25 a minute
• non blanching rash
• no urine in 18 hrs
• recent chemotherapy

Question 8

What is the sepsis six bundle?

Answer 8

A group of interventions than when use together have a better outcome for the patient
Give 
- empiric intravenous antibiotics
- intravenous fluid resuscitation 
- oxygen to a target situation of 94%

Take

• blood cultures
• serum lactate
• urine output measurements

Question 9

What is the link between sepsis and coagulation?

Answer 9

• cytokines initiate production of thrombin = promote coagulation
• cytokines also inhibit fibriolysis (the breakdown of fibrin in blood clots)
• so, cascade leads to microvascular thrombosis and organ ischaemia, disfunction, organ failure and shock.

Question 10

What is infectivity?

Answer 10

The ability of a microbe to establish itself in the host

Question 11

What are the physical innate barriers to infection?

Answer 11

• skin
• mucous membranes: mouth, respiratory and GI tract, urinary tract
• bronchial cilia

Question 12

What are the innate physiological barriers to infection?

Answer 12

• diarrhoea e.g food poisoning
• vomiting e.g food poisoning, hepatitis, meningitis
• coughing e.g pneumonia
• sneezing e.g sinusitis

Question 13

What are the innate chemical barriers to infection?

Answer 13

• low pH e.g skin, stomach and vagina

- antimicrobials molecules e.g IgA, lysosomes, mucus, gastric acid etc.

Question 14

What are the innate biological barriers to infection?

Answer 14

• normal flora in strategic locations
• therefore they compete with pathogens for attachment sites and resources, as well as producing anti microbial chemicals and synthesising vitamins

Question 15

What patients are at high risk of infection?

Answer 15

• asplenic patients
• patients with damaged or prosthetic valves
• patients with previous infective endocarditis

Question 16

What do macrophages produce?

Answer 16

Cytokines and chemokines

Question 17

What white cell increases during infection?

Answer 17

Neutrophils. Are recruited by chemokines to the site of infection

Question 18

How are pathogens recognised by phagocytes?

Answer 18

• pathogen associated molecular patterns (PAMPS)

- pathogen recognition receptors (PRRs) on phagocyte

Question 19

What are the two activating pathways in the complement system?

Answer 19

Alternative pathway
- initiated by cell surfaces microbial constituents

MBL pathway
- initiated when MBL binds to mannose containing residues of proteins found on many microbes

Question 20

What are the most important serum proteins in the complement pathway and what do they do?

Answer 20

C1-c9 most important

• c3a and c5a = recruit phagocytes
• c3b-c4b = opsonisation
• c5- c9 = killing of pathogens with a membrane attack complex