Anaphylaxis Flashcards
What is a hypersensitivity reaction?
Inappropriate response to harmless molecule
Type 1 hypersensitivity
- interval between reaction:
- effector cells:
- target\antigen:
- examples:
- <30 min to 2\12hours
- IgE
- pollen\food\venom\ drugs
- anaphylaxis, uticaria, rhinitis, asthma
Type 2 hypersensitivity
- interval between reaction:
- effector cells:
- target\antigen:
- examples:
- variable
- IgG, IgM, IgA
- RBC & platelet
- Rh incompatiability, thrombocytopnia, goodpasture syndrome
Type 3 hypersensitivity
- interval between reaction:
- effector cells:
- target\antigen:
- examples:
- 1 to 3 weeks after exposure
- complement
- vessels, spleen, kidney, lung
- serum sickness, hypersensitivity pneumonitis
Type 4 hypersensitivity
- interval between reaction:
- effector cells:
- target\antigen:
- examples:
- 2 to 7 days after exposure
- t-cell lymphocyte
- MTB - chemicalls
- contact dermaitits, tb skin reaction, graft vs host disease
allergic rhinitis and allergic asthma have a combination of
Type 1 and type 4 hypersensitivity reactions
Autoimmunity is associated with which type of hypersensitivity reaction
Type 2
What is goodpasture syndrome?
IgG and IgA response against proteins in the BM of kidney + lung
Wnich of the hypersensitivity reactions is more sever and associated with systemic disease
Type 3
Name a drug that causes
- type 2:
- type 3:
- type 4:
- quinidine
- cefaclor
- neomycin
What is the prototype of
- type 1
- type 4
- anaphylaxis
- ivy posioning
Differentiate bteween type 2 and type3
- antigens on specific structure
- antigens and antibodies all over the body
Mysthenia gravis is which type of antibody?
Type 2
What is the MOA in type 3
Complexes swim in the circulation and go to ceratain organs (joint synovium, kidney glomeruli, lung aleveoli)
How to treat type 4 hypersensitivity
Avoid trigger - steroidal topical treatment
MOA of type 4 hypersensitivty
Allergen on the skin > APC Tcells identify > inflammatory cascade > itching and erythemia
What is anaphylaxis
Multiorgan system reaction from chemical mediators of (mast cells) + (basophils)
What is the cause, effector, the mediator in type 1 hypersensitivity?
- allergen
- IgE on mast cell
- histamine
What are the effects of histamine in anaphylaxis shock?
- respiratory: bronchospasm & increased mucus secretion > SOB, tightness, wheeze, stridor, hoarseness, cough
- GI: abdo pain, diarrhea
- CNS: lightheadidness, loss of concisousness, headache, anxiety
- vasodilation: Edema
- ithciness\rash
When to consider patient having anaphylaxis “symptoms wise”
Two systems are affected
- SOB
- diarrhea
What are the most common in patient and outpatient causes of anaphylaxis?
- food: outpatient
- drug: inpatient
Name non-immunological causes of anaphylaxis?
Exercise
Direct mast cell degranulation
What is the best treatment of anaphylaxis?
Prevention
- avoid trigger
- patient education
- self administration of epinephrine
What are the medications used in mild to moderate anaphylaxis?
Antihistamine (diphenhydramine)
What medications to use in severe symptoms “trouble breathing or swallowing
Epinephrine “CVS\respiratory”
ABCD in anaphylaxis should be along with:
Epinephrine
In a patient with cardiac arrest who you’ve aldready adminsterd IV epinephrine and required another dose, what will you give
IM epinephrine
What is the role of epinephrine
Vasoconstrictor (Alpha 1 agonist)
- increase BP
- decrease edema
What is the second line for anaphylaxis?
Antihistamine (diphenhydramine)
In a patient with cardiac arrest who you’ve aldready adminsterd IV epinephrine and required another dose, what will you give
IM epinephrine
What is the second line for anaphylaxis?
Antihistamine (diphenhydramine)
Why is rantidine usually raken? (H2 antagonist)
To enhance effect oH1 antagonist
What to do for patient with respiratory distress in anaphylaxis?
Give b2 adrenergic agonist
“Salbutamol and slameterol”
How to administer salbutamol in anaphylaxis?
5-10 puffs every 20 minutes until symptoms of wheezing or respiratory distress
How to prevent the recurrance of anaphylactic symptoms after an initial remission?
Give corticosteroid
What is biphasic anaphylaxis
Initial remission > 8 to 72 hours anaphylactic symptoms
What is protracted anaphylaxis
Presistance of symptoms for hours\days despite treatment
Who should get an epipen?
1- at risk of anaphylaxis
2- not responding to treatment
3- altered conciousness during allergic reaction
4- living in remote area
When to give epipen 0.3 mg
When then weigth is >25 kg
When to give epipen 0.15
When the weight is 15-25 kg
Where to give the dose of epipen?
Mid outer part of thigh
