Anaphylaxis Due to Airborne Exposure to Latex in a Primigravida

麻醉部 林子富17 March, 2004

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

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 %

No chest tightnessNo wheezingNo apparent change on blood pressureMild increase in heart rateNo skin reactions: itching, rash, flushing, hives, urticaria…No other medications used other than piton-s, ergotamine and intrathecal marcaine.

Initial Diagnosis

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

Immediate Measures Taken..

Keep maintaining airway with 100 % oxygen.Wash hands thoroughlyBricanyl and epinephrine via nebulizationVena 30 mg IVMethylprednisolone 40 mg IVEpinephrine 10 μg IVQuick resolution of symptoms

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.

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

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

Irritant Contact DermatitisThe 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.

Allergic Contact Dermatitis

Type IV cell-mediated hypersensitivity reactionA reaction begins within 48-72 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 threateningFar more common than a type I reaction

Type I IgE-mediated Hypersensitivity Reaction

Severe, may lead to significant morbidity and mortalityOn 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

Mild Reactions

Airborne exposure or direct contact with the skinSymptoms usually develop 30 min after exposure.

• Local urticaria• conjunctivitis• Rhinitis• Bronchoconstriction

Severe ReactionsOccur 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.

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.

High Risk Groups

Health care workersNonhealth care workers with occupational exposure to latex such as hairdressers, food-service workers…Patients with atopic backgroungsChildren with spina bifida or genitourinary abnormalities– Hev b 1 is the major allergen for children with spina bifida.

Prevalence

Latex sensitization• 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

Latex-Fruit Syndrome

• Banana• Avocado pear• Strawberry• Guava• Citrus fruit

• Peach• Mango• Watermelon• Cherry

Some fruits contain cross-reacting proteins with latex

Signs of allergic reactions• Pruritus • Tightness in the throat

• Breathing difficulty• Hives

In one study, 86 % (49 of 57) of fruit-allergic patients were alsoallergic to latex compared with 4 % (2 of 50) of controls.

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

Management

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

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.

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.

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

Latex-safe protocolIdentification of at-risk groupsHave procedures performed as the first case in the morningWash hands thoroughly to remove any traces of powder or latexBest to use nonpowdered gloves to avoid all latex aeroallergensNonlatex materials– Syringe without a latex stopper– Medication from ampoules

• Avoid vials with latex stoppers

Avoid premixed syringes of drugs

Future Therapies

Subcutaneous desensitization with latex extract to build up toleranceLatex allergy desensitization by exposure protocolModifications with latex proteins result in decreased IgE binding activityTreatment with monoclonal anti-IgE antibody

Conclusion

Awareness of latex allergyUse latex-free gloves or nonpowered gloves with small latex protein count

References

Hepner, David L. at al. Latex allergy: an update. Anesth Analg, Volume 96(4). April 2003. 1219-1229.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 2003,1204-1205.Eckhout, Gifford V. Jr., M.D.*; Ayad, Sabry M.D. Anaphylaxis Due to Airborne Exposure to Latex in a Primigravida. Anesthesiology,95(4),October2001,1034-1035.