anap

1. Anaphylaxis
Debra O’Brien
29/8/12

2. 37 yr old man (PMHx Asthma)
30 minutes itchy red rash over his chest and abdomen
onset while eating dinner in restaurant

3. When is an allergic reaction
considered to be anaphylaxis?

4. When is an allergic reaction
considered to be anaphylaxis?
National Institute of Allergy and Infectious Disease and the
Food Allergy and Anaphylaxis Network.
Anaphylaxis is highly likely when any 1 of the following 3 criteria are fulfilled:
1. Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue, or
both (eg, generalized hives, pruritus or flushing, swollen lips-tongue-uvula) AND at least 1 of the
following:
Respiratory compromise (eg, dyspnea, wheeze-bronchospasm, stridor, reduced PEF, hypoxemia)
Reduced BP or associated symptoms of end-organ dysfunction (eg, hypotonia [collapse], syncope, incontinence)
2. Two or more of the following that occur rapidly after exposure to a likely allergen for that patient
(minutes to several hours):
Involvement of the skin-mucosal tissue (eg, generalized hives, itch-flush, swollen lips-tongue-uvula)
Respiratory compromise (eg, dyspnea, wheeze-bronchospasm, stridor, reduced PEF, hypoxemia)
Reduced BP or associated symptoms (eg, hypotonia [collapse], syncope, incontinence); persistent
gastrointestinal symptoms (eg, crampy abdominal pain, vomiting)
3. Reduced BP after exposure to known allergen for that patient (minutes to several hours):
Infants and children: low systolic BP (age specific) or greater than 30% decrease in systolic BP
Adults: systolic BP of less than 90 mm Hg or greater than 30% decrease from that person’s baseline

5. Anaphylaxis
Acute onset multiple-organ hypersensitivity
some degree of skin involvement appears to be nearly universal
(although often subtle, such as mild erythema)
PLUS
respiratory (throat or chest tightness, breathlessness, wheeze, stridor, hypoxia)
cardiovascular (hypotension, collapse, loss of consciousness)
gastrointestinal (nausea, vomiting, abdominal pain)

6. What are the common triggers?
Venomous stings and bites 30%
Medication (antibiotics, NSAIDs) 22%
Food (nuts, seafood) 18%
Unidentified 25%
Other 5%

7. What are the common triggers?
Venomous stings and bites 30%
Medication (antibiotics, NSAIDs) 22%
Food (nuts, seafood) 18%
Unidentified 25%
Other 5%

8. When do you give Adrenaline?
• “The number one cause of death in anaphylaxis is the failure to
administer adrenaline”
Under-recognized and therefore under-treated
• Several case series have implicated the failure to administer
adrenaline early in the course of treatment as a consistent finding
in anaphylaxis deaths
• Not possible to predict
– severity
– rate of progress
– response to treatment
– risk of biphasic or protracted

9. • Consensus – even mild systemic reactions are best treated
immediately with adrenaline → prevent progression to more
severe symptoms more effectively than any other available
therapies.
• There are NO absolute contraindications to adrenaline use in
anaphylaxis

10. How much Adrenaline?
Adrenaline 0.01 mg/kg of 1:1000 (1 mg/mL)
to a maximum of 0.3-0.5 mg by INTRAMUSCULAR injection
every 3-5 minutes if life-threatening symptoms of hypotension,
respiratory distress or stridor persist.
normal saline 10-20mL/kg boluses for persistent hypotension

11. Adrenaline Infusions
1 mg of adrenaline 1:10,000
inject into 1000mL bag of normal saline
start infusion at 1 mL/min (1 µg/min)
increase rate until resolution of severe anaphylaxis
Or
if you have a central line
6mg in 100 mL of 5% Glucose→ 60 µg/mL
Start infusion at 1 mL/hr (1 µg/min)

12. What is the role of antihistamines?
UpToDate and Cochrane Review
No evidence to support the use of H1 antihistamines in
anaphylaxis
Adjunctive to relieve itching and hives
They DO NOT relieve the other symptoms of anaphylaxis
and
in standard doses do not inhibit mediator release
• 1st vs 2nd generation antihistamines
• H2 antihistamines

13. What is the role of steroids?
UpToDate and Cochrane Review
No evidence to support the use of steroids in anaphylaxis
Adjunctive to prevent the biphasic or protracted reactions
occur in up to 23 percent of adults with anaphylaxis, and up to 11 percent of
children with anaphylaxis.
• Methylprednisolone of 1-2mg/kg
for 3 days without a taper
all biphasic reactions reported to date
have occurred within 72 hours
• Hydrocortisone 4 mg/kg IV or IM
then 2-4mg q6h

14. What is the role of bronchodilators?
Adjunctive treatment of bronchospasm not responsive to
adrenaline
do not prevent or relieve mucosal oedema in the upper airway
or shock, for which the alpha-1 adrenergic effects of adrenaline are
required

15. Should you do any investigations?
Lab tests are not usually required – clinical diagnosis
Helpful when diagnosis of anaphylaxis is unclear
• Total tryptase levels may be tested within 3 hours of
symptom onset.
– peak tryptase level correlated with severity of symptoms.
– normal tryptase levels do not rule out a diagnosis of
anaphylaxis, and are more likely with food-related anaphylaxis
• Histamine levels peak within 10 minutes of onset of
anaphylaxis return to baseline within 60 minutes

16. Which patients need to be admitted?
Admission
• Severe anaphylaxis
• Mild to Moderate anaphylaxis that does not respond promptly
to adrenaline
Vs
Observation
For patients with anaphylaxis which resolves promptly and
completely with treatment → minimum observation period of
4 hours, and prefer a period of 8 to 10 hours, if possible.

17. What is the risk of a biphasic
reactions?
• Occur about 5% of the time
• May occur >24 hours after the initial episode
• Usually less severe than the initial episode
• Possible risk factors include:
1. delayed administration of adrenaline
2. slow response to adrenaline
3. need for repeated doses of adrenaline
4. need for IV fluids

18. Who needs an Epipen?
The mnemonic "SAFE" - four basic action steps suggested
for patients with anaphylaxis who have been treated and
are subsequently leaving the emergency department .
• Seek support
• Allergen identification and avoidance
• Follow-up with specialty care
• ‘Epinephrine’ for emergencies

19. Take Home Messages
• Early recognition
• Early treatment with
adrenaline...know your doses!
• Risk of biphasic reactions
• “SAFE”