Page 619 - Clinical Immunology_ Principles and Practice ( PDFDrive )

596 ParT fivE Allergic Diseases

but the prevalence varies: one study found 5–15 cases per 100 Other Rare Causes of Anaphylaxis
000 hospitalized patients for most analgesics and antibiotics, Anaphylaxis occurs during 1 in 20 000–47 000 transfusions of
whereas for dextran, penicillin, pentoxifylline, and streptoki- blood or blood products, especially in patients with IgA defi-
43
52
nase, the figure was over 30 cases per 100 000. Anaphylaxis ciency. IgA deficiency affects 1 in 500–700 Caucasians. One-third
has been reported after treatment with monoclonal antibod- of these patients have circulating anti-IgA antibodies, which are
ies (mAbs; basiliximab, rituximab, infliximab, omalizumab, associated with serious life-threatening anaphylactic reactions
52
44
etc.). IgE antibodies to galactose-α-1,3-galactose (α-gal) are to blood products containing IgA. Seminal fluid allergy is
thought to cause immediate anaphylaxis on first exposure to extremely rare, mostly affecting young women with atopy, with
cetuximab. 45 20% of cases developing life-threatening anaphylaxis. These
Drugs are known to be the leading cause of fatal anaphylaxis, reactions can be prevented with condom use or intravaginal
with the mortality rate in drug-induced anaphylaxis about one desensitization with seminal fluid. In cystic echinococcosis,
death per 50 000–100 000 treatment courses. 46 anaphylaxis can follow the rupture of a hydatid cyst during
All routes of administration can potentially be fatal, including surgery or as a result of trauma. 53
oral, intravenous, subcutaneous, intraarticular, intrauterine,
inhalational, rectal, or topical, but the risk is greatest after Anaphylaxis in Clonal Mast-Cell Disorders
parenteral administration. There is a link between unexplained anaphylaxis and clonal
mast-cell disease (systemic mastocytosis or monoclonal mast cell
Perioperative Anaphylaxis activation syndrome). In systemic mastocytosis, anaphylaxis may
54
Perioperative anaphylaxis occurs in up to 1 of 13 000 anesthesia occur to Hymenoptera stings and drugs (NSAIDs, opioids, and
28
administrations. The common causes of perioperative anaphy- drugs used in the perioperative setting). Patients with unexplained
laxis include neuromuscular-blocking agents, antibiotics, blood anaphylaxis should be evaluated for mast-cell clonality to exclude
28
and blood products, dyes, chlorhexidine, or natural rubber latex. systemic mastocytosis or mast-cell activation syndrome. 54
Reactions to neuromuscular-blocking agents mostly occur on
first exposure and have been associated with a 70% rate of Clinical Diversity of Anaphylaxis
cross-reactivity in this group; risk factors for fatal anaphylaxis In anaphylaxis, there is a remarkable range of clinical symptoms.
include male gender, history of cardiovascular disease, emergency Anaphylaxis can be preceded by prodromal symptoms, such as
47
setting, and use of beta-blockers. Latex remains an important tingling and redness of the palms and soles, anxiety, sense of
cause of intraoperative anaphylactic reactions. The antiseptic impending doom, and disorientation. Anaphylaxis most com-
chlorhexidine is increasingly recognized as a cause of IgE-mediated monly begins in skin and mucous membranes, is followed by
perioperative anaphylaxis. 48 involvement of the respiratory and GI tracts and the cardiovascular
system, and may finally proceed to cardiac and/or respiratory
Insect Sting–Induced Anaphylaxis arrest. Generalized urticaria and angioedema are the most
Following insect stings, life-threatening systemic reactions have common manifestations of anaphylaxis, observed in over 90%
49
been reported in 0.4–0.8% of children and up to 3% of adults. of cases, but may be absent. Respiratory symptoms may vary
Severe anaphylaxis from insect stings causes approximately 40 from rhinitis to laryngeal edema and airway obstruction, which
49
deaths annually in the United States and nearly 100 in Europe. are potentially life threatening. Cardiovascular manifestations
Occupational anaphylaxis caused by venom allergy can occur in anaphylaxis include hypotension and/or cardiac arrhythmias.
in bee keepers, gardeners, forestry or greenhouse workers, farmers, In adults, reduced blood pressure is regarded as systolic blood
50
truck drivers, and masons. The severity of reaction depends pressure of <90 mm Hg or >30% decrease from that person’s
27
on the type of insect, amount of venom, location of sting, the baseline values. Some patients present with only cardiovascular
patient’s sensitivity, older age, preexisting diseases, previous less collapse in the absence of other signs of anaphylaxis, especially
severe systemic reactions, concomitant treatment, mast-cell during general anesthesia. Anaphylaxis is usually associated with
51
disorder, and elevated baseline tryptase. Allergen-specific tachycardia caused by increased cardiac sympathetic drive in
immunotherapy with venom extracts has been shown to be safe response to a decreased effective vascular volume, but bradycardia
and effective in patients with Hymenoptera venom allergy, provid- may also occur. Anaphylaxis may result in up to 35% of intra-
ing some clinical protection within the first 8 weeks of treatment vascular fluid leaking into the extracellular space. A two-phase
and a long-lasting effect after 3–5 years of maintenance treatment reaction to the hypovolemia may present with tachycardia as
(Chapter 43). It is noteworthy that patients with systemic the first phase, followed by bradycardia when effective blood
mastocytosis are at risk of potentially fatal anaphylaxis to insect volume falls by 20–30%. 55
stings even if they are not presensitized to venom: this may be
attributed to venom components, such as phospholipase A2, CLiNiCaL PEarLS
acting as mast-cell liberators. 51 Diagnosis of Anaphylaxis
Latex-Induced Anaphylaxis • Anaphylaxis is characterized by extreme difficulty with breathing as
The prevalence of latex allergy has been estimated to be as a result of airway obstruction from angioedema/bronchoconstriction,
circulatory collapse, or both.
high as 1–6% in the general population, 8–17% in health • It is nearly always accompanied by tachycardia, usually by flushing,
31
care workers, and 67% in patients with spina bifida. urticaria, and panic, and sometimes by vomiting and diarrhea.
Latex-induced anaphylaxis has been reported in surgery and • Panic attacks do not involve airways obstruction, hypotension, or
dentistry and can be fatal. More than half the patients with urticaria but may be accompanied by faintness or tetany of the hands
latex allergy report allergic reactions to fruits, such as banana, as a result of hyperventilation.
avocado, kiwi fruit, chestnut, pear, pineapple, grape, and • Vasovagal attacks present with fainting, nausea, slow pulse, and pallor
without respiratory difficulty, diarrhea, or urticaria.
papaya.