2. Anaphylaxis: Acute
diagnosis
Anaphylaxis is an acute, potentially life-threatening, systemic
hypersensitivity reaction caused by the sudden release of mast
cell mediators . It most often results from immunoglobulin E
(IgE)-mediated reactions to foods, drugs, and insect stings, but
any agent capable of inciting a sudden, systemic degranulation
of mast cells can induce it .
3. Anaphylaxis
It can be difficult to recognize because
it can mimic other conditions and is
variable in its presentation
5. PREVALENCE
In industrialized countries- is between
0.05 and 2 percent in the general
population
In the United States-is at least 1.6
percent, based on strict clinical
diagnostic criteria
6. DEFINITION
Anaphylaxis is defined as a serious
allergic or hypersensitivity reaction
that is usually rapid in onset and may
cause death .
7. Pathogeneses
Most anaphylactic episodes have an
immunologic mechanism involving IgE.
Foods are the most common cause in
children, while medications and insect stings
are more common causes in adults. The
table provides a more comprehensive list of
potential anaphylaxis causes, categorized
by causative mechanism
11. Types of anaphylaxis
Acute systemic reactions involving IgE-dependent
mechanisms.
●Acute systemic reactions that occur due to direct
(nonimmunologic) release of histamine and other mediators
from mast cells and basophils, formerly called "anaphylactoid
reactions" (eg, after exercise, exposure to cold, administration
of radiocontrast media, etc).
●Acute systemic reactions without any obvious cause or
mechanism (idiopathic anaphylaxis). (See "Idiopathic
anaphylaxis".)
12. SYMPTOMS AND SIGNS
Common presentations anaphylaxis include the following:
Skin and mucosal symptoms and signs- in up to
90 percent of episodes, including generalized hives, itching or
flushing, swollen lips-tongue-uvula, periorbital edema, or
conjunctival swelling. However, urticaria, flushing and itching
may have resolved by the time the patient reaches a medical
facility, so it is important to ask about skin findings at the start
of the reaction.
13. SYMPTOMS AND SIGNS
●Respiratory symptoms and
signs, -in up to 85 percent of
episodes, including nasal discharge,
nasal congestion, sneezing, itching of
the throat and ear canals, change in
voice quality, sensation of throat
closure or choking, stridor, shortness
of breath, wheeze, or cough.
14. SYMPTOMS AND SIGNS
●Gastrointestinal symptoms and
sign-in up to 45 percent of episodes,
including nausea, vomiting, diarrhea,
and crampy abdominal pain.
15. SYMPTOMS AND SIGNS
●Cardiovascular symptoms and signs,
-in up to 45 percent of episodes,
including hypotonia (collapse),
syncope, incontinence, dizziness,
tachycardia, and hypotension
16.
17. Range of severity
Anaphylaxis is unpredictable
Fatal anaphylaxis is rare [14].
Risk factors vary depending upon the
trigger and include older age
18. Fatal anaphylaxis
In a series of 164 cases of fatal anaphylaxis, the median time
interval between onset of symptoms and respiratory or
cardiac arrest was 5 minutes in iatrogenic anaphylaxis (usually
due to anesthetics, intravenous medications, and contrast
media), 15 minutes in stinging insect venom-induced
anaphylaxis, and 30 minutes in food-induced anaphylaxis
19. DIAGNOSIS
is based primarily upon
clinical symptoms and signs
as well as a detailed description of the
acute episode
including antecedent activities
events occurring within the preceding
minutes to hours
20. NIAID/FAAN diagnostic
criteria —
In 2006, diagnostic criteria for
anaphylaxis were published by a
multidisciplinary group of international
experts and representatives from 13
professional, governmental, and lay
organizations.
22. Criterion 1
— Acute onset of an illness
(minutes to several hours)
involving the skin, mucosal tissue,
or both (eg, generalized hives,
pruritus or flushing, swollen lips-
tongue-uvula) and at least one of
the following:
23. Criterion 1
Respiratory compromise (eg, dyspnea,
wheeze/bronchospasm, stridor, reduced peak
expiratory flow, hypoxemia)
OR
●Reduced blood pressure (BP) or associated
symptoms and signs of end-organ malperfusion
(eg, hypotonia [collapse], syncope, incontinence)
Note that skin symptoms and signs are present in up to 90 percent of anaphylactic episodes.
This criterion will therefore frequently be helpful in making the diagnosis.
24. Criterion 2
Two or more of the following that
occur rapidly after exposure to a
likely allergen for that
patient (minutes to several hours):
25. Criterion 2
Involvement of the skin-mucosal tissue (eg, generalized hives,
itch-flush, swollen lips-tongue-uvula).
