Overview of anaphylaxis, including management strategy based on the available evidences.

1. Anaphylaxis
Dr Tushar Jagzape,
Additional Professor, Pediatrics
AIIMS, Raipur
8/22/2018 1

2. Case history
• A 14-year-old girl went for a birthday party. After having food in the party
she complained of uneasiness, crampy pain in abdomen, vomiting and
throat tightness. She was a known case of Asthma. When brought to the
emergency department she was having breathing difficulty, oxygen
saturation was 92% and had wheezing. She had rash as shown .
• What is the likely diagnosis?
8/22/2018 2

3. 8/22/2018 3

4. Learning objectives:
• At the end of this class the learner should be able to:
• Define Anaphylaxis and anaphylactoid reaction
• Enumerate common causes of anaphylaxis
• Pathophysiology of anaphylaxis
• Clinical features
• Management
8/22/2018 4

5. Definition:
• Anaphylaxis is an acute, severe, life-threatening allergic reaction in
presensitized individuals, leading to a systemic response caused by
the release of immune and inflammatory mediators from basophils
and mast cells.
• At least 2 organ systems are involved, such as the skin, the upper and
lower airways, and the cardiovascular, neurologic, and GI systems, in
this order of priority or in combination.
• Similar symptoms caused by nonimmunologic mechanisms are
termed anaphylactoid reactions/ pseudoanaphylaxis.
8/22/2018 5

6. 8/22/2018 6

7. Common causes
• Food:
• Pea nut, milk, egg, fish, tree nuts
and food additives.
• Medications:
• ß- lactam antibiotics, NSAIDS
• Venom:
• Hymenoptera
• Natural rubber latex
• Occupational allergens
• Diagnostic agents like
radiocontrast media.
• Immunomodulators and
recombinant biological agents
• Infliximab, rituximab, omalizumab
• Physical factors
• Exercise, cold, heat and sunlight
8/22/2018 7

8. Classification: World Allergy organization allergic disease
resource center: anaphylaxis
1. Anaphylaxis:
immunologic, particularly IgE-mediated reactions
2. Nonallergic anaphylaxis:
clinically identical to anaphylaxis; however, not immunologically
mediated
8/22/2018 8

9. Classification of immediate type life threatening allergic
reactions
1. IgE antibody mediated systemic anaphylaxis
2. IgE-mediated, local, life threatening laryngeal obstruction.
3. Immunologic but not IgE mediated anaphylaxis
4. Munchausen anaphylaxis: real or simulated factitious anaphylaxis
5. Anaphylactoid : non Ig E mediated
6. Idiopathic anaphylaxis: Cause cannot be identified.
8/22/2018 9

10. Epidemiology and pathogeneis
• Estimated prevalence between 1% and 17% of the total US
population, and 0.002% of the population may die from an
anaphylactic reaction.
• Other studies 0.05-2%
• Food allergies more common in children.
• Adults drug allergies more common.
8/22/2018 10

11. 12
Pathogenesis
8/22/2018

12. • Tachycardia,
anxiety, mucus
hypersecretion
• Bronchospasm,
uterine cramsps
• Systemic
• Inflammatory
response.
• Vasodilation,
increase
permeability and
myocardial
dysfunction
Degranulation of
mast cells and
basophils
Increase platelet
aggregation and
recruitment of
more cells
Activation of
autonomic
nervous system
Altereed smooth
muscle tone –
8/22/2018 13

13. Clinical manifestation
• Cutaneous
• Urticaria and angiedema
• Flushing
• Pruritus without rash
• Respiratory
• Dyspnea, wheeze
• Upper airway angioedema
• Rhinitis
• Dizziness, syncope, hypotension
• Abdominal
• Nausea
• Vomiting
• Diarrhea
• Cramping pain
• Miscellaneous
• Headache
• Substernal pain
• seizure
Biphasic and atypical presentation in some patients. May be seen
upto 78 hours.8/22/2018 14

14. Risk factors
• Atopy
• Route of administration:
parenteral vs oral
• Previous history of anaphylaxis
• Uncontrolled asthma
• Gender (< 15 year males)
• Higher socioeconomic status
• Age: infants, adolesecents,
young adults and elderly.
• Coomorbiditis
• Medications: sedatives,
hypnotics, ACE inhibitors and ß
blockers.
• Other factors: stress, pregnancy,
menses, acute infection,
occupation
8/22/2018 15

