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Terms in this set (22)
What is the definition of sepsis?
Life threatening organ dysfunction due to a dis-regulated host response to infection which injures its own organs and tissues.
Change to baseline sequential organ failure assessment score.
Change to baseline sequential organ failure assessment score.
What is the definition of septic shock?
Is a subset of sepsis.
Profound underlying circulatory and cellular metabolic abnormality causing inadequate tissue perfusion.
Vasopressors are needed to treat severe hypotension and keep MAP above 65 mm/Hg. Lactate remains above 2 mmol/L despite fluid resuscitation.
Increased mortality rate.
Profound underlying circulatory and cellular metabolic abnormality causing inadequate tissue perfusion.
Vasopressors are needed to treat severe hypotension and keep MAP above 65 mm/Hg. Lactate remains above 2 mmol/L despite fluid resuscitation.
Increased mortality rate.
What are the risk factors for sepsis?
Increased age - above 65
Infancy
Immunosuppression e.g. HIV/AIDS, autoimmune disorders
Alcohol intake - increased organ failure risk.
Smoking - increased pneumonia risk
IV substance abuse
Recent traumatic injuries of invasive procedures.
Women who are pregnant, have given birth, miscarried or had a termination.
Infancy
Immunosuppression e.g. HIV/AIDS, autoimmune disorders
Alcohol intake - increased organ failure risk.
Smoking - increased pneumonia risk
IV substance abuse
Recent traumatic injuries of invasive procedures.
Women who are pregnant, have given birth, miscarried or had a termination.
What are some non-infectious causes of sepsis?
Pancreatitis
Tissue ischemia
Trauma/surgery
Burns
Thromboembolism
Vasculitis
Drug reactions
Autoimmune and neoplastic processes
Tissue ischemia
Trauma/surgery
Burns
Thromboembolism
Vasculitis
Drug reactions
Autoimmune and neoplastic processes
What are the main infectious causes of sepsis?
Pneumonia
Abdomen
Genitourinary
Also:
Endocarditis, meningitis, device-related, skin/soft tissue/bone/joint
Abdomen
Genitourinary
Also:
Endocarditis, meningitis, device-related, skin/soft tissue/bone/joint
What is SIRS?
A systemic immune system response (due to the innate immune system)
How does SIRS present?
Temp of 38 or above, or 36 and below
HR above 90 bpm
RR above 20 breaths a min
HR above 90 bpm
RR above 20 breaths a min
How can SIRS lead to sepsis and septic shock?
SIRS leads to a release of chemical mediators from the endothelium = histamines, prostaglandins, cytokines, chemokines.
This causes widespread vasodilation, capillary leakage, clotting cascade.
Intravascular dehydration, uncontrolled systemic clotting plus depletion of clotting factors (= bleeding) leads to reduced perfusion, multiple organ dysfunction = sepsis.
This causes widespread vasodilation, capillary leakage, clotting cascade.
Intravascular dehydration, uncontrolled systemic clotting plus depletion of clotting factors (= bleeding) leads to reduced perfusion, multiple organ dysfunction = sepsis.
How does SIRS occur?
Mast cells and macrophages released (innate IS) in response to tissue damage e.g. trauma. Mast cells release chemicals that attract WBCs e.g. neutrophils which phagocytose the pathogen.
Macrophages release cytokines to alert the other parts of the immune system in a widespread and uncontrolled positive feedback loop.
Macrophages release cytokines to alert the other parts of the immune system in a widespread and uncontrolled positive feedback loop.
What does massive cytokine release in SIRS cause?
Vasodilation as endothelium releases nitrous oxide in response to cytokines, reducing systemic vascular resistance. Leads to profound hypotension, affecting all body systems e.g. can cause AKI.
What are the effects of myocardial depression factor being released (inflammatory mediator)?
Reduces cardiac contractility so cannot respond adequately to fluid resus and generate a systolic pressure.
What does complement activation and histamine release cause in sepsis?
Global endothelial permeability leading to widespread oedema due to fluid and protein leakage.
Compounds hypotension due to loss of volume.
In the lungs it leads to alveolar barrier dysfunction as fluid floods the alveoli, reducing oxygen transfer.
= HYPOXIA. O2 cannot diffuse through the fluid, cells are bathed in oxygen deplete fluid.
Compounds hypotension due to loss of volume.
In the lungs it leads to alveolar barrier dysfunction as fluid floods the alveoli, reducing oxygen transfer.
= HYPOXIA. O2 cannot diffuse through the fluid, cells are bathed in oxygen deplete fluid.
What causes the global clotting cascade activation?
Attempts to repair the endothelium from the ROS release.
Tissue factor expression and fibrin deposition leads to microthrombi in the vasculature and organ failure due to diminished distal blood flow.
There is then widespread bleeding as clotting factor is used up.
Tissue factor expression and fibrin deposition leads to microthrombi in the vasculature and organ failure due to diminished distal blood flow.
There is then widespread bleeding as clotting factor is used up.
How does mitochondria and DNA become damaged in sepsis? What are the consequences?
Reactive oxygen species damage cell proteins, lipids, DNA and mitochondria so ATP production is reduced, cells hibernate as they cannot perform their functions.
Leads to AKI, myocardial and hepatic dysfunction, encephalopathy.
Leads to AKI, myocardial and hepatic dysfunction, encephalopathy.
What raises lactic acid (lactate) in sepsis?
With mitochondria not being able to perform their function due to ROS damage, and cells bathed in deoxygenated fluid, anaerobic cell respiration is used. There is a build up of lactic acid = metabolic acidosis.