Anaphylaxis Flashcards
what is anaphylaxis
hypersensitivity reaction type 1
how many types of hypersensitivity reactions is there
4 types
type 1
IgE AB mediated- targeting allergen
Type 2
IgM and IgG AB mediated- targeting “self” Ag
Type 3
Immune complex mediated
Type 4
CD4+ and CD8+ mediated
Type 1 hypersensitivity reaction - Allergic reaction steps
- first exposure to environmental allergen (an other harmless antigen)- inhaled, ingested, injected, direct contact
- predisposed individual- Naive B- lymphocyte induced to produce IgE AB
- sensitization- IgE AB bind to surface of Mast cells and Basophils
- Re-exposure to the allergen
- Reaction- degranulation of mast cells and basophils with release of performed chemical mediators- Histamine, leukotrienes, prostaglandins and others, resulting in a number of effects
spectrum of type 1
Mild- Severe
Local- systemic
what is anaphylaxis
it is an acute, severe, life- threatening allergic reaction that is generalized/ systemic (multi organ), that occurs within seconds to minutes to hours to exposure to a known, or unknown, allergen. it may also be biphasic
anaphylaxis involves multiple systems
organs which anaphylaxis usually occur at
- skin and or mucosa (80%)
- respiratory system
- cardiovascular system
- gastrointestinal system
skin and or mucosa: superficial symptoms
flushing
urticaria (pruritic skin rash)
conjunctival injection
rhinorrhea
skin and or mucosa: deep symptoms
angiodema (painless swelling under the skin, commonly of the tongue, lips and peri-orbital region)
respiratory system: upper airway obstruction (pharynx ,larynx)
visual swelling. difficulty in swallowing, stridor, respiratory distress (increased respiratory rate and increased effort)
respiratory system: bronchospasm and increased mucous production
wheezes, respiratory distress (increased respiratory rate and increased effort)
cardiovascular system
vasodilation
increased vascular permeability
shock
cardiovascular system: vasodilation
leading to a form of distributive shock
cardiovascular system: increased vascular permeability
leading to intravascular depletion and potentially hypovolemic shock
define shock
hypoperfusion, reduced organ perfusion
types of shock
cardiogenic
obstructive
hypovolemic
distributive
what is sepsis
Sepsis is a serious and potentially life-threatening medical condition that occurs when the body’s response to an infection leads to systemic inflammation, widespread tissue damage, and organ dysfunction
shock on the CNS
dizziness, syncope, feeling of impending doom, headache, metallic taste
shock on the Cardiac
compensatory tachycardia, acute cardiac failure (acute drop in cardiac output, acute pulmonary edema, acutely raised JVP), ischemic chest pain dysrhythmias
shock on the respiratory system
compensatory respiratory distress
shock on the peripherals
measured low BP, weak peripheral pulses, warm pink peripherals (in the case of distributive shock)
shock on the gastrointestinal
diarrhoea and cramping (through increased smooth muscle contraction)
common allergens
food
venoms: bites , stings
medication: esp. muscle relaxants, NSAIDs incl. aspirin, antibiotics (penicillin), antivenom, IV contrast media (used in CT scans)
define a biphasic anaphylaxis
there is an initial reaction followed by a delayed. second phase reaction 6-72 hours after the initial reaction without re-exposure to the allergen
life time prevalence of anaphylaxis
1-2% of the population as a whole
epidemiology of anaphylaxis
it is increasing, and has been attributed to the increased number of potential allergens to which people are exposed
allergens common in children
food allergy
allergens common in adults
radiocontrast media
insect stings
medications
if the pulse is absent
advanced life support
if the pulse is present
primary survey
ABCDE approach
first step in treating a patient with anaphylaxis
position the patient appropriately (in a resus, head down, legs raised)
provide supplemental O2
check glucose
insert IV line
apply monitors
Advanced life support treatment
SAMPLE history
high quality CPR ongoing
early defibrillation
ACLS medications
reverse reversible causes of anaphylaxis:
-adrenalin
-fluid resus
-promethazine
plans for primary survey
*adrenalin
*IV fluid bolus
*promethazine (anti- histamine)
*hydrocortisone (steroid)
bolus dose meaning
A bolus dose is a single, relatively large dose of a medication given at one time. In this context, it suggests the administration of epinephrine as a quick and concentrated injection.
