Immunity, Anaphylaxis, Allergy Primer Flashcards
Name several factors that can affect the body’s immune response.
- CNS integrity
- General physical condition
- Emotional status
- Medications
- Dietary factors
- Illness, trauma, or surgery
“Immunity” is the responsiveness to…
The invasion of foreign substances
What are the 3 functions of our immune system?
- Defence: protection against micro-organisms
- Homeostasis: damaged cellular substances digested and removed
- Surveillance: mutations recognized and removed
What are the 2 “types” of immunity?
- Innate: born with
- Acquired: acquired after birth
What are the 2 types of acquired immunity?
- Active:
- Immunity developed due to exposure to disease/inoculation
- Passive:
- Acquired by receiving antibodies rather than synthesizing them
- Can xfer across the placenta
- Short lived due to lack of memory for the antigen
Describe the “innate” immune system.
- Present at birth
- First line of defense that responds w/in minutes without prior exposure as it is not cell specific
- Neutrophils and monocytes are the primary WBCs for this response
Describe the “acquired” immune system.
- Invasion of foreign substances and subsequent development of antibodies and sensitized lymphocytes
- With each reinvasion the body responds more rapidly
Humoral response relates to the body ____ response, with antibodies produced by ____ cells.
Fluid, plasma
In regards to a humoral response, when an individual is exposed to an antigen for a second time the response is ___ and lasts _____.
Faster (1 to 3 days), longer
A main product of secondary humoral response is ___ rather than ___.
IgG, IgM
Memory cells account for more rapid production of___.
IgG
Cell-mediated immune responses are initiated through…
Specific antigen recognition by T cells
What are three cell types involved in the cell-mediated immunity response?
- T lymphocytes
- Macrophages
- Natural Killer cells
Cell mediated responses are particularly important for immunity against pathogens _____ the cells including…
- Inside
- viruses and some bacteria, fungal infections, rejection of transplanted tissues, contact hypersensitivity, tumor immunity
What are some effects of ageing on the immune system?
- Greater susceptibility to pathogens (ex. influenza pneumonia)
- Higher incidence of malignancies
- Bone marrow relatively unaffected
- Immunoglobulin levels decrease
- Decreased numbers of T cells
- Ability to develop new antibodies decreased
- Delayed hypersensitivity reaction
Decreased immunoglobulin levels lead to a…
Suppressed immune response.
An antigen is…
A substance that elicits an immune response
What are the key factors to remember regarding Tumor Necrosis Factor (TNF)?
- Activates macrophages and granulocytes
- Promotes the immune and inflammatory responses
- Kills tumor cells
- Responsible for extensive weight loss
- Associated with chronic inflammation and cancer
What are some signs of recognizing anaphylactic shock?
Edema and itching at the site of exposure, possible angioedema, followed by shock symptoms: rapid weak pulse, hypotension, dilated pupils, dyspnea, bronchial edema.
What happens if anaphylactic shock isn’t treated immediately?
If not treated immediately will lead to death.
What are the cardinal principles of treating anaphylaxis?
- Recognition of the signs and symptoms
- Maintenance of patient’s airway (high flow O2)
- Prevention of spread by using a tourniquet (remove stinger if present/applicable)
- Administration of the appropriate drugs (establish IV access)
- Treatment of shock (fluids and ongoing monitoring)
What is the drug regimen for anaphylaxis?
- Epinephrine (1:1000) every 5-15 mins until desired result achieved
- Nebulized albuterol (Proventil)
- Diphenhydramine (Benadryl) IM or IV
- Corticosteroids (methylprednisolone, hydrocortisone)
Why would the administration of epinephrine for anaphylaxis be of concern for someone on beta blockers?
Beta blockers attenuate the response to epinephrine and the combo may cause the pt to develop bradycardia and hypotension
True or False
If a pt is on Beta blockers, you should withhold epinephrine in treating anaphylaxis.
False. Give it, but monitor for bradycardia and hypotension
A pt on beta blockers receives epinephrine and develops bradycardia, what may be given and how?
- Atropine
- 0.5mg via IM or SubQ every 10 mins
What drug may be used to treat hypotension for a pt who has rec’d epinephrine and how would it be administered?
- Glucagon
- 1mg IV bolus followed by 1-5mg/hr infusion
True or False
The initial exposure triggers the response and mass release of chemical mediators seen in the overreaction or hypersensitivity of anaphylactic shock.
- FALSE!
- Overreaction or hypersensitivity seen in anaphylactic shock is NOT due to the first exposure but the SECOND causes a trigger response and mass release of chemical mediators
Name the four different types of immune reactions.
I: Atopic or Contact Dermatitis
II: Cytotoxic and Cytolytic reactions
III: Immune complex reactions
IV: Hypersensitivity reactions
What does “atopic” mean?
