Anaphylaxis Flashcards
What is anaphylaxis?
Anaphylaxis is a potentially fatal allergic reaction to a foreign substance known as an antigen
the onset is rapit (~15 min for an insect sting and ~30 min for food ingestion)
the reaction is systemic and primarily involves the skin, respiratory system, CV, and GI Systems.
Anaphylaxis is a type __________ hypersensitivity
what are the stages to developing this type of reaction?
Anaphylaxis is IgE mediaged - Type I hypersensitivity
During the sensitization stage the pt is asymptomatic but the body is developing antibodies (after the first exposure)
Subsequent exposures lead to an anaphylatic response: crosslinking of the IgE leads to the degranulation of basophils and mast cells
What is an anaphylactoid reaction?
an anaphylactoid reaction is not IgE mediated and is the result of direct breakdown of mast cell and basophil membranes
anaphylactoid reactions can occur after a first time exposure
and treatment is the same as for anaphylactic reactions
Substances that can cause an anaphylactoid reaction include:
Radiopaque contrast media (CT contrast, iv flourescein)
aspirin/NSAIDS
opioid narcotics
Vancomycin
Dextrans
Neuromuscular blocking agents
exercise (this is why I don’t do it)
exposure to cold
What are the clinical manifestations for anaphylaxis?
Skin
Upper respiratory
Lower respiratory
pts with what types of underlying conditions are at an increased risk of death?
- Skin
- Flushing, puritis, urticaria, angioedema
- Upper respiratory
- edema of larynx, epiglottis, lips, tongue
- dysphonia, congestion, rhinorrhea, sneezing, itchy eyes, tearing of eyes, fonjunctival injection, stridor, metallic taste
- Lower respiratory
- bronchospasm, throat tightness, chest tightness, hoarseness, wheezing, SOB, cough, hypoxia, asphyxia death
**pts with underlying lung disease are at an increased risk of death
Acute treatment of Anaphylaxis
Airway Constriction
Airway Constriction
- Laryngeal Edema/Broncospasm
- Epinephrine (IM)
- Nebulized bronchodilator
- Oxygen
- Airflow blockage
- intubation
- tracheostomy
What is a Uniphasic reaction?
a Biphasic reaction?
Protraced anaphylaxis
Uniphasic is the most common- the patient has a reaction which resolves after 4 hours
Biphasic- the reaction comes back within 12 hours without exposure to a second antigen
Protracted- the reaction last hours to days. Weeks even!
delayed- begins hours after exposure
**Pt with uncontrolled s/s after 1+ hour should be admitted to the hospital overnight
What are the three criteria for anaphylaxis?
Criteria for diagnosing anaphylaxis
- Acute onset of illness that involves the skin or mucosa AND hypotension or end organ sysem dysfunction
- Rapid onset of s/s (see chart) after exposure to a likely antigen
- Rapid onset of hypotension after exposure to a known allergen
Anaphylaxis treatment for
hypotension:
- Hypotension:
- trendelenburg position
- epinephrine
- volume expanders
- oxygen
**If the pt is epinephrine resistant (because they are on a beta blocker) use Glucagon and vasopressin
Acute treatment of Anaphylaxis
Urticaria
give 25-50 mg IV or IM of diphenhydramine (Benadryl)
Treat Urticaria with
H1R and H2R antihistamines
What is the first line treatment for anaphylaxis?
What is the dose?
what if the patient doesn’t respond after 3 doses?
Epinephrine given IM in the anterolateral thigh is the first line treatment for anaphylaxis
There are no contraindications for giving epi in t he case of anaphylaxis
Dose: Adults 1mg/mL every 5-15 minutes (0.3-0.5 mg)
If the patient doesn’t respond after 3 doses switch to an IV or an IO
What is the proper adult dose for Ratinidine?
Given with diphenhydromine only
50 mg IV
What is the proper adult dose for
Methylprednisolone
125 mg IV
