1. Anaphylaxis Due to Airborne Exposure to Latex in a Primigravida
麻醉部 林子富
17 March, 2004

2. History Taking
A 32-yr-old gravida 1 para 0 patient at 38 weeks’ gestational age
premature rupture of membrane
Abnormal fetal presentation
With a history of asthma
Allergic reactions to seafoods
Had no previous surgery

3. Presenting Symptoms Approximately 35 min after spinal injection Cough
Tightness in the throat
Rhino-conjunctivitis
Sneezing
Ocular itch
Tearing
Conjunctival congestion
Breathing difficulty
Restlessness
Decreased SpO2 to 72 %

4. No chest tightness
No wheezing
No apparent change on blood pressure
Mild increase in heart rate
No skin reactions: itching, rash, flushing, hives, urticaria…
No other medications used other than piton-s, ergotamine and intrathecal marcaine.

5. Initial Diagnosis
Based on symptoms and signs suggestive of an anaphylactic reaction after unintentional exposure to airborne latex particles…

6. Immediate Measures Taken..
Keep maintaining airway with 100 % oxygen.
Wash hands thoroughly
Bricanyl and epinephrine via nebulization
Vena 30 mg IV
Methylprednisolone 40 mg IV
Epinephrine 10 μg IV
Quick resolution of symptoms

7. Natural Rubber Latex
NRL(cis-1,4-polyisoprene) is a milky fluid obtained from Hevea brasiliensis tree.
Incidence of latex anaphylaxis increased since the 1980s because of Universal Precautions.
Hev b proteins are major allergens in latex.
Hev v 5 sensitization is common among health care workers.
Cornstarch acts as a carrier for latex allergens by binding to latex proteins.

8. Natural Rubber Latex Mandate by FDA since Sep. 30 1998
“Caution: The packing of this product contains natural rubber latex which may cause allergic reactions”
Labeling statements relating to “hypoallergenic” are prohibited.
Products containing latex
Urinary catheter
Tourniquet
Rubber plunger of syringe
IV tubing
Tape
ECG pad

9. Reactions Associated with Latex
Latex sensitization
Presence of IgE antibodies to latex
Without clinical symptoms
Latex allergy
Any immune-related reaction to latex
Associated with clinical symptoms

10. Irritant Contact Dermatitis
The most common reaction that may develop minutes to hours after exposure to latex-powered gloves or chemicals.
The alkaline pH of powered gloves is the cause of this reaction.
May occur on the first exposure, usually benign and not life threatening.
Similar to a localized abrasion with a loss of the epidermoid skin layer, leading to soreness, pruritus, and redness.
Extent of the reaction depends on the duration of ezposure and skin temperature.

11. Allergic Contact Dermatitis
Type IV cell-mediated hypersensitivity reaction
A reaction begins within h on a repeated exposure, leading to erythema with vesicles and scales.
Result from T-cell-mediated sensitization to the addictives of latex (antioxidant or rubber accelerators).
Not life threatening
Far more common than a type I reaction

12. Type I IgE-mediated Hypersensitivity Reaction
Severe, may lead to significant morbidity and mortality
On first exposure
Patients are sensitized
IgE specific for Hev b
CD4+ T-helper cells are activated to induce B cells to form secreting plasma cells
IgE then binds to the surface of mast cells and basophils
Upon reexposure
Hev b proteins cross-link membrane-bound IgE, leading to degranulation of the sensitized mast cells and basophils.
Preformed mediators, histamine, proteases and prostaglandins are then released
A reaction ranging from local urticaria to a full-blown anaphylactic reaction

13. Mild Reactions Airborne exposure or direct contact with the skin
Symptoms usually develop 30 min after exposure.
Local urticaria
conjunctivitis
Rhinitis
Bronchoconstriction

14. Severe Reactions
Occur shortly after parenteral or mucous membrane exposure
Flushing
Vasodilatation
Severe bronchospasm
Increased vascular permeability with edema
Cardiovascular collapse
Anaphylaxis during anesthesia
Cardiovascular symptoms (73.6%)
Cutaneous symptoms (69.6%)
Bronchospasm (44.2%)
Only a severe reaction may be recognized, and the only presenting sign may be cardiovascular collapse.

15. Other conditions resembling anaphylaxis
Histamine release with skin manifestations
Morphine
Atracurium
Bronchospasm
Secondary to an asthmatic attack
inadequate anesthesia
Pneumothorax, pulmonary aspiration
Sudden cardiovascular collapse
Acute MI
High spinal anesthetic
The medical history, the timing of the event, and the clinical presentations…Latex should always be considered in the differential diagnosis when an episode of perioperative anaphylaxis occurs.