A form of allergy in which a hypersensitivity reaction such as dermatitis or asthma may occur in a part of the body not in contact with the allergen
What are some of the conditions that can result of type I reactions?
- Allergic rhinitis
- Atopic dermatitis
- Urticaria (hives)
- Angioedema
Atopic reactions can happen as a response to _____ conditions.
Environmental
What are the target areas for a type I immune reaction?
- conjunctiva of eyes
- mucosa of upper respiratory tract
What are the s/s of a type I immune reaction?
- Sneezing
- Nasal discharge
- Itching of the throat
- Eyes watering
Allergic rhinitis is triggered by a sensitivity to:
- Grasses
- Pollens
- Dust
- Animal dander
- Mold
What is atopic dermatitis?
- Atopic dermatitis (eczema) is a condition that makes your skin red and itchy.
- It’s common in children but can occur at any age.
- Atopic dermatitis is long lasting (chronic) and tends to flare periodically.
- It may be accompanied by asthma or hay fever.
What is Urticaria (hives)
- Transient wheals
- Red, itchy welts that result from a skin reaction.
- The welts vary in size and appear and fade repeatedly as the reaction runs its course
What is Angioedema?
- An abrupt and short-lived swelling of the skin and mucous membranes.
- All parts of the body may be affected but swelling most often occurs around the eyes and lips.
Define Type II Cytotoxic/Cytolytic reactions.
Direct binding of IgG or IgM antibodies to an antigen on the cell surface that target the cell for destruction
An incompatible blood transfusion results in what type of immune reaction?
Type II
Explain the patho of an incompatible blood transfusion.
- Antigens coat foreign erythyrocytes
- Clumping occurs and causes blockage of small blood vessels resulting in a depletion of clotting factors
- Phagocytosis of agglutinated (clumped) cells
- Release of hemoglobin into the urine and plasma
- Cytotoxic reaction causes vasospasm in the kidney resulting in blockage of kidney tubules
Type III immune reactions are associated with _____ disorders.
Autoimmune
What is the patho of a Type III immune response?
- An abnormal immune response is mediated by the formation of antigen-antibody aggregates called “immune complexes.”
- They can precipitate in various tissues such as skin, joints, vessels, or glomeruli, and trigger the classical complement pathway.
What are some examples of conditions that cause a Type III immune response?
- SLE
- RA
- Acute glomerular nephritis
Type IV immune reaction is a _____ response.
Cell mediated
How does a type IV immune reaction develop?
- Sensitized T lymphocytes attack antigens or release cytokines which attract macrophages into the area
- It is a type of hypersensitivity reaction that takes several days to develop.
Contact dermatitis is a example of what type of immune reaction?
Type IV
What are some ways that hypersensitive allergic reactions may be mediated?
- Reducing exposure
- Desensitizing (immunotherapy)
- Chronic allergies: lifestyle changes
- Allergen recognition and control
An example of a sympathomimetic decongestant drug is…
Adrenaline
How/why are antipuritics used?
topically applied protect skin and provide relief from itching (calamine lotion, coal, tar preparations)
What do anti-mast cell stabilizing drugs do?
Inhibit cytokine release thus immune reactions
When is immunotherapy used?
When the allergen cannot be avoided
A RAST test is used to determine…
sensitivity to certain food types, severe anaphylactic reactions
What type of blood test is used for dx of allergies?
CBC w/ diff
Eosinophil count is elevated with type __ sensitivity.
1
What type of skin tests may be used for allergy dx?
- Patch
- Scratch or prick
- Intradermal
If a person has a skin test done, the hypersensitive reaction will occur when?
w/in minutes
How long will the positive reaction to a scratch test last?
8-12hrs
With patch testing, the patch needs to be worn for ___ hours then the patient should come back for the site to be assessed.
48 – 72hrs
How is immunotherapy performed?
- Accurate record keeping to prevent an adverse reaction
- After administration anticipate adverse reactions (puritis urticarial, sneezing laryngeal edema)
- Administer away from the joint so a tourniquet can be applied in an emergency
- Rotate the site
- Ensure you don’t inject into the bloodstream
- Observe for any reaction
What is apheresis?
Separation of blood into its separate components followed by the removal of 1 or more of the separated components
What is Plasmapheresis?
- Aka: plasma exchange
- Removal of plasma containing components thought to cause disease and replacement with saline, fresh frozen plasma, or albumin
What are some side effects of plasmapheresis?
Hypotension and as the result of a vasovagal reaction citrate toxicity
Citrate is used as an _____ and may cause _____ manifesting as a headache dizziness or paresthesias.
Anticoagulant, hypocalcaemia