when should we repeat adrenalin dose
repeat every 10 minutes if persistent upper airway obstruction (UAO)/ bronchospasm. hypotension
dose of adrenalin >12 yrs
0.5 mg IM
dose of adrenalin 6-12 yrs
0.3 mg IM
dose of adrenalin 2-5 yrs
0.2 mg IM
when do we administer fluid bolus
if SBP<90 mmHg
types of fluid bolus
normal saline 0.9%
ringers lactate
Crystalloid Fluids:
Crystalloid fluids are solutions that contain small particles (crystals) dissolved in water. Normal Saline 0.9% and Ringer’s Lactate are examples of crystalloid solutions commonly used for fluid resuscitation
adrenaline administration in adults
adult: 1-4 IV rapid infusion
adrenaline administration in paeds
20ml/kg
promethazine (antihistamine) usage
not essential in acute setting
promethazine (antihistamine) >12 yrs
25mg IM/IV
promethazine (antihistamine) 6-12 yrs
12.5 mg IM/IV
promethazine (antihistamine) 2-5 yrs
6.25 mg IM/IV
hydrocortisone (steroid) usage
not essential in acute setting
hydrocortisone (steroid) >12 yrs
200mg IV/IM
hydrocortisone (steroid) 6-12 yrs
100mg IV.IM
hydrocortisone (steroid) 2-5 yrs
50 mg IV/IM
further persisting UAO (angioedema)
*nebulized adrenalin (1mg adrenalin: 3mg N/ saline)
*definitive airway:
-endotracheal intubation
-surgical cricothyroidotomy
further persisting bronchospasm
as per status asthmaticus:
- beta 2 agonists (salbutamol) inhaled via metered dose inhaler (MDI)/ nebulizer
status asthmaticus
“Status asthmaticus” refers to a severe and prolonged asthma attack that does not respond adequately to standard treatments like bronchodilators and inhaled corticosteroids
beta 2 agonists
a class of medications that act on beta-2 adrenergic receptors. These receptors are found primarily in the smooth muscle of the bronchi (airways) in the lungs. Beta2 agonists are commonly used in the management of respiratory conditions, particularly those involving bronchoconstriction (narrowing of the airways).
endpoints of resuscitation: airway
attained, maintained and protected by the patient or by you
endpoints of resuscitation: breathing
reduction in respiratory distress and improvement of other clinical features (e.g. wheezes)
SO2> 94%
ETCO2 35- 45 mmHg
PaO2 80-100mmHg
endpoints of resuscitation: circulation
*improvement of signs and symptoms of hypotension
*SBP>90mmHg
* MAP> 65mmHg
* U- output 0.5-1ml/kg/hr
*Improvement of Lactate
how long to we observe an anaphylactic patient
> /= 6 hrs
when to we refer for admission
severe anaphylactic reaction
-severe/ life threatening presentation
-needed fluid bolus
-repeat adrenalin dose required
uncontrolled asthma
discharging an anaphylactic patient
Bio: prescribe adrenalin auto- injector device
psycho: education
social: educate care givers
follow up
allergist
why we administer adrenaline during anaphylaxis
Vasoconstriction and Blood Pressure Elevation:
Adrenaline acts on alpha-adrenergic receptors, leading to vasoconstriction (narrowing of blood vessels). This helps counteract the severe drop in blood pressure (hypotension) that can occur during anaphylaxis. Elevated blood pressure is essential for maintaining blood flow to vital organs.
Bronchodilation:
Adrenaline stimulates beta2-adrenergic receptors in the lungs, resulting in bronchodilation (widening of the airways). This helps alleviate the symptoms of bronchoconstriction, such as wheezing and difficulty breathing, which are common in anaphylaxis.
Reduction of Urticaria and Angioedema:
Adrenaline helps to reduce skin manifestations of anaphylaxis, including urticaria (hives) and angioedema (swelling). This can be crucial in preventing airway obstruction due to swelling.
Stabilization of Mast Cells and Basophils:
Anaphylaxis is characterized by the release of various chemical mediators, such as histamine, from mast cells and basophils. Adrenaline stabilizes these cells, preventing further release of inflammatory substances and mitigating the allergic response.
