2. Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to
undesirable reactions produced by the normal immune system, including allergies
and autoimmunity.
HYPERSENSITIVITY
Type I: reaction mediated by IgE antibodies.
Type II: cytotoxic reaction mediated by IgG or IgM antibodies
Type III: reaction mediated by immune complexes.
Type IV: delayed reaction mediated by cellular response.
3. immunoglobulin E (IgE) antibody against soluble antigen, triggering mast cell
degranulation.
TYPE I
4. TYPE II: IgG and IgM antibodies directed against
cellular antigens, leading to cell damage mediated by other
immune system effectors.
5. TYPE III
interactions of IgG, IgM, and, occasionally, IgA1 antibodies with antigen to form
immune complexes. Accumulation of immune complexes in tissue leads to tissue
damage mediated by other immune system effectors.
7. ANAPHYLAXIS
Sever immediate (type I) hypersensitivity reaction.
Acute multi-systemic allergic reaction involving the skin, airway, vascular
system, and GI on exposure to some allergens
Hormones
ā¢ Insulin
ā¢Vasopressin
ā¢ Parathormone
Enzymes
ā¢ Trypsin
ā¢ Chymotrypsin
ā¢ Penicillinase
Pollens
ā¢ Ragweed
ā¢ Grass
ā¢ Seeds
Foods
ā¢ Egg
ā¢ Seafoods
ā¢ peaNuts
ā¢ Grains
ā¢ Beans
ā¢ Cottonseed oil
ā¢ Chocolate
Insect venom
ā¢ Paper wasp
ā¢ Honey bee
Occupational agents ā¢
Rubber products
ā¢ Industrial chemicals
Drugs
ā¢ Penicillin
ā¢ NSAIDS
ā¢ Opioids
ā¢ ACEI
8. PATHOPHYSIOLOGY
a first exposure to an allergen activates a strong TH2 cell response.
It activate B cells specific to the same allergen,
differentiation into plasma cells,
antibody-class switch to production of IgE
(Fc) regions of the IgE antibodies bind to specific receptors on the surface of mast
cells throughout the body.
mast cells are primed for a subsequent exposure and the individual is sensitized to the
allergen.
9.
10. On subsequent exposure, IgE activates the mast cells and triggers degranulation
Preformed components that are released from granules include
histamine,
serotonin
(Increases vascular permeability vasodilation &smooth-muscle
contraction)
Bradykinin
Leukotrienes
prostaglandins
cytokines ( tumor necrosis factor.)(Causes inflammation and stimulates cytokine
production by other cell types
15. Anaphylactoid reactions occur through a direct nonimmune- mediated release of
mediators from mast cells and/or basophils or result from direct complement
activation, but theypresent with clinical symptoms similar to those of anaphylaxis
ANAPHYLACTOID REACTION
16. ā¢ History
ā¢ Physical examination
ā¢ An increase in human Ī± and Ī² tryptase, the predominant mast
cell proteases,
ā¢ Allergy skin test
ā¢ ā¢ Radioallergosorbent test (RAST)
EVALUATION
17. PERIOPERATIVE ANAPHYLAXIS
Anaphylaxis is rare
Anaphylactoid reactions are more common
RISK FACTORS
ā¢ female gender,
ā¢ atopic history,
ā¢ preexisting allergies,
ā¢ previous anesthetic exposures
18. PERIOPERATIVE ANAPHYLAXIS
1.LOCAL ANESTHETICS:
IgE-mediated allergic reactions are usually due tothe paraaminobenzoic acid metabolite from
esters(PROCAINE, CHLORPROCAINE, BENZOCAINE) or methylparaben (a preservative).
2.MUSCLE RELAXANTS:
Succinylcholine contains a flexible molecule that can cross-link twomast cell IgE receptors induce
mast cell degranulation.
D-tubocurarine,doxacurium, atracurium, and mivacurium, are more likely to cause direct mast cell
degranulation
3.OPIOIDS
Rare
Morphine & MEPERIDINE cause non immunological histamine release
Rarely with INDUCTION AGENTS
19. TREATMENT
1. Immediate discontinuation of the anesthetic drugs and early administration of
epinephrine are the cornerstones of treatment.
2. Ensure large bore iv access
Airway support with 100% oxygen will increase oxygen delivery
IV crystalloid (2ā4 l),,peds(20ml/kg)
Epinephrine is the drug of choice
Ī±1 effects help to support the bloodpressure
Ī²2 effects provide bronchial smooth-muscle relaxation.
5- to 10-Ī¼g IV bolus (0.2 Ī¼g/kg) doses for hypotension
0.1- to 0.5-mg IV doses in the presence of cardiovascular collapse.
In Pruritus and urticaria : 0.3 to 0.5 mL of 1:1000 (1.0mg/mL) epinephrine SC or IM
20. Histamine blockers
Diphenhydramine 0.5ā1 mg/kg
Ranitidine 150 mg ,
Bronchodilators (e.g., ipratropium bromide nebulizers),
corticosteroids (e.g., hydrocortisone 1ā5 mg/kg) decrease the airway swelling
Extubation should be delayed, because airway swelling and inflammation
may continue for 24 h.