Pathophysiology and Treatment of Sepsis Flashcards
What are the Sepsis Six?
A list of guidelines set out in case of a sepsis emergency:
- Administer high flow oxygen
- Take blood cultures
- Give broad spectrum antibiotics
- Give intravenous fluid challenges
- Measure serum lactate and haemoglobin
- Measure accurate hourly urine output
BUFALO
What does septicaemia mean?
Presence of pathogen in the blood
What does SIRS stand for?
Systemic Inflammatory Response Syndrome
Define sepsis.
Suspected or proven infection plus systemic inflammatory response (e.g. fever, tachycardia, tachypnea,WBC, altered mental state, hyperglycaemia in absence of diabetes)
What is severe sepsis?
Sepsis plus organ dysfunction (e.g. hypotension, hypoxaemia, oliguria, metabolic acidosis, thrombocytopoenia or obtundation (decreased sensitivity)
What is septic shock?
Severe sepsis plus hypotension, despite fluid resuscitation
SIRS is defined by the presence of two or more factors. List the 5 factors that make up the potentials.
- Respiratory rate >20/min
- Heart rate >90/min
- WBC>12x109/Lor<4x109/L
- Temperature >38oC or <36oC
- PaCO2 <4.3 kPa or ventilated
What physiological changes do SIRS produce?
Widespread endothelial damage with vasodilation Arterio-venous shunting Microvascular occlusion Capillary leak Tissue oedema
What two conditions are indicators of severe infection?
Hypothermia Septic neutropenia (low neutrophil blood count)
What are some of the clinical presentations (i.e. signs and symptoms) of SIRS?
Warm peripheries
Bounding pulses and features of high cardiac output
Peripheral vasodilation leading to diastolic BP
Decreased afterload, therefore stroke volume and systolic BP is maintained
Large difference between DBP and SBP e.g. 115/42mmHg
What clinical presentations can arise as sepsis develops and advances?
Systolic BP decreases and the peripheries become cool due to hypovolaemia associated with capillary leak
List some of the risk factors associated with sepsis.
Immunosuppression Asplenic patients Diabetics Pregnancy Cancer patients Prosthetic devices Mechanical ventilation Severe wounds / burns Post-surgery Extremes of age
Sepsis has a very wide range of causes; to list a few:
– RT infections – UT infections – Meningitis – GI infections – Pelvic and GU infections – Line infections – Skin and soft tissue infections
What type of bacilli are most likely to cause sepsis?
Gram negative cocci
What are some examples of host barrier integrity breach?
Skin Mucous membranes Catheters Wounds Burns Thorn pricks Insect bites Epithelial cell damage
What are some of the factors that can affect signs and symptoms of sepsis?
- Virulence of pathogen
- Bioburden
- Portal of entry
- Host susceptibility
- Temporal evolution (when the signs/symptoms manifest themselves)
What does the AVPU Scale assess?
Alert
Voice
Pain
Unresponsiveness
What are care bundles and what is their function?
Structured way of improving processes of care
Straightforward set of practices
When performed collectively, reliably and continuously, improve patient outcomes
Give 5 examples of care bundles.
– Infection control – Peripheral vascular catheters (PVCs) – Stroke – Ventilator-associated pneumonia (VAP) reduction – Sepsis
What is the difference between exotoxin and endotoxin?
Exotoxin is a toxic substance secreted by the bacterium
Endotoxin is part of the bacterium that is toxic, e.g. LPS in the bacterium cell wall
Name an example of a bacterium that contains an endotoxin and list some additional symptoms that can present.
Streptococcus pyogenes
Cellulitis
Toxic shock
Hypotension
Altered mental state
What does CFU stand for?
Colony forming unit
What is the bioburden?
Number of bacteria living on a surface that has not been sterilised
Name a type of bacterium that can make up a large proportion of the bioburden contributing to sepsis.
Salmonella typhimurium
With 10^3 CFUs of Salmonella typhimurium, what symptoms can arise?
Gurgling stomach
Loose stools
With 10^5 CFUs of Salmonella typhimurium, what symptoms can arise?
Haemorrhagic colitis
Fever
Abdominal pain
If the bacterium Klebsiella pneumoniae enters renally, what can be some associated symptoms?
Tachycardia
Fever
If Klebsiella pneumoniae enters via the chest, what can be some associated symptoms?
Tachycardia
Fever
Hypotension
If Streptococcus pneumoniae infection occurs in a fit adult, what are likely to be the only symptoms?
Pneumonia
Fever
If Streptococcus pneumoniae infection occurs in an elderly person, what additional symptoms are likely to arise?
Fever Pneumonia Physical unsteadiness Confusion Altered mental state
In a case of Neisseria meningitidis infection, what are some early symptoms?
Fever Malaise Headache Myalgia Arthralgia
In a case of Neisseria meningitidis infection, what are some later symptoms?
Septic shock
Altered mental state
Hypotension
What is the first line of defence against pathogenic insult?
Innate Immune Response
What does TLR-4 recognise?
LPS
List 5 immune molecules/cells/receptors that are actively involved in the innate immune response.
Complement cascade Mannose-binding lectin (MBL) Phagocytes Toll-like receptors (TLRs) Nucleotide-binding oligomerisation domain receptors (NLRs)
What are TLRs?
Pattern recognising receptors recognising certain elements of pathogens
Production of inflammatory markers may be initiated. Name 3 types of inflammatory marker.
– Interleukins (ILs)
– Tumour necrosis factor alpha (TNFα)
– Reactive oxygen species (ROS)
What are the 3 major steps in immune action?
Access
Recognition
Response
What normally compromises the initial response?
Inflammation
List some causiative mechanisms and their subsequent responses.
Increase in glucose Increase in temperature Low O2 levels and low blood flow Decrease in fibrinolysis Tries to vasoconstrict… But NO and endotoxins try to vasodilate… Endothelium starts to break down
Increased (but not uncontrolled clotting of blood)
What effects do TNF(alpha) and Interleukin-1 (IL-1) have on the body?
Fever Hypotension Increased HR Corticosteroid and ACTH (adrenocorticotrophic hormone) release Release of neutrophils
What effects do TNF(alpha) and Interleukin-1 (IL-1) have on the CVS specifically?
- Generalised vasodilation (NO.)
- Increased vascular permeability (activated leukocytes) (albumin moves out into interstitium, thus taking fluid with it and decreasing blood volume))
- Intravascular fluid loss
- Myocardial depression (tissue hypoxia)
- Circulatory shock
