Hypersensitivity Rxns Lecture Powerpoint Flashcards

8/26/19

1
Q

List the antibody mediated hypersensitivity reactions

A

Immediate
Cytotoxic
Immune complex

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2
Q

Name the antigen specific effector T cell mediated hypersensitivity reaction

A

Delayed

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3
Q

Type I hypersensitivity uses what kind of Ig molecule? When is this molecule created?

A

IgE, made the first time they are exposed to the antigen (called sensitization, could have occurred due to exposure to a cross reactive compound)

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4
Q

Timeframe of type I hypersensitivity

A

IV response is within seconds to minutes, oral allergens take 5-60 min depending on stomach contents

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5
Q

Food intolerance vs type I hypersensitivity

A

No IgE or immune system activation is involved in food intolerance, it is amount dependent (unlike allergies) but it manifests as a difficulty digesting a food resulting often in diarrhea or associated symptoms but not systemic or as severe effects

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6
Q

Type I hypersensitivity rxn mechanism

A

-IgE located on mast cell and basophils cross links with free antigen resulting in degranulation of histamine and inflammatory markers

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7
Q

Type I hypersensitivity effect on airways, GI, and blood vessels

A

Airway - decreased diameter, increased mucus secretion resulting in difficulty breathing and tripoding
GI - Increased fluid secretion and peristalsis of smooth muscle resulting in stomach cramps, vomiting, diarrhea
Blood vessels - Increased capillary permeability and entry of fluid into tissues resulting in edema and loss of blood pressure

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8
Q

Does type I sensitivity result in fever?

A

NO! That’s part of how you can differentiate it from infection

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9
Q

Type I hypersensitivity reaction is somewhat dependent on…

A

…site of mast cell activation, with subcutaneous resulting in angioedema and urticaria, and inhalation resulting in bronchoconstriction, increased mucus secretion

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10
Q

Angioedema

A

Swelling of lips, very common in type I hypersensitivity reaction

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11
Q

Urticaria

A

Hives, wheal and flare reaction, typically itchy

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12
Q

If a patient has a legit allergy to penicillin, what drug class should also be avoided?

A

Cephalosporins

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13
Q

If a patient has a rash response to penicillin, can you use cephalosporins?

A

Yes, safe alternative generally speaking used before other drug types

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14
Q

Any food, sting or bite, medication, or biological activity/factor can potentially trigger this type of hypersensitivity

A

Type I, anaphylaxis

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15
Q

Anaphylaxis definition

A

Serious allergic reaction rapid in onset and may result in death

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16
Q

Anaphylactoid definition

A

Non IgE mediated activation of histamine release from mast cells and basophils (no degranulation) that presents the same clinically and is not distinguishable, treatment is the same as for anaphylaxis

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17
Q

Pruritus definition

A

Itchy tingling often seen around the mouth and face particularly in anaphylaxis

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18
Q

What 2 reactions from anaphylaxis result in death?

A

Respiratory bronchospasm and cardiovascular shock

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19
Q

Biphasic reaction

A

Can occur with type I hypersensitivity, recurrence of symptoms that develops following apparent resolution of initial anaphylactic episode despite no additional exposure to causative agent - requiring that drug treatments be a longer period course up to 10 days

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20
Q

Protracted anaphylaxis

A

Anaphylactic reaction that lasts for hours, days, or even weeks in extreme cases

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21
Q

Anaphylactic episodes can not be predicted on ___ or ___ of progression

A

severity, rate

22
Q

CAB’s of CPR

A

Compressions, airways, breathing

23
Q

Use of trendelenberg in immediate management of type I hypersensitivity

A

Encourage venous return limiting drastic drops in BP

24
Q

Contents of an epipen, contents of IV epi

A

.5 cc of 1:1000 epi

1:10,000 (dilute)

25
Q

H1 blockers function and example

A

Used in type I hypersensitivity to relieve itch and hives , diphenhydramine (benadryl

26
Q

H2 blockers function and example

A

Used in type I hypersensitivity to relieve GI symptoms of anaphylaxis, ranitidine (zantac)

27
Q

Glucocorticoids function and example

A

Used in type I hypersensitivity to prevent biphasic rxn for 7-10 days following anaphylacitic episode, methylprednisolone (solumedrol)

