Session 3 - Acute Sepsis Flashcards
Define Sepsis
A life-threatening organ dysfunction due to a dysregulated host response to infection
What urgent investigation need to be taken if sepsis is suspected?
- Full Blood Count, U’s and E’s
- Blood Sugar
- Liver Function
- CRP
- Coagulation Studies
- Blood Gases
Give the sepsis six bundle
- Give high flow oxygen
- Take blood cultures
- Give IV antibiotics
- Give a fluid challenge
- Measure lactate
- Measure urine output
How does an infection trigger an inflammatory response?
When a macrophage phagocytoses a microbe, endotoxins are released which bind to the macrophage and cause it to release Cytokines such as TNF and IL-1
How does sepsis cause organ failure?
The uncontrolled release of cytokines initiates the production of thrombin and inhibits fibrinolysis. The coagulation leads to micro vascular thrombosis which can lead to organ ischaemia and failure.
What is the empiric choice of antibiotic to give to a septic patient?
Ceftriaxone
What are some of the life-threatening complications of sepsis?
- Irreversible Hypotension
- Resp failure
- Acute kidney injury
- Increased intracranial pressure
- Ischaemic necrosis of the digits
Describe Neisseria Meningitidis
- Likely diagnosis for sepsis
- spread by direct contact with resp secretions
- most people are harmlessly colonised, but in a few can be fatal
- G -ve diplococcus with a pilus which enhances attachment to mucous membranes
What two ways can be prevent Meningococcal disease?
Vaccination or Antibiotic Prophylaxis
Name some physical barriers to infection.
- Skin
- Mucous Membranes
- Bronchial cilia
Name some physiological barriers to infection
- Diarrhoea
- Vomiting
- Coughing
- Sneezing
Name some chemical barriers to infection
- low pH in many parts of body (skin, stomach, vagina)
- anti microbial molecules (IgA, Lysozyme)
What is our main biological barrier to infection and how does it prevent infection?
Normal Flora
Compete with pathogens for space and growth substances, produce anti microbial chemicals and synthesise vitamins
When can normal flora cause clinical problems?
- When they are displaced to a sterile location
- When displaced from their normal location
- When they overgrow and become pathogenic
- when normal fora is depleted by antibiotics
Name the main cellular components of the innate immune system
- Macrophages
- Monocytes
- Neutrophils
What two methods do phagosomes have of destroying their target?
Oxygen dependent - using ROS
Oxygen independent methods - using lysosomal enzymes
What does PAMP stand for and what are they?
Pathogen-associated-molecular-patterns
Various classes of microbe share structure groups which can be recognised by innate immune cells
What are some of the main purposes of the complement pathway?
- Opsonise pathogens
- induce inflammatory responses
- form the membrane attack complex
What does C3 convertase do?
It cleaves C3 to form C3a and C3b
What does C3a do?
It is a peptide mediator of inflammation
What does C3b do?
Main effector of the complement system
Acts as an opsonin and also binds C3 convertase to form C5 convertase
What does C5a do?
It is a potent inflammatory peptide
What does C5b do?
It leads to the formation of the Membrane Attack complex
What the most important cytokines in the body?
TNF, Il-1 and Il-6