15. Common D/D
• Acute urticaria
• Acute asthma
• Syncope
• Panic attack
• Cardiovascular event (MI, PE)
• Neurologic event(seizure, stroke)
8/22/2018 16

16. Laboratory tests for diagnosis of anaphylaxis
• Serum tryptase: peak 60-90 min and persists for 6 hour.
• Plasma histamine: rise within 5-10 min and remain elevated for 30-60 min.
• 24 hour urinary histamine metabolite: elevated for upto 24 hour.
• Plasma free metanephrine: rule out pheochromocytoma.
• Serum serotonin: rule out carcinoid syndrome.
• Urinary 5 hydroxyindoleacetic acid, vasointestinal hormonal polypeptide panel :
rule out vasoactive polypeptide tumors.
8/22/2018 17

17. Evaluation of potential triggers for an anaphylactic
episode
• Allergen skin tests
• Percutaneous
• Intradermal
• Allergen specific serum IgE levels
• Quantitative ELISA
• Allergen challenge tests
• Foods or medications
• Emerging test:
• basophil activation test
• Other challenge tests
• Exercise, cold, heat, sunlight.
8/22/2018 18

18. Management:
• Epinephrine
8/22/2018 19

19. • Assessment : BLS
• Secure airways, maintain circulation.
• Give epinephrine: Dose and route
IM (1: 1000) IV / IO (1: 10,000) Endotracheal (1: 1000)
Children 0.01mg/kg (Max 0.3 mg) 0.01ml/kg (Max 1mg ) 0.1 mg/kg to max of
2.5mg diluted in 5-10
ml of sterile water
Adult 0.2 to 0.5 ml 1mg 2-2.5 mg diluted in 5-
10 ml of sterile water
Repeat dose 5-15 min 3-5 min 3-5 min
8/22/2018 20

20. • Oxygen for hypoxia.
• IV fluids for hypotension : 30ml/kg within 1st hour.
• Nebulization with salbutamol:
• children: 0.15 mg/kg nebulized every 20 minutes for 3 doses, then 0.15 to 0.3 mg/kg every 1-
4 hours when required;
• adults: 1.25 to 5 mg nebulized every 20 minutes for 3 doses, then every 1-4 hours when
required
8/22/2018 21

21. • H1 and H2 antagonists :
• Children: Diphenhydramine 1-2 mg/kg intravenously/intramuscularly;
• Adults: 25-50 mg intravenously/intramuscularly.
-and-
• Ranitidine: children: 1 mg/kg intravenously given over 5 minutes; adults: 50 mg
intravenously given over 5 minutes.
• Vasopressors: Iv epinephrine infusion.
• Glucagon: Adjunct along with epinephrine in patients on ß-blockers and CAD.
• Corticosteroids*:
• methylprednisolone: children and adults:1-2 mg/kg/day intravenously
• prednisone: children and adults: 0.5 to 1 mg/kg/day orally
• Atropine
8/22/2018 22

22. Prevention:
• Primary prevention:
• Avoidance of insect bite/ sting
• Secondary prevention:
• Avoidance of re-exposure.
• Epipen
• Immunotherapy.
8/22/2018 23

23. 8/22/2018 24

24. Summary
• Anaphylaxis is a life threatening event and a medical emergency.
• It could be IgE mediated or non – Ig E mediated (anaphylactoid).
• Food is the most common cause of anaphylaxis in children.
• Skin manifestation followed by respiratory symptoms are commonest.
• Treatment : Epinephrine.
• Prevention is possible.
8/22/2018 25

25. Bibliography
• BMJ Best Practice: Anaphylaxis
• Anaphylaxisda practice parameter update 2015. Ann Allergy Asthma
Immunol 115 (2015) 341e384
• Nelson Textbook of Pediatrics.
• Anaphylaxis. Textbook of Allergy for the clinician. P.K. Vedanthan et al.
CRC press.
8/22/2018 26

26. 8/22/2018 27