28
Q

Albuterol function

A

Used in type I hypersensitivity to promote bronchodilation

29
Q

Adverse effects of epi to treat type I hypersensitivity reaction

A

Anxiety, palpations, pallor, tremor, frear, restlessness, MI, pulmonary edema,

30
Q

Serum or plasma tryptase test function and results

A

Used in type I hypersensitivity when drawn within first 3 hours of symptom onset, elevations indicate degranulation of mast cells from IgE mediated hypersensitivity reaction

31
Q

How do antibodies work? (3 things

A

Neutralize pathogens, fixate complement to the surface of cells to allow for lysis, bind various cell types such as phagocytes, lymphocytes, platelets, mast cells, and basophils

32
Q

Complement and its 4 actions

A

A group of globulin proteins that act as enzymes to facilitate the immunologic and inflammatory response by increasing vascular permeability, chemotaxis, phagocytosis, and opsonizing the antigen for binding

33
Q

Type II hypersensitivity uses what two types of Ig molecule?

A

IgM, IgG

34
Q

Type III hypersensitivity uses what two types of Ig molecule?

A

IgG, IgM

35
Q

Type II hypersensitivity rxn mech

A

-IgM and IgG bind to antigens covalently bound to the cell surface resulting in complement activation, increased vascular permeability results in antibodies and WBC’s to enter the area of inflammation and lyse/phagocytose cells

36
Q

Type III hypersensitivity rxn mech

A

-Antibodies bound to antigens in circulation form immune complexes that deposit in tissue causing damage and inflammation

37
Q

Type IV hypersensitivity rxn mech

A

-Contact of antigen with pre sensitized T lymphocytes results in macrophage activation and inflammatory reaciton of tissue most often manifested as contact dermatitis

38
Q

Key diff between type II and type III hypersensitivities

A

If the antigen binds to a cell surface or is free floating

39
Q

Type II hypersensitivity examples (7)

A
  • transfusion reactions
  • autoimmune hemolytic anemia
  • goodpasture’s(lung and kidney)
  • graves disease (hyperthyroidsism)
  • myasthenia gravis (neuromuscular weakness)
  • rheumatic fever (post strep infection)
  • erythroblastosis fetalis
40
Q

Direct and indirect coomb’s test and what they measure

A

Direct detects antibodies on RBC cell surface (bound immunoglobins) and a positive is indicative of a hemolytic reaction, indicrect detects antibodies floating freely in circulation (unbound immunoglobins) and a positive indicates that blood is incompatible with another type

41
Q

Erythroblastosis fetalis can be witnessed within even the ___ pregnancy. Also, anytime ___ occurs this does not exclude the possibility of future pregnancies suffering the same disease. What do we treat it with preventativly for the mother?

A

first, conception (even if abortion or ectopic or whatever), rhogam Rh immune globin is given at 28 weeks and within 72 hrs of delivery

42
Q

Rhogam mech of action

A

-Manufactured antibodies that bind to any Rh in the mother’s blood preventing the mother from having her own reaction to it which would result in her developing antibodies that can cross the placenta, while rhogam cannot

43
Q

3 main locations antigen antibody complexes deposit

A

small blood vessels,

joints, glomeruli

44
Q

Type III hypersensitivity examples

A
  • Serum sickness
  • Arthus reaction (localized painful reaction at vaccine antigen injection site)
  • Farmer’s lung
  • systemic lupus erythematosus
  • Post streptococcal glomerulonephritis (untreated strep)
45
Q

3 things almost always seen in a type III hypersensitivity

A

1) skin eruptions such as systemic urticaria
2) fever
3) joint symptoms

46
Q

Lab tests for serum sickness

A
  • Elevated WBC

- Elevated ESR

47
Q

Medication for serum sickness and how should it be distributed, what is one group of patients to never give it to?

A

Prednisone, taper over 10 days so the body begins producing its own glucocorticoid again, diabetics

48
Q

3 examples of a type

iv hypersensitivity

A

Contact dermatitis, tuberculin, granuloma

49
Q

Type IV hypersensitivity reaction mech

A

-Langerhan’s cells on skin process antigen from epidermis and drain to lymph nodes where it is processed by T cells, which then cause the entire skin to become hypersensitive to the contact allergen

50
Q

Patch test

A

Testing method to determine delayed hypersensitivities

51
Q

Why does poison ivy continue to spread beyond contact points (2 reasons)?

A

Delayed spread of the oil to already sensitized skin areas (remember all the skin becomes sensitized) or by scratching with more oils