Module 4 - Infection and Immunity Flashcards
What are the 3 lines of defense?
- Anatomic barriers
- Inflammatory response
- Immune response
What is the main anatomical barrier and how is it maintained?
Intact skin - usually lower than 37 degrees, around pH 3-5, normal flora, and some fatty acids to prevent bacterial growth and defend against invading pathogens
How is urine an anatomical barrier?
Our constant production of urine helps to flush out toxins (filtered out by the kidneys and excreted during voiding)
Which anatomical barriers are found in the respiratory tract? How do they act as barriers?
Cilia and circulating macrophages. Cilia can sweep pathogens out of the respiratory tract and macrophages can trap and destroy pathogens before they get into the lungs
What is the main anatomical barrier in the GI tract?
Gastric acid - very acidic, most pathogens and invading bacteria cannot survive
What is an acute inflammatory response?
The first response to cellular damage by an invading pathogen, irritant, or chronic health condition. This is usually triggered when our anatomical barriers fail
What is the purpose of inflammation?
To neutralize, or dilute toxins, remove necrotic tissue, and provide an environment for healing
Why is an inflammatory state potentially a bad thing?
An inflammatory state can cause further cellular and tissue damage, so if the body is stuck in a chronic inflammatory state, this can lead to more and more damage accumulating.
List 3 conditions that can cause inflammation:
- chronic illness (atherosclerosis, arthritis etc)
- physical trauma (cuts, lacerations,
- chemical trauma
- micro-orgaisms
What happens immediately after tissue or cellular damage?
Damaged tissues release mediators to start the inflammatory process
What is the first mediator in an inflammatory response? What is the role of this mediator?
Epinephrine - causes vasoconstriction to restrict the flow of blood and stop the spread of the toxin or reduce bleeding for a short time
Which effects are caused by chemotaxic and which are caused by vascular mediator responses?
Erythema (redness) is caused by both.
Edema and pain are caused by vascular mediators
Heat is caused by chemotaxic mediators.
What do the vascular mediators of the secondary response do?
Cause vasodilation and the capillary membranes to become leaky, both of which allow white blood cells to enter the damaged area
What do the chemotaxic mediators of the secondary response do?
Cause leukocytosis, basically attracting white blood cells to the region - this works in tandem with the vascular mediators
During the inflammatory response, what happens to the affected organ?
Loss of function
Can we diagnose inflammation based on only systemic signs/symptoms? Why or why not?
No - the systemic symptoms are applicable to a range of conditions
What are the systemic signs/symptoms of inflammation?
Malaise - a general feeling of unwell due to metabolic system increase
Nausea and anorexia - irritation of the stomach due to vascular mediators
Tachycardia + tachypnea - increased HR and RR due to epinephrine release
Fever - heat from chemical reactions, increased metabolic system activity to kill pathogens
What causes erythema?
Blood leaking out of capillaries
How does inflammation lead to edema (swelling)?
Fluid leaking from the blood vessels into the surrounding tissues
How is heat generated from inflammation?
Blood vessels near skin dilate, allowing increased blood flow from core
How can inflammation cause pain?
edema pushing up against skin and/or nerves, chemical mediators irritating nerves
How can inflammation cause loss of function?
Edema can limit mobility, damage cells, mediators can damage cells
What are the main localized signs + symptoms of inflammation?
Erythema, edema, pain, heat, loss of function
What is an easy way for us to detect inflammation in a patient during an assessment?
Look for heat and edema
What is typically the first test done for inflammation?
C Reactive Protein (CRP), released by the liver in response to inflammation
Are the tests for inflammation specific or non-specific?
CRP and ESR are non-specific
What are the usual levels for CRP?
3-5 mg/L
What are the usual levels for ESR?
Females: 0-20 mm/h
Males: 0-10 mm/h
How does an ESR work?
ESR = erythrocyte separation rate.
When inflammation is present, fibrinogen is released, and causes erythrocytes to stick together. This affects the speed at which these RBCs will separate from plasma, and the higher the number, the more inflammation is present.
Once we identify inflammation, what is our first goal of care? What are the subsequent goals of care?
Eliminate the trigger causing inflammation. The next goals are to reduce the edema and support the cellular function in the damaged area.
Which comes first for controlling inflammation, ice or heat? Why?
Ice first! We need to control the edema, so ice causes vasoconstriction. Heat comes after ice to enhance vasodilation and allow blood flow to the region, along with some muscle relief
What 3 classes of medications can we give for inflammation?
Anti-inflammatory, anti-histamine, and corticosteroids
What is the main type of anti-inflammatory medication, and what is one example?
NSAIDS –> ibuprofen
What is the mechanism of action for anti-inflammatory medications?
Inhibit prostaglandin synthesis via Cox1/2, which can irritate nerves, exacerbate pain, and cause leaky capillaries
What is one of the main risks with NSAIDs? How can we reduce this risk?
NSAIDs are acidic, so they leave the patient at risk for gastritis, or exacerbation of kidney issues. To reduce risk, give with food to neutralize acidity.