16. High Risk Groups Health care workers
Nonhealth care workers with occupational exposure to latex such as hairdressers, food-service workers…
Patients with atopic backgroungs
Children with spina bifida or genitourinary abnormalities
Hev b 1 is the major allergen for children with spina bifida.

17. Prevalence Latex sensitization Latex allergy
Less than 1 % in a nonatopic normal population
3 % ~ 12 % in health care workers
12.5 % in anesthesiologists
Adult anesthesiologist > pediatric anesthesiologist
Latex allergy
In individuals who are atopic, the risk is increased if they had a previous surgery.
2.4 % in anesthesiologists
No increased risk with age, sex, or race
Exposure is the single most significant factor

18. Latex-Fruit Syndrome
Some fruits contain cross-reacting proteins with latex
Banana
Avocado pear
Strawberry
Guava
Citrus fruit
Peach
Mango
Watermelon
Cherry
Signs of allergic reactions
Pruritus
Tightness in the throat
Breathing difficulty
Hives
In one study, 86 % (49 of 57) of fruit-allergic patients were also
allergic to latex compared with 4 % (2 of 50) of controls.

19. Diagnosis A focused history or PE followed by a positive in vitro test
Signs and symptoms suggestive of mast cell activation and release of mediators
hypotension
bronchospasm
laryngeal edema
flushing
urticaria
difficult hand ventilation
increased peak inspiratory pressure
expiratory wheezes
up-sloping of the EtCO2 tracing
tachycardia

22. Management
Discontinuation of the potential trigger and of the anesthetic drug
Latex gloves being used ?
Recent medication?
Blood product?
No further medications, other than those required for the treatment of anaphylaxis, should be given.

23. Management
Airway maintenance with 100 % oxygen, IV fluid to sustain blood pressure, and resuscitation medications.
Epinephrine is the most important medication for the treatment of anaphylaxis.
[alpha]-agonist properties: sustain BP
[beta]2 effect : relieving bronchoconstriction
Dose and route depends on the severity of the episode:
0.2 – 0.5 mg SC or IM
5-10 μg IV (0.1 μg/Kg)
In the presence of cardiovascular collapse, 0.1 – 0.5 mg IV should be promptly administered.

24. Management Other useful medications
Antihistamines (diphenhydramine 0.5–1 mg/kg IV or IM)
Bronchodilators (albuterol and ipratropium bromide via nebulization)
Corticosteroids (methylprednisolone 0.5 mg/kg)
not the first line of treatment because of their prolonged onset
beneficial for delayed and late reactions.
Once the initial event is treated and the patient is medically stable, a serum tryptase should be drawn, and an allergy consultation should be obtained.

25. Prevention Cornerstone in the management of latex sensitization
Latex avoidance in health workers
Decreased latex specific IgE levels
Decreased allergic symptoms
Although skin-prick test remained + 2 yrs after avoidance

26. Latex-safe protocol Identification of at-risk groups
Have procedures performed as the first case in the morning
Wash hands thoroughly to remove any traces of powder or latex
Best to use nonpowdered gloves to avoid all latex aeroallergens
Nonlatex materials
Syringe without a latex stopper
Medication from ampoules
Avoid vials with latex stoppers
Avoid premixed syringes of drugs

27. Future Therapies
Subcutaneous desensitization with latex extract to build up tolerance
Latex allergy desensitization by exposure protocol
Modifications with latex proteins result in decreased IgE binding activity
Treatment with monoclonal anti-IgE antibody

28. Conclusion Awareness of latex allergy
Use latex-free gloves or nonpowered gloves with small latex protein count

29. References
Hepner, David L. at al. Latex allergy: an update. Anesth Analg, Volume 96(4). April
Eckhout GV, Ayad S. Anaphylaxis due to airborne exposure to latex in a primigravida. Anesthesiology 2001; 95: 1034–5.
Hepner, David L. MD; Castells, Mariana C. Clinical Manifestations of Latex Anaphylaxis During Anesthesia Differ from Those Not Anesthesia/Surgery-Related. Anesth Analg,97(4) October 2003,
Eckhout, Gifford V. Jr., M.D.*; Ayad, Sabry M.D. Anaphylaxis Due to Airborne Exposure to Latex in a Primigravida. Anesthesiology,95(4),October2001,