week 9 anaphylaxis Flashcards
what is the definition of anaphylaxis?
any acute onset illness with typical skin features (urticarial rash, erythema/flushing, angiodema) plus the involvment of respiritoy and or cardiovascular or persistant GI symptoms
or actue onset of hypotenstion/bronchospasm/upper airway obstruction
what is an antigen?
substance the induce the formation of antibodeis
what are antibodies?
protective protien substances that bind to an antigen to facilitte antigen nuterlisation
what are immunolgloblins?
large glycoprotiens that are prodcued by plasma cells that respond to antigenic stimulation
what are the two key immunoglobilins in an anaphylactic reation?
IgE and IgG
what are mediators?
protiens that caused a number of psyiological responses
remain inactive untill triggered
what are the main mediatrs involved in anaphylaxis?
histamine
platlet aggregating factors PAF
Luekotrienes
what is an allergic response?
Protective reaction however becomes oversensitive that may be directed to harmless antigens
what is an allergen?
any antigen that causes an allergic response
what prodcuces a type one allergic reaction?
mediated through IgE where mast cells or basophils are involved - target reactions can have organ involvement causing anaphylactic reaction
what is the age group with the highest rates of anapylaxis?
children under 5 years old
what is the mortality rate of an anaphylaxis reaction?
3%
what are the pathopysiology steps in an anaphylactic reaction?
first exposure to anitgen
stimulates b-lymphocytes produced IgE antibodeis
Second exposure
Ige attached to mast cell and basophil membranes
mast cell destabilisation
what are the three main actions of mast cell destailisation in an anaphylactic reaction?
Increased capiliary permiability
vasodilation of capilaires and venules
contractions of non-vascular smooth muscle
what other immunological response can lead to anaphylaxis?
IgG antigen coplexes
cause copliment and coagulation system activation leading to the degranulation of mast cells and relases of mast and basophil cells
what non-immunological causes can trigger anaphylaxis?
exercise, cold weather, medications and other
what does increased capilary membrane lead to?
intravascular fluid leakage leading to odeama, angiodema, larygnal odeama (stridor), bronchial odeama (wheeze) and urticaria (skin)
what is urtacaria?
bumps/hive like welts on the skin
what does vasodilation of capilaries lead to in anaphylaxs\is?
hypotension, relative hypovolema, decreasde pre-load and SV, decreased CO, decreased tissue perfusion, anaerobic metabolism
what does contraction of non-vascular smooth muscles do in anaphylaxis?
bronchospasm, laryngospasm, GIT cramps/discomfort/nausea, vomiting, dioreha
what are the sings and symptoms of anaphylaxis and why do they occur?
Dizziness/alterconcious state - decreased perfusion
palpitations- tachycardia - SNS response to vasodilation/inadeqaute perfusion
SOB
Expiritory wheeze
1 - leukotrines are potent bronchoconstrictors
Lower airway bronchospasm and hypersecretion of mucous
Nausea and vomiting
- smooth muscle constriction
- increased mucous production
shunting of perfusion to other organs
reddened, inflammed skin
reddened inflammed skin
what are the neurological symptoms of an anaphylaxis reaction?
syncope, anxiety, seizure, dizziness, weakness, headache
what are the cardiovascular symptoms of anaphylaxis?
odeama, tachycardia, chest tightness, arythmias, hypotension
what are the respiritory symptoms in anaphylaxis?
wheezeing, stridor, rhinorrhea, angiodema, larayngal odeam, increased mucous, decreased breth sounds, SOB, bronchospasm