Infectious disease emergency Flashcards
What is the definition of sepsis?
Sepsis is clinical evidence of infection together with 2 or more of the following quick Sequential [Sepsis-related] Organ Failure Assessment score (qSOFA) criteria: altered mentation (Glasgow Coma Scale <15), respiratory rate ≥22/min, and systolic BP ≤100 mm Hg.
What are the components of the quick Sequential [Sepsis-related] Organ Failure Assessment score (qSOFA)?
The qSOFA score includes:
1. Altered mentation (Glasgow Coma Scale <15)
2. Respiratory rate ≥22/min
3. Systolic BP ≤100 mm Hg.
How is septic shock defined?
Septic shock is sepsis with hypotension (systolic BP <90 mm Hg or a greater than 40 mm Hg fall in systolic BP) persisting despite adequate fluid resuscitation.
Effect of sepsis on the liver
Liver injury
- Impaired detoxification
-Impaired coagulation system
*Bleeding and DIC
- Altered metabolic response
- Hyper/ hypo glycemia
-Bilirubinemia
* Cholestasis
* Jaundice
Effect of sepsis on the intestines
Compromisation of intestinal barrier
- Release of bacteria into the system
* Peritonitis
Effect on sepsis on the lungs
Acute respiratory distress syndrome
-Leaky capillaries
*Compromised oxygen delivery
-Access route for secondary infection
Effect of sepsis on the thyroid
- Apoptosis
-Impaired T lymphopoiesis
Effect of sepsis on the lymph vessels
- Abcess formation
-Compromised local immune cell function
Effect of sepsis on the brain
Encephalopathy
- Coagulopathy
- Hypoxic ischemic brain damage
-Blood brain barrier dysfunction
-Decreased neurotransmitter release
* Delirium
Effect of sepsis on the heart
Heart failure
- Reduced oxygen in system causes heart to pump faster (>90 bpm)
- Abnormal O2 delivery
- Hypotension
-Defective contractibility
* Decreased cardiac output
Effect of sepsis on the spleen
Splenic pathology
- Splenomegaly
-Atrophy of lymphoid follicles
* Immune cell apoptosis
* Immunosupresion
Effect of sepsis on the kidneys
Renal failure
-Ischemia of tissue
Effect of sepsis on the bones
Bone marrow suppression
- Myelosupression/ lymphopaenia
- Apoptosis of WBVs
What is a proinflammatory response?
A proinflammatory response is the body’s immediate reaction to harmful stimuli, such as pathogens (bacteria, viruses), injury, or toxins. This response involves the activation of the immune system to fight off the perceived threat.
What is an antiinflammatory response?
An antiinflammatory response is the body’s mechanism to regulate and suppress the inflammatory process to prevent excessive tissue damage and to promote healing.
Why is the balance between proinflammatory and antiinflammatory responses important?
The balance between proinflammatory and antiinflammatory responses is crucial for maintaining health. An appropriate proinflammatory response is necessary to fight off infections and heal injuries, but it must be regulated by antiinflammatory mechanisms to prevent excessive tissue damage and chronic inflammation. Conversely, an excessive antiinflammatory response can lead to immunosuppression and increased vulnerability to infections. Maintaining this balance is essential for the body’s immune homeostasis and overall health
Proinflammatory response
- Host and pathogen interaction
- Pattern recognition receptors
-Signaling cascade - Leukocyte activation and infiltration
- Excessive cytokine release
- Complement activation
-Coagulation cascade activation
Anti-inflammatory response
- Impaired immune cell function
- Cell apoptosis and immune regulation
What do Pattern Recognition Receptors (PRRs) recognize?
PRRs recognize pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs).
What happens after PRRs recognize PAMPs and DAMPs?
A cascade of intracellular signaling events occurs, leading to cytokine synthesis
What results from excessive cytokine release?
An increase in circulating immune cells.
What role does the complement system play?
It marks pathogens for destruction.
What does the coagulation cascade produce?
Coagulation products.
How are macrophages affected in the antiinflammatory response?
Impaired phagocytosis.
What defects occur in neutrophils?
Maturation defects.
How are NK cells affected?
Defective cytotoxic function.
What happens to T, B, and dendritic cells during the antiinflammatory response?
Programmed cell death (apoptosis).
What leads to immunosuppression during the antiinflammatory response?
Expansion of regulatory T cells.
What does an excessive inflammatory response lead to?
Tissue damage.
What happens during the immunosuppressive state in sepsis?
Increased vulnerability to secondary infections.
What initiates the coagulation cascade in the process of increased coagulation?
Monocytes release tissue factor, which initiates the coagulation cascade.
How do neutrophils contribute to the formation of thrombi (clots)?
Neutrophils form neutrophil extracellular traps (NETs) with trapped platelets, contributing to the formation of thrombi.
What are the main factors reduced in decreased anticoagulation?
Reduction in tissue factor pathway inhibitor and antithrombin levels.
What happens to thrombomodulin (TM) and endothelial protein C receptor (EPCR) in decreased anticoagulation?
Trombomodulin (TM) and endothelial protein C receptor (EPCR) are decreased, leading to reduced activation of protein C.
How does decreased activated protein C affect fibrinolysis?
Decreased levels of activated protein C result in reduced fibrinolysis, enhanced by an increase in plasminogen activator inhibitor-1 (PAI-1).
What effect does the formation of thrombi in the microcirculation have on tissue perfusion?
Formation of thrombi in the microcirculation leads to tissue hypoperfusion.
How does tissue hypoperfusion affect tissue oxygenation?
Tissue hypoperfusion results in decreased tissue oxygenation, contributing to mitochondrial dysfunction and release of mitochondrial contents, further exacerbating the condition.
What role do endothelial cells and PAR1 play in the loss of barrier function?
Endothelial cells express PAR1 (protease-activated receptor 1), activated by thrombin and protein C.
What happens to VE-cadherin and tight junctions in the loss of barrier function?
Decreased VE-cadherin and tight junctions cause increased capillary leak and interstitial edema.
What are the consequences of increased capillary leak and interstitial edema?
This leads to cell shrinkage, cell death, and further loss of barrier function.
What systemic changes occur due to the loss of barrier function?
Vasodilation and decreased blood pressure occur, reducing red cell deformability