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 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.

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 thoroughly Bricanyl and epinephrine via nebulization Vena 30 mg IV Methylprednisolone 40 mg IV Epinephrine 10 μg IV Quick 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 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.

Allergic Contact Dermatitis Type IV cell-mediated hypersensitivity reaction A 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 threatening Far more common than a type I reaction

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

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

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.

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 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.

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

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.

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 drug Latex 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 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

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

Conclusion Awareness of latex allergy Use 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.