Sepsis: Infection as a mechanism of disease

Question 1

What is sepsis?

What infections commonly cause sepsis ?

Answer 1

Characterised by organ dysfunction due to an abnormal response to infection

GP: staphyloccous aureus, c dif, streptococcus pneumoniae
GN: Klebsiella, pseudomonas, e coli

Question 2

What are risk factors for sepsis?

Answer 2

Age
Chronic diseases e.g CVS disease + diabetes -> organ dysfunction
Delay in treatment and diagnosis

Question 3

Describe the pathophysiology of sepsis

What microvascular + macrovascular changes occur?

Answer 3

PRRS bind to PAMPS
Inflammatory response, pro inflammatory cytokines are released causing tissue damage and necrosis
DAMPS activate leukocytes

Microvascular: Endothelial cell dysfunction + complement activation

Macrovascular: Vasodilation + hypotension, tachycardia

• Vascular leakage, oedema, decreased blood volume so less perfusion and oxygenation of tissues

Question 4

What are some of the clinical presentation of sepsis

Answer 4

Cold extremities 
Tachycardia
Altered mental state, coma, delirium 
increased respiratory sounds 
elevated liver enzymes + lactate

Question 5

How is sepsis diagnosed?

Answer 5

Anyone with known infection + apparent organ dysfunction can be considered as having sepsis
OR
Organ dysfunction + abnormal mental state/vital signs

SOFA = 6 step assessment of body systems which grades each 1-4/ 2> equal = positive

qSOFA = quicker version
> 100 systolic BP
> 22 breaths per min
< 15 GCS

Question 6

What is septic shock?

What can 3 things indicate septic shock?

Answer 6

The most sick patients will develop septic shock

It is sepsis with severe increased mortality due to circulatory, cellular + metabolic changes

• vasopressors to maintain SBP > 65
• Serum lactate >2mmol/L
• Sepsis that is not responsive to normal treatment e.g IV fluids + antibiotics

Question 7

What is the sepsis 6 and what does it involve?

Answer 7

• Oxygen administration
• blood cultures: identify microorganism and guide anti microbial therapy
• Antibiotics
• IV fluids - stabilise BP + treat hypolovaemia
• Lactate monitoring
• Measure urine output: Decreased in septic patients

Question 8

How are SOFA + qSOFA used in clinical practice?

Answer 8

SOFA score equal or greater than 2 is indicative of sepsis

negative QSOFA (<2) then check SOFA

Question 9

Why does lactate increase in sepsis/septic shock?

Answer 9

Hypo perfusion of organs + less oxygenation

Increased glycolysis + anaerobic respiration