Page 1802 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 128: Anaphylactic and Anaphylactoid Reactions 1271

ETIOLOGY life-threatening reactions occur with a frequency of less than 0.1%
with conventional high-osmolality RCM. 26,27 With the development of
The various triggers of anaphylaxis are grouped according to the mecha- lower-osmolality RCM, the overall risk of anaphylactoid reactions has
nism by which they cause anaphylaxis (Table 128-2). Overall drugs and decreased. 28
foods are the most frequent causes of anaphylaxis. 16 Systemic allergic reactions to insect stings are reported by up to 3%
Foods are arguably the most common cause of anaphylaxis in the of adults, and almost 1% of children who have been stung. 29,30 At least
outpatient setting. Food allergens account for 30% of fatal cases. 17,18 The 50 fatal reactions to an insect sting occur each year in the United States.
prevalence of food-induced anaphylaxis is increasing. The most fre- Half of these occur in individuals who had no history of a previous reac-
quently incriminated foods are peanuts, tree nuts, fish, and shellfish, but tion to an insect sting. 31
other foods, such as sesame seeds, have become increasingly important It has been estimated that the overall incidence of latex allergy in
as causes of food-induced anaphylaxis. 18,19 the United States ranges between 2.7 million and 16 million. Although
Medications are the second most common overall cause of anaphy- the incidence of latex allergy has risen markedly over the last 15 years,
laxis, and perhaps the primary cause of anaphylaxis in adults. They with the reduction of the use of powdered gloves and the substitution
20
are also the most common cause of anaphylaxis in the hospital setting. of nonlatex gloves in hospitals, the incidence of latex allergy appears
The most common classes of drugs producing anaphylaxis are antibiot- to have stabilized and perhaps declined. Populations at risk are those
32
ics, especially β-lactam antibiotics, and nonsteroidal anti-inflammatory experiencing multiple mucosal exposures to latex such as subjects who
drugs (NSAIDs). β-Lactam antibiotics account for as many as 22% of all have had multiple catheterizations, multiple surgeries, and of course
drug-related episodes. NSAIDs are the second most common medica- health care workers.
2
tion offender. Depending on the country, anaphylactic reactions dur- Exercise-induced anaphylaxis (EIA) is a rare disorder. One study
21
ing the perioperative procedure represent 9% to 19% of complications estimated the prevalence of EIA among Japanese adolescents to be
occurring during anesthesia. The fatality rate approximates 5% to 7%. approximately 0.03%, with no clear gender preference. Exercise-
33
Muscle relaxants account for 62%, latex approximately 16%, and the induced anaphylaxis exists in two forms. In one form the act of
remainder of reactions are due to hypnotics, antibiotics, plasma sub- exercise alone is sufficient to produce an event, and in another form
stitutes, and opioids. Other agents like antilymphocyte globulin and exercise plus a cofactor such as the ingestion of a food or drug is
22
antivenom antisera have been mentioned as causes of anaphylaxis. required. The prevalence of patients with purely exercise-triggered
Anaphylaxis to anticancer chemotherapy drugs is increasing in inci- anaphylaxis, relative to those who require exercise plus a cofactor,
dence with the increasing use of these drugs. In particular, reactions to is not known. Foods are the most frequently reported cofactor.
35
34
the platinum-containing drugs, such as cisplatinum and carboplatinum, NSAIDs and aspirin are the most frequently reported drug cofac-
are increasing in incidence. Anaphylactic events to biologic modifiers tor. 36,37 Other cofactors include alcoholic beverages, menstruation, and
23
are also growing in importance. These include omalizumab (anti-IgE), exposure to pollen during exercise. 36,38
an agent used to treat asthma, and cetuximab, a chimeric mouse/ The cause of anaphylactic events remains unidentified in as many as
24
human IgG1 monoclonal antibody to epidermal growth factor receptor two-thirds of adults presenting to an allergist/immunologist for evalua-
used in the treatment of colorectal cancer and squamous cell cancer of tion of anaphylaxis. A survey of 75 allergists in the United States found
the head and neck. 25 that these physicians had encountered 633 cases. The authors extrapo-
Radiographic contrast material (RCM) is used in more than 10 lated these data to the population of the USA and estimated there are as
million radiologic examinations annually in the United States. The many as 20,592 to 47,024 cases. 14
overall frequency of adverse reactions is 5% to 8%. Moderate reactions,
such as severe vomiting, diffuse urticaria, or angioedema, that require CAUSES OF ANAPHYLAXIS IN THE CRITICAL
therapy occur in about 1% of patients who receive RCM. However,
CARE UNIT OR OPERATING ROOM
The incidence of anaphylaxis during anesthesia has been reported to
TABLE 128-2 Mechanisms and Causes of Anaphylaxis range from 1 in 4000 to 1 in 25,000. Neuromuscular blocking agents
20
are responsible for 60% to 70% of anaphylactic reactions during general
Immunologic mechanisms (IgE dependent)
anesthesia. 39-41 In most series, succinylcholine is the most frequently
Foods: peanut, tree nut, shellfish, fish, milk, egg, sesame seed, and food additives cited agent but this may vary depending on the practice pattern, which
Medications: β-lactam antibiotics, NSAIDs, and biological agents determines the agent used. Most of the neuromuscular blocking agents
Venoms: stinging insects (Hymenoptera) cause direct mast cell degranulation and histamine release which are IgE
independent. However, life-threatening reactions to these agents usually
Natural rubber latex are IgE mediated. The tertiary or quaternary ammonium group, com-
42
Occupational allergens mon to all muscle relaxants, is likely the immunodominant determinant
43
Seminal fluid (prostate-specific antigen) recognized by IgE. The antigenicity of the shared ammonium struc-
Inhalants: horse, hamster, and other animal danders and grass pollen (rare) tures may be responsible for cross-reactivity among the muscle relax-
ants. Cross-reactivity occurs most consistently between pancuronium
Radiocontrast media and vecuronium. Cross-reactions also may occur between muscle
44
Immunologic mechanisms (IgE independent) relaxants and other classes of pharmaceuticals, based on in vitro inhibi-
tion of specific-IgE binding to the muscle relaxants. Agents that poten-
Dextran: high-molecular-weight iron dextran tially cross-react with muscle relaxants include acetylcholine, choline,
Infliximab morphine, neostigmine, and pentolinium. Cross-inhibition studies
45
Radiocontrast media suggest that previous exposure to these nonanesthetic drugs may sensi-
tize individuals to muscle-relaxing agents, resulting in reactions among
Nonimmunologic mechanisms
patients without prior anesthesia. Three out of four cases of anaphylaxis
Physical factors: exercise, cold, heat, and sunlight/UV radiation to muscle relaxants occur in females, suggesting cross-reactivity with
Ethanol ammonium compounds in personal care products. Skin testing may
46
Medications, such as opioids be useful to determine the safest alternative for subsequent anesthesia
following a suspected reaction, recognizing that nonimmunologic reac-
Idiopathic anaphylaxis tions are not identified by this diagnostic method. 47,48 Skin testing is not

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