●Respiratory compromise (eg, dyspnea,
wheeze/bronchospasm, stridor, reduced peak expiratory flow,
hypoxemia).
●Reduced BP or associated symptoms and signs of end-organ
malperfusion (eg, hypotonia [collapse], syncope,
incontinence).
●Persistent gastrointestinal symptoms and signs (eg, crampy
abdominal pain, vomiting).
26. Criterion 3
Reduced BP after exposure to a
known allergen for that
patient (minutes to several hours):
27. Criterion 3
Reduced BP in adults is defined as a systolic BP of
less than 90 mmHg or greater than 30 percent
decrease from that person's baseline.
●In infants and children, reduced BP is defined as
low systolic BP (age-specific)* or greater than 30
percent decrease in systolic BP.
* Low systolic BP for children is defined as:
•Less than 70 mmHg from 1 month up to 1 year
•Less than (70 mmHg + [2 x age]) from 1 to 10
years
•Less than 90 mmHg from 11 to 17 years
28. other
There will be patients who do not fulfill any of these
criteria but for whom the administration
of epinephrine is appropriate. As an example, it
would be appropriate to administer epinephrine to a
patient with a history of severe anaphylaxis to
peanut who presents with urticaria and flushing
that developed within minutes of a known or
suspected ingestion of peanut
29. Laboratory testing
Tryptase
Histamine
both are released almost exclusively by mast cells and
basophils and may be transiently elevated in patients with
anaphylaxis.
measurement of mediators is not included in the diagnostic
criteria.
The blood sample for tryptase should be obtained within 15
minutes to 3 hours of symptom onset
30. DIFFERENTIAL DIAGNOSIS
Approximately 40 other diseases and conditions might
need to be considered in the differential diagnosis of
anaphylaxis
acute generalized urticaria
and/or angioedema,
acute asthma exacerbations
syncope/faint
anxiety/panic attacks
31. Emergency treatment
Act fast – Patients with anaphylaxis should be
assessed and treated as rapidly as possible as
respiratory or cardiac arrest and death can occur
within minutes. Anaphylaxis appears to be most
responsive to treatment in its early phases, before
shock has developed, based on the observation that
delayed epinephrine injection is associated with
fatalities. (See 'Immediate management' above.)
●Treatment tables for adults and children –
Initial management is summarized in rapid
overview tables for adults (table 1) and children
(table 2). (See 'Immediate management' above.)
32. Treatment
Epinephrine is lifesaving
There are no absolute
contraindications to epinephrine use,
and it is the treatment of choice for
anaphylaxis of any severity
Ensure the route and dose
of epinephrine are correct ( IM
injection into the mid-outer thigh )
Indications for large-volume fluid
resuscitation
33. Treatment
Oxygen and bronchodilators for residual
respiratory symptoms
Indications for IV epinephrine(IV epinephrine is
indicated for patients with profound hypotension or symptoms
and signs suggestive of impending shock (dizziness,
incontinence of urine or stool) who do not respond to initial
IM injections of epinephrine and fluid resuscitation
Indications for admission – We advocate for admitting all
patients with severe anaphylaxis (ie, significant respiratory or
cardiovascular symptoms), as well as patients who do not
respond promptly to IM epinephrine, require more than one
dose of epinephrine, or received epinephrine only after a
significant delay (>60 minutes), as these features may be risk
factors for recurrent symptoms (ie, a biphasic reaction
34. treatment
Follow-up care – Patients successfully treated for
anaphylaxis should be discharged with a personalized, written
anaphylaxis emergency action plan,
an epinephrine autoinjector; written information about
anaphylaxis and its treatment; and referral to an allergist for
further evaluation. It is important to make all efforts to
confirm the cause to reduce the risk of recurrence.
Anaphylaxis action plans for patients of any age (Food Allergy
& Anaphylaxis Emergency Care Plan) and specifically for
children
36. Long-term management of patients
with anaphylaxis
Ongoing education – Patients (and, for
children, their families and caregivers) should be
taught to recognize the early symptoms of
anaphylaxis and to inject epinephrine promptly.
They should be counseled regularly that
epinephrine injection is the only appropriate
emergency treatment for anaphylaxis. For patients
with confirmed anaphylaxis, evaluation to
determine the responsible trigger and education
about specific allergen avoidance are essential. This
is an ongoing, long-term process that should be
continued at each follow-up visit
37. 37
EpiPen
Advantages
– Auto-Injector
system delivers pre-
measured dose of
epinephrine
– No preparation
needed
Note:
No other device may
currently be used by
persons completing
this